As we begin to see multiple agents that will target BCMA with multiple mechanisms of action, the obvious question comes up about sequencing. How do you choose which one to use when? The reality is that, while many of the cell therapy enthusiasts may say, “CAR [chimeric antigen receptor] T cells are the answer. That is the only way we should go,” we know that certain patients cannot wait 6 to 8 weeks to get CAR T-cell therapy. We know, for instance, that not every patient wants to go in the hospital and experience the potential risk of cytokine release syndrome [CRS], or even be in the hospital at all. Each of these 3 mechanisms that target BCMA have their own relative advantages or disadvantages.

For instance, belantamab mafodotin is an easy off-the-shelf administered approach that does not require hospitalization, but it does require partnering with an eye care professional, and it can be associated with some keratopathy or ocular toxicity. There are pros and cons of each of those drugs.

CAR T cells require a manufacturing period and a strategy for bridging for many patients who may have refractory myeloma. They also require admissions to the hospital, chemotherapy for lymphodepletion therapy, and potential complications associated with CRS, including ICU [intensive care unit] stays or other potential prolonged hospitalizations as well.

The bispecifics or T-cell engagers, while they may not be as intense as the CAR T cells, they may often require hospital stays as well, and many patients, again, do not necessarily want to do that. There is a risk of CRS, but again, it is an immune-based therapy that appears to be potentially easier to give than a CAR T cell. It is a decision and a discussion that we are going to have with our patients about where they are in their specific journey as to which agent we choose at which different time.

I cannot tell you that I have an ideal patient for each of these drugs, but we make those decisions. It is unlike other drugs where, if you target 1 antigen, such as CD19 or CD20, you do not necessarily come back with a different drug. As I mentioned earlier, we do not lose BCMA expression with progression in most cases. If one drug does not work, you may be able to go to a second class or a third. You are not precluding exposure to one of these different mechanisms by using one of them earlier or later.

When we talk about the ultimate goal, it is to bring these treatments to earlier and earlier lines of therapy and eliminate the need for treatment for relapsed disease. Understanding how CAR T cells, bispecifics or T-cell engagers, and antibody-drug conjugates may be best used in the newly diagnosed setting will require us to revisit a total therapy-like approach. It may be that the ultimate treatment is an IMiD [immunomodulatory drug], a PI [proteasome inhibitor], and BCMA-directed therapy for a few cycles, then consolidation with an anti-CD38 antibody, then consolidation with high-dose melphalan, and a maintenance approach to get patients to MRD [minimal residual disease]-negativity. These may all involve different drugs, so by using these different noncross-reactive drugs, we may ultimately be able to get patients to MRD-negativity and cure them earlier in the disease course. How do we bring all of these approaches into earlier lines of therapy? This is the challenge for me and many others who deal in myeloma, and it is a challenge I look forward to because more treatment options are always better than fewer.

 As researchers, we would always recommend that a patient be considered for a clinical trial of some BCMA-targeting agent if it is available. If it is not, then how people end up making some of these decisions has to do with the state of the patient. Most of the available CAR T products need some time for the manufacture of the cell, so if a person has an aggressive relapse and is not particularly stable, then an off-the-shelf product is probably a better approach, and right now, that is belantamab, so that is what a lot of people would turn to. 

What we do not yet know is if there is an ideal order for these different BCMA-targeting therapies. Should you use one before another, or will that make a difference? Because of the way CAR T is being used in earlier lines of therapy, we are going to soon have an opportunity to find out if that BCMA-targeting approach does not last, or if we can use another BCMA-targeting agent if a patient relapses. There are data that BCMA can be downregulated on myeloma cells but that they come back. This has been researched a bit in patients who have received CAR T-targeting BCMA, and it has been shown that, over time, their myeloma cells will lose BCMA. But with further observation, that antigen comes back again, so that means that another BCMA-targeting drug would be useful, we would hope.

Everybody is interested in getting into that area of using BCMA for newly diagnosed patients. As I mentioned, there is a belantamab mafodotin trial that is looking at VRd [bortezomib, lenalidomide, dexamethasone] for patients with newly diagnosed myeloma. There is the KarMMa-2 study that is looking to incorporate CAR T for patients who have high-risk myeloma who we know are subject to relapse fairly quickly after an autologous transplant. The BMT CTN [Blood and Marrow Transplant Clinical Trials Network] is planning to use CAR T for either an early biochemical progression after an autologous transplant, or lack of having more than a VGPR [very good partial response].

We are hopefully going to have a high-risk trial as well, so that question is going to be answered. We are ultimately hoping to have a design where one of the bispecific engagers like teclistamab could be incorporated as an additional consolidation step following treatment either with or without an autologous stem-cell transplant. I suspect that, for all of those areas, we are going to see lots of research in the next couple of years.

With this whole area of specifically targeting antigens on myeloma cells, we have had 2 already available. We have had anti-CD38 drugs, and anti-SLAMF7, which are daratumumab, isatuximab for CD38, SLAMF7 for elotuzumab respectively. We now have belantamab mafodotin for BCMA. You are going to be seeing other targets emerging. There is GPRC5D, which is being developed as a CAR T target, and some others. We are going to see more and more of this kind of immunotherapy. It is not going to replace some of our good drugs like IMiD drugs or proteasome inhibitors, but more and more, this is going to be a step that patients receive treatment, either in the first line or early after a progression.

Videos

Influencing Factors to Initially Targeting BCMA in MM

As we have discussed, targeting BCMA through an antibody-drug conjugate is certainly an exciting treatment approach for which we now have an FDA approved drug to go after. To me, this is important and exciting because, as I mentioned, BCMA is in many ways an ideal target in the context of multiple myeloma. One of the challenges for us in the near future is how do we bring belantamab mafodotin into earlier lines of therapy so that we can partner it with other drugs? There are combination trials that are being evaluated. My colleague Ajay Nooka, MD, MPH, FACP, has reported on combining belantamab mafodotin with bortezomib and has demonstrated safety and efficacy. There are additional data combining belantamab mafodotin with pomalidomide. Figuring out the dose and schedule of an antibody drug conjugate in combination with other known active agents in myeloma is part of our typical strategy for bringing drugs that are approved in the refractory myeloma setting to earlier and earlier lines of therapy.

Now, the other targets for BCMA that are exciting are the CAR [chimeric antigen receptor] T cells, and we have several of them that are in development. These include idecabtagene vicleucel or bb2121. Orvacabtagene autoleucel is another one, or ciltacabtagene autoleucel, which is part of the CARTITUDE-1 study. There are a number of trials evaluating each of these 3, and there are up to 7 or 8 different BCMA-directed CAR T cells that are being done in phase 1 and phase 2 studies in myeloma. What is quite interesting is that we know, for instance, that the rates of grade 3/4 cytokine release syndrome [CRS] or neurotoxicity are significantly lower than what we have seen with CD19-directed CAR T cells in lymphoma or diffuse large B-cell lymphoma.

That is one difference between CD19 and BCMA. We also know, however, that there does not as yet appear to be a plateau on the treatment curve. This is unlike CD19 where, if you achieve a CR [complete response], and that CR is durable for 6 to 9 months, the likelihood of relapse drops significantly. In BCMA-directed therapy, it is not clear that that necessarily happens, so we need to learn more about the biology of CAR T cells in myeloma to understand how to maximize persistence and duration of response in many of these patients because the median progression-free survival looks to be somewhere around 11 to 12 months, at least for bb2121, which is the furthest along that we have.

Now, the third area that we are excited about when we target BCMA is the area of bispecific antibodies or T-cell engagers. These are antibodies that have been engineered to express CD3 and BCMA, and their function is to bring a T cell next to a myeloma cell by bringing BCMA-expressing, T-cell expressing, or CD3-expressing cells in close proximity. We know with CD19 and blinatumomab that this can be a highly effective strategy. We have seen in phase 1 studies, whether it is CC269, Amgen-402, or daclizumab, that these agents can be quite effective at the maximum tolerated dose. In many anecdotal situations, we are hearing that patients who progress on BCMA-directed CAR T cells may respond to the T-cell engagers, so this is an important next step in the biology and treatment approach for patients with myeloma. It certainly represents an important step forward for treatment of refractory myeloma.

At ASH [the American Society of Hematology 2020 annual meeting], there were updates on a lot of belantamab mafodotin data that continued to show high response rates. There were some interesting presentations about quality of life, where patients who responded to belantamab mafodotin reported increased quality of life with less bone pain and less fatigue. The ocular toxicity that people are aware of with belantamab mafodotin seemed to improve over time as patients got more drug exposure, which is great.

There is also another antibody-drug conjugate that Shaji Kumar, [MD,] presented: MEDI2228. This also had high response rates, but it has some interesting toxicities that have to do with the PBD [pyrrolobenzodiazepine] payload. They saw a fairly high incidence of photophobia in about 50% of patients. They also saw some trouble with pleural effusions, and rashes were pretty common in about a third of patients. Although they had very high response rates, they discontinued the agent after about a median of 3 cycles. I suspect that there is going to be more investigation about how to use that drug to capture its effectiveness and try to minimize toxicity.

There was a lot of CAR T action at both ASCO [the American Society for Clinical Oncology annual meeting 2020] and at ASH. There was a big presentation at ASCO by Nikhil Munshi, MD, looking at the update of the KarMMa trial where they had 128 patients. It had high response rates in the 75% range, 83% in those getting the highest doses, with manageable CRS. The most common toxicities ended up being hematologic, but the CRS that was serious was grade 1 or less. It was grade 1 in about 75% of patients, but beyond that, it very well tolerated and had low rates of neurotoxicity.

The CARTITUDE-1 trial was updated here at ASH by Deepu Madduri, MD. They had a large number of patients to present as opposed to a year ago. They also saw high response rates of about 97% with the CARTITUDE-1 trial. They are showing a bit of a different toxicity profile for a couple of reasons. One is that there was a slightly higher incidence of neurotoxicity that was significant compared to the bb2121 product. The onset of CRS is later, interestingly; instead of day 1, which is the median with bb2121, it ends up being more likely day 7. 

Some of the other updates on CAR T: the Poseida Therapeutics product looks good. The Chinese investigators here at ASH had a couple of presentations on different manufacturing methods and a dual-targeted CAR T targeting CD19 and BCMA, so that is a lot of action. It remains to be seen if one appears to be superior to the other. Of course, all these are being moved up earlier in the line of therapy to see whether there can be greater persistence of CAR T because that is one thing that has been a bit disappointing. As opposed to lymphoma, it does not yet look that there is a plateau in response in some of the heavily pretreated patients. Patients are still relapsing, so we obviously have to figure out how to make these products work better and work longer.

There was an update by Adam Cohen, MD, here at ASH on teclistamab, which has high response rates. That drug is already getting combined with other drugs. He presented data using this drug intravenously but also subcutaneously at a fixed dose. Their data looked very interesting.

The CRS was manageable: it occurred mostly with the first doses, and it then started to go down, so we are hoping that, perhaps after initial hospitalization when you receive this drug, you will be able to receive it as an outpatient. It has manageable CRS with just a low use of steroids. It has high response rates in the range of over 80% in heavily pretreated patients.

There is also the Celgene Corp product that was updated at ASCO, and it looks promising as well. Right now, that is still intravenous administration. They also had a presentation at ASH on Amgen [AMG]-701. AMG-701 is another bispecific engager that looks promising; it builds on their original data with AMG-401, which was a 4-week infusion. This is a weekly infusion, and it looks promising with high response rates and manageable toxicity.

Ongoing Approaches Toward Targeting BCMA

What we are probably going to be seeing more and more with belantamab mafodotin is that it is going to be combined with other agents and used earlier in the lines of therapy. There are some exciting phase 3 trials that are going to get underway shortly. One is being led by Robert Rifkin, MD, FACP, where he is using belantamab mafodotin in combination with Velcade [bortezomib] and dexamethasone and comparing that to daratumumab, Velcade [bortezomib], and dexamethasone. That is going to be a large international trial for people who have had previous treatment. There is a large study called DREAMM-9 where up front, patients are going to be randomized to receive Velcade [bortezomib], Revlimid [lenalidomide], and dexamethasone with or without belantamab mafodotin. Right now, that study is going to open to try to figure out what the ideal dosing is for the agent. It is probably likely that the Q3 [every 3] week schedule of belantamab mafodotin is going to change with some of these combinations where there might be some other toxicity issues. Lots of different drugs are going to be combined.

Right now, it is essentially for triple-refractory disease after 4 lines of therapy, but in at least some of the preliminary studies, like the study done by Ajay Nooka, MD, MPH, FACP, who presented some updated data on his combination of belantamab mafodotin with Velcade [bortezomib] and dexamethasone, it looks promising with high response rates. A combination like that would be carried forward a bit earlier. Particularly, it is going to be moving up because as daratumumab and other CD38 antibodies like isatuximab are going to be used in the frontline setting, there is going to be a consideration to use an anti-BCMA antibody much earlier in the lines of therapy, particularly if someone is on a CD38 agent when they progress since there are several maintenance trials going on looking at anti-CD38 antibodies post-transplant.

There are now going to be any number of agents that are targeting BCMA for obvious reasons; BCMA is a great target. One of the things that we do not know is about the sequencing of this agent, belantamab mafodotin, compared to a CAR T [chimeric antigen receptor T-cell] transplant that is BCMA directed, or a bispecific engager that is BCMA directed. There is a small study that was published looking at the use of belantamab mafodotin after some CAR T progressions. That looks interesting. We are going to be trying to figure out in the next year or two what sequencing is appropriate, or if you can go back and retreat patients with a different BCMA agent.

One of the most interesting trials that we [at the University of Wisconsin] have been able to be involved in is called DREAMM-5. This is a study that is combining belantamab mafodotin with some interesting agents that are essentially T-cell agonists to try to help with some immune response. We are interested in those drugs. One is combining ICOS [inducible T-cell costimulators], and there is also going to be a PD-L1 inhibitor. We are interested in looking at some of those combinations that are moving away a bit from the less traditional type of chemotherapy and more into the immunomodulatory type of drugs. We are interested in that.

Next Steps for Use of Belantamab in Clinical Practice

The poster that was presented at the American Society of Hematology annual meeting 2020 was focused on patient-reported outcomes with belantamab mafodotin. The interesting point to take home from this poster was that patients who had a good response to the drug—in other words, they had relapsed and refractory multiple myeloma, and they were placed on belantamab and had a drug response—had a very high degree of satisfaction with the drug despite that many of them had some types of adverse effects, including ocular and visual adverse effects. This is important for both oncologists as well as ophthalmologists to understand: every patient will have a different level of tolerance for drug adverse effects.

For example, for a patient who is otherwise doing well and is healthy, if you all of a sudden tell them, “Your vision is going to be blurry at least temporarily while you are on a certain treatment,” that would probably be difficult to accept for the patient. For the particular patient population in whom belantamab is being used at present, they have tried multiple different antimyeloma drugs, and those drugs have not worked. If they are having a response to the drug, they then have a greater degree of tolerance for those types of [adverse] effects. Of course, as an ophthalmologist, I have an interest in mitigating and relieving those [adverse] effects as much as possible, but even for myself, I have to put that into the context of the patient’s overall well-being and what their goals are with therapy.

The impact on prolonged dose delays of belantamab is an area that is being investigated by the drug manufacturer. As far as the data in the DREAMM-2 study, there did not appear to be, to my knowledge, any adverse effects of the dose delays and dose reductions that occurred as a result of ocular toxicity.

With that being said, as patients are treated for longer periods, if and when they develop degrees of ocular toxicity that may require multiple dose holds, that information will be informative in telling us what the long-term effects of these ocular-related dose holds on the efficacy of the drug are, more so for my oncology colleagues. That is an active area of investigation as doses and treatment schedules are being looked into.

My advice for community oncologists in terms of managing toxicities that are occurring, specifically the ocular toxicity, is No. 1, to try to become familiar with the ocular toxicity. A good resource is the manuscript that we [at the University of Chicago Medical Center] wrote that was published in the journal 

, that showed the ocular findings from the DREAMM-2 study.

In addition, if you are going to place patients on this drug, it is imperative to find an ophthalmology or optometry partner who is willing to take this on, because they are going to be vital in providing that pre-treatment evaluation throughout the course of therapy for these patients. That is key to making sure that the process is smooth, and that the patient and you both have a positive experience. It has to be a team approach.

Oftentimes, the patients themselves are important lines of communication. For myself, for example, it is relatively easy because I am in an academic center. The oncology team and I are on the same electronic medical record. I can simply send my notes or a message to the oncology team, but that may not be the case in the community setting. That direct line of communication with the eye care provider is important, but so is making sure that the patient knows what to communicate to the oncologist as well as the eye care provider about what they are experiencing with their vision and what their expectations and hopes are for this drug and their quality of life while they are on therapy.

DREAMM-2 Trial Regimen: Safety Updates and Dose Delay

As with any monoclonal antibody, we know that there can be other adverse events in addition to the keratopathy I just mentioned. If we look at data in terms of other adverse events, the second most common after keratopathy was hematologic toxicity, which is not a surprise. Thrombocytopenia was noted as well as neutropenia, and in some cases, anemia. We know that, unlike other monoclonal antibodies that have been administered in myeloma, the rate of infusion-related reactions is quite low. They tend to occur with the first dose, but it can be reduced significantly with the use of steroids and antihistamines. It is a relatively low event, especially considering what we see with daratumumab or with elotuzumab for first event infusion-related reactions.

In terms of the long-term follow-up of ocular events, as a result of the fact that this drug, belantamab mafodotin, has not been available, you do not have data for it for multiple years. We do not know what the potential long-term adverse effects are going to be. However, for those patients who were followed beyond the limitations of the trial, we saw that these lesions tended to resolve and that their visual acuity returned back to baseline.

The key point is that a significant percentage of patients develop these lesions, but once there is either a dose hold followed by dose reduction or if the treatment is stopped due to completion of therapy or another reason, those patients went back to baseline.

The optimal management and monitoring strategy of ocular events requires a degree of coordination between the ophthalmologist or optometrist and the hematology-oncology specialist. This is, in part, due to the fact that patients need to have an eye exam at baseline and then prior to every infusion, which is generally scheduled once every 3 weeks.

This requires some cooperation on the part of the ophthalmologist to agree to take on these patients. I would argue as an ophthalmologist and for my ophthalmology colleagues that this is an opportunity to have an impact on patients that is somewhat unique compared to what we normally do in our clinical practice because we hope to facilitate a reasonable quality of vision and quality of life for patients with multiple myeloma who are on belantamab, which they may be getting after having failed 3, 4, or 5 other agents. Our examination and our reporting back to the oncologist is critical for the patient to either get their next dose of the medication or for us to recommend a dose hold because of the impact that it is having on their cornea and on their vision.

That coordination and communication is important because once the patient is scheduled and an ophthalmologist agrees to take on this patient, each time that patient has an appointment, the ophthalmologist will follow the grading and dose modification guidelines that are provided in the prescriber information for belantamab and then report back to the oncologist about what they see. As an example, in my practice at the University of Chicago Medical Center, there is pretty frequent and regular communication between myself and the oncology team, which includes the nurses as well as the attending physician, in terms of what the patient is experiencing both subjectively and objectively as well as the grading of corneal lesions and what my ultimate assessment is about whether a dose hold would be recommended based on the criteria.

With that being said, as an ophthalmologist, I also understand that my job is basically to perform the grading and assessment of the corneal changes and relay that information both to the patient as well as the oncologist. The decision to treat or to do a dose hold is up to them, so that communication link has to be strong to make this all work in the best interest of the patient.

The specific management of keratopathy at the present time, with the knowledge that we have, is most heavily reliant on dose holds and dose modification. The reason for this is that we have seen in the DREAMM-2 study as well as from seeing patients post-FDA approval that when the drug is held, the corneal changes seem to resolve. In some patients, they resolve faster than in others, but we think that this is a dose-dependent phenomenon.

This is why, in the package insert in the prescriber information, the guidance in terms of management is this: once there is grade 2 or higher keratopathy, meaning microcyst-like epithelial changes, the presence of those lesions or decrease in visual acuity associated with those lesions will warrant a hold of the dose. Once the dose is held and the cornea and vision go back to baseline, then the medication will be resumed at a lower dose.

Another aspect of treatment for these patients that has been recommended is eye lubrication, preferably with preservative-free artificial tears. The reason for that is that we have seen patients with dry eye, and the DREAMM-2 study data showed that patients with a history of dry eye had a greater chance of developing grade 2 or higher microcyst-like changes within the epithelium. Because of this relationship, we as ophthalmologists have encouraged patients to be on lubricated eyedrops, preferably preservative-free artificial tears, as frequently as 4 to 6 times a day.

If I look to the future, I hope and suspect that there will be more directed therapies that will become available for the type of corneal changes that we are seeing as the exact pathophysiology of the changes are confirmed and once directed therapies are developed.

Management of Ocular Events From DREAMM-2 Regimen

One of the unique adverse events associated with belantamab mafodotin is an ocular toxicity: keratopathy. Functionally, what that means is that patients develop microcysts in the cornea, and those microcysts cannot be seen by you or me unless we have a slit lamp examination. To give belantamab mafodotin, it is important that you partner with an eye care professional so that they can do slit lamp exams before each dose of belantamab mafodotin is administered. One may say, “This sounds complicated. Do you have to have a specific ophthalmologist to work with?” One of the important take-home messages is this: if you can find an ophthalmologist to work with, that is great, but even an optometrist can see and grade the keratopathy as evidenced by microcysts using a routine slit lamp exam.

If you look at all the patients who were treated at the 2.5 mg/kg dose, roughly 70% of patients had some form of keratopathy as demonstrated by an exam from an ophthalmologist. It is important to recognize that every exam finding does not correlate to clinical findings, so finding that intersection between exam and clinical findings is what you do in partnership with your eye care professional before you give a dose of belantamab mafodotin. As an example, if we look at the DREAMM-2 study, in the 2.5 mg/kg group, as I mentioned, 70% of patients may have keratopathy as measured by an exam finding, but only 50% have any true symptoms at all. The most common symptoms that we see are dry or itchy eyes, which can sometimes be alleviated through lubricating eye drops, which are recommended at the time you start belantamab mafodotin therapy. 

If you drill further down in the data, only 18% of patients had changes in visual acuity, which means a reduction greater than 20/50 in their best eye. While you may see 50% of patients who had some symptoms like dry or itchy eyes, only 1 out of 5 patients will have any true changes in visual acuity. In the DREAMM-2 study, only 3%, or 3 patients, had to discontinue belantamab mafodotin because of ocular issues. The keys to managing ocular issues are dose holding or dose modification. This is unlike other medications where, when you hold the dose, you have this fear that you are going to lose control, particularly in the context of refractory myeloma. Because the half-life of belantamab mafodotin can be so long in some patients, only 10% to 15% of patients lost control of their disease during dose holding or dose modification. It is OK to hold the dose until the keratopathy or symptoms improve such that you can reinitiate therapy. In some patients, the dose was held 6 weeks or longer, so that is OK. Allow the keratopathy to resolve with dose holding and dose modifications.

We know from longer-term follow-up that almost no patients had irreversible ocular changes: they almost all recovered. The ones for whom we cannot say that with clarity are because they progressed or came off study and had other treatments that were administered to them at that point. It is not like there are patients who have irreversible ocular toxicity. From what we know about the data, that is not a significant concern with appropriate dose holding, dose modification, and partnerships with eye care professionals.

The DREAMM-2 trial for belantamab mafodotin showed us the ocular adverse effects. In terms of ocular safety, it was important to develop an understanding of what the rate of ocular toxicity that occurs with this drug is, as well as what the impact on visual acuity and visual function is. What are the short-term and long-term implications for patients?

In general, the DREAMM-2 study showed from an ocular safety standpoint that a significant proportion of patients develop ocular adverse effects. Most predominantly, this includes the finding of microcyst-like changes within the corneal epithelium, which in our University of Chicago Medical Center recent paper, we have called microcyst-like epithelial changes, or MECs. Roughly 70% of patients in the DREAMM-2 study developed these MECs.

We also know, based on looking at both the location data, meaning location within the cornea that these lesions were present, as well as the impact on visual acuity, that in a significant number of patients who develop these microcyst-like changes, there is no impact on visual acuity. That is reassuring. In other words, for a number of patients who will develop these lesions within the cornea, they will continue to have their baseline vision or vision to pursue their activities of daily living. However, a significant portion of patients, closer to about 50%, had some decrease in vision associated with these lesions.

We have some parameters by which that decrease in visual acuity was defined. For anyone with a decrease of greater than 1 line of visual acuity, we would pick them up using our visual acuity metrics in the DREAMM-2 study. With that being said, the patients who developed both MECs and a decrease in visual acuity, at the time of data cutoff for all those patients for whom there was adequate follow-up, these lesions and their visual acuity returned. The lesions resolve and visual acuity returned back to baseline.

From a safety standpoint, what we are seeing with belantamab and what we saw in the DREAMM-2 study was that a significant majority of patients developed cornea lesions, which we call microcyst-like epithelial changes. A significant portion, although not all of them, roughly 50%, also had some level of decrease in visual acuity, but the patients for whom we had follow-up at the time of data cutoff, they resolved. We also saw that, with a number of patients—and I have seen on my own anecdotal experience—with dose holds and dose reductions, these lesions also tend to recover. That was valuable information that was provided as a result of the DREAMM-2 study.

DREAMM-2 Trial Regimen Safety Profile

One of the exciting areas of new development in myeloma was the recent approval of belantamab mafodotin. Belantamab mafodotin was approved in a randomized phase 2 trial called the DREAMM-2 study, and in the DREAMM-2 study, we at the Winship Cancer Institute randomized patients between 3.4 mg/kg of belantamab mafodotin, which was the MTD [maximum tolerated dose] from the phase 1 trial, and 2.5 mg/kg of belantamab mafodotin, which was a dose recommended by the FDA to see whether the adverse event profile was different.

In that trial, we looked at the primary end point, which was overall response rate, which was about 30% to 32%, and it was similar between the 2 different doses of belantamab mafodotin. We then looked at the progression-free survival [PFS], and it was about 3 months, which is not dissimilar from what we saw with pomalidomide/dexamethasone in the same patient population, for daratumumab in the same population, and for carfilzomib in the same population of patients with refractory myeloma. We then began to look at DOR [duration of response], and we noted that the DOR for patients who achieved MR [minimal response] or better, was somewhere around 11 months, which now puts it at one of the longest durations of response of any approved drug in the refractory myeloma setting. This is important because DOR, in my mind, speaks to a balance between efficacy, as measured by overall response rate, and safety.

For drugs that do not have a great safety profile but can induce a response, the DOR and the PFS are similar, but in drugs that can be managed, and responders can be kept on therapy, you see that the DOR is substantially longer than the median progression-free survival. We saw this for daratumumab, for which the DOR was somewhere between 9 and 10 months, and in belantamab mafodotin, we see this as well: the PFS was 3 months, but the DOR was closer to 11 months. We know that, in these responders, the median overall survival is likely in excess of 13 months, which is significantly longer than the 6 to 11 months that I mentioned earlier as the median expected survival for patients with triple-class refractory myeloma.

Now, we also did some subanalyses from the DREAMM-2 study evaluating patients with high-risk genetics vs everybody without high-risk genetics. We demonstrated that the PFS and overall response rate were similar between those 2 groups of patients. We also looked at patients who had a renal insufficiency or were older, and we saw similar results: they were balanced between the 2, and there was no detriment in PFS or overall response rate between those groups.

We then looked at patients who had earlier treatment, meaning relapsing on 5 or fewer lines of therapy vs 6 or more prior lines of therapy. The overall response rate and DOR appeared to hold up in that patient population as well. This suggests to me that belantamab mafodotin is an important new treatment approach for patients with triple-class refractory myeloma. It being dosed once every 3 weeks is a reasonable approach in partnership with an eye care professional to treat patients with refractory myeloma.

DREAMM-2 Trial Efficacy Data and Recent FDA Approval

 One of the exciting, important developments in the context of myeloma is the realization that 

, or B-cell maturation antigen, is an important target in multiple myeloma. We are excited about this target as opposed to others, such as 

 CD38, because BCMA is much more narrowly expressed on plasma cells. There may be some mature phenotypes of B cells that express 

, but their expression numbers are much lower, and it is almost exclusively expressed on mature plasma cells. The target we’re going after is more selective than other targets we have in multiple myeloma.

 is also important for a number of points. A number of things occur to a myeloma cell that has been transformed, including proliferation, drug resistance, and overall survival of myeloma cells, all of which are governed by a 

 through ligation with its ligands, BAFF and APRIL, which are often circulating in the blood. When 

 is blocked with a receptor, whether it’s an antibody-drug conjugate, a T-cell engager, or a CAR [chimeric antigen receptor] T cell, you take out 1 of the major resistance factors for malignant plasma cells and potentially may resensitize them to other agents. Additionally, there’s very little expression at all on stem cells and nonhematopoietic cells. The 

 is in many ways an ideal target in multiple myeloma because of its more selective expression on plasma cells and the role 

The Rationale for Targeting BCMA in Multiple Myeloma

 Of the challenges we have struggled with in caring for patients who have seen multiple lines of therapy, of particular note are patients who are triple-class refractory or resistant to the proteasome inhibitors, immunomodulatory agents, and CD38 antibodies. Our treatment options are fairly limited at that point. Often, we will recycle previous agents in different combinations and hope we can get responses. Alkylator-based therapy, such as cyclophosphamide or melphalan, may be agents that we bring into play in this context. Combination chemotherapy approaches such as VDT-PACE [bortezomib, dexamethasone, thalidomide, cisplatin, doxorubicin, cyclophosphamide, etoposide] or DCEP [dexamethasone, cyclophosphamide, etoposide, cisplatin], may be treatments that we use as well, but unfortunately all those recycling or chemotherapy-based approaches have a limited life span. In all likelihood, you usually get 30 to 60 days of those treatment approaches. It has been new drug approvals and access to clinical trials that have really made a difference for patients with refractory myeloma.

What we know about patients who have reached the triple-class refractory stage of myeloma is that their median expected prognosis or survival is somewhere between 6 and 11 months. This has been demonstrated in a couple of retrospective analyses looking at daratumumab-resistant patients, such as in the MAMMOTH study as well as in the work of Dr Ajay Nooka from our group at Winship Cancer Institute, who demonstrated that the median overall survival for patients in this category is quite short. That is where we begin to look at the efficacy of new drugs. Can they really push the boundary of median overall survival in addition to response?

When we begin to think about what the treatment options are for patients who have had 4 or more prior lines of therapy, functionally, their condition is triple-class refractory. They are resistant to proteasome inhibitors, they are resistant to IMiDs [immunomodulatory drugs], and they are resistant to anti-CD38 antibodies. There are potential options in addition to recycling previously used agents or chemotherapy-based approaches. One approach that was recently approved is belantamab mafodotin, or belamaf, and this is 1 recent approach using an antibody-drug conjugate targeting BCMAs [B-cell maturation antigens] that provides significant potential benefit for patients. 

The other agent in this situation is the use of selinexor, which is a first-in-class XPO1 inhibitor. Selinexor was combined with dexamethasone in the STORM trial and was FDA approved for a similar pretreated patient population. There are some challenges to both of these medications, but with appropriate supportive care this can be used. It is important to recognize that the ongoing, unmet medical needs include management of patients who are frail, patients who have renal insufficiency, and patients who developed oligo-secretory myeloma, because unfortunately many of these patients are not eligible for clinical trials. Their treatment options in the refractory myeloma setting can be quite limited.

One of the things that we do when we try to assess what treatment approach might be suitable for a patient with refractory myeloma is to understand what their current symptom burden is and how much of that symptom burden is related to myeloma vs comorbid conditions that may or may not get better. What other specific issues such as travel, co-pays, and distance from the clinic impact patients’ treatment? All those things play into those decision-making processes. It is important to recognize that not all patients with 4 or more prior lines of therapy are going to be able to take aggressive therapy. Trying to understand how you tailor the treatment approach to what they need is 1 of the clinical challenges we struggle with in this situation.

Treatment Approach for R/R Multiple Myeloma

Let’s close with the question of pros and cons of CAR T, antibody-drug conjugates, and BiTEs [bispecific T-cell engagers]. Let’s assume that these are probably going to move earlier in treatment into an early relapsed settings. Why would you choose 1 over the other?

Well, everybody here probably has the same thoughts, that as these agents get moved up earlier, we’re all very interested to see some of the earlier data, like KarMMa-3, when you are offering CAR [chimeric antigen receptor] T-[cell therapy] after only a couple of therapies. If you start seeing patients and then have durable responses for years, that’s going to be fairly persuasive. The question is whether we’ll be able to do 1 sequential BCMA therapy after another and then what sequence should you do this in.

We’re going to ignore cost right now because, of course, this is not cheap. Noopur, what do you think? Where are we going to use these?

 I think they’re all going to move earlier and earlier. Some of the things we’ve talked about—in terms of disadvantages of taking 4 to 6 weeks to produce, etc, are going to go away. We are going to be able to do it earlier, without having to worry about things like a bridging therapy. We have to think about sequencing some of these BCMA targets, because 1 of the good things about CAR T cells is it’s 1 and done. If we are able to see a durability of response, in my mind, that’s going to be a huge benefit for our patients. On the other hand, as we bring them earlier, if we don’t see a remission duration that is long lasting, and we’ve got to pull back with some of these other agents, then it’s an open area, and we will be talking about sequencing some of these BCMA-targeted approaches.

Tom, if you had a patient today who had 3 or 4 prior therapies, and if all 3 were available, would you have a preference for antibody-drug conjugate over a BiTE? We’ll take CAR T out of the equation for now.

 The bispecific antibodies are going to be extremely potent for all these patients. It’s going to be moved to front line in early relapse quite quickly. These response rates are 80%, 90%. It’s amazing, actually. I would prefer that bispecific.

 I agree with Tom in general. For a triple-class refractory patient, if I had the choice between an AC [antibody-drug conjugate] and a bispecific BCMA target, I would lean toward the bispecific. If I had a patient with significant cardiopulmonary disease who I was concerned may not tolerate cytokine release syndrome, I might gravitate toward the antibody-drug conjugate in that scenario. Otherwise, most patients would get the bispecific antibodies. I have a similar level of enthusiasm as Tom does. If the response rates, the durability of those responses are similar to what we’re seeing with CAR T cells, that’s a game changer. Although Noopur is right: Patients enjoy that treatment-free interval. That’s 1 of the most valuable things for them after going through CAR T-cell therapy.

There you have it, folks. Everybody is very excited about BCMA-targeted therapy. We have numerous, probably over a dozen agents in the clinic right now being studied who will probably transform how we treat myeloma. Lots to learn and lots of work to be done to figure out where we’re going to use them most effectively and most cost effectively as well.

I thank the panelists for their time today. It’s been a great discussion. We’ve covered a lot of ground quite quickly. With that, I’d like to thank you all for this, Dr Callander, Dr Martin, Dr Raje, and Dr Voorhees. And thank you to our viewing audience. We hope you found this 

® discussion to be useful and informative.

Future of BCMA-Targeted Therapies in Multiple Myeloma

I want to review the data for bispecific antibodies, or BiTEs—slightly different technologies, but we’ll lump them together for today. Peter, you’ve had some experience with some of these. Do you want to talk us through that?

 Sure. At LCI [Levine Cancer Institute in Charlotte, North Carolina], we’ve been involved in the phase 1 Janssen study of teclistamab. This is a BCMA-targeted bispecific antibody. This is a 2-pronged antibody, as I describe it. One prong of the antibody binds to BCMA on the surface of plasma cells. The other prong of the antibody binds CD3 on T cells and activates T cells, basically creates an immune synapse between the T cell and the myeloma cell, and engages that T cell to destroy the myeloma cell—the blinatumomab, if you will, of multiple myeloma.

There are several different products out there. There’s AMG 420, which was the first proof of concept of BiTEs in this specific space. The problem with AMG 420 was that it had to be administered as a 4-week continuous infusion, much like blinatumomab must be administered. These next-generation BCMA bispecifics have a longer half-life and can be dosed less frequently. In the teclistamab phase 1, the bispecific antibody was administered with step-up dosing during the first week and then weekly therapeutic dosing thereafter. My colleague presented this data at ASCO [American Society of Clinical Oncology Annual Meeting]. At the higher-dose level that they looked at with the IV [intravenous] formulation, they’re seeing response rates at this point of 67%—granted, with a very small number of patients, 12. But the patients I’ve treated on these things have very refractory disease and extramedullary involvement, and I’m seeing really quite impressive responses and durable responses with this agent.

 That seems to be a common theme to all the BiTEs. We have many of them in clinical trials, at least 6. Not to pick on anyone specific, but Tom, at ASH [American Society of Hematology Annual Meeting] you presented on a different one from a different company. Tell us about the results of that, and the toxicity.

 We have been part of the Celgene trial for their bispecific T-cell engager. And it was presented by Dr [Luciano] Costa at ASH. They did a first-in-human dose-escalation trial, then they treated 9 patients at what they believe is going to be the dose. They took to an expansion and then to a phase 2, which is a step-up dose of 6 to 10 mg, and then some patients at 10 mg. There were 9 patients treated at that higher dose, who had 8 of 9 responders. And 5 of those people are MRD [minimal residual disease] negative. It’s pretty impressive, actually—a response rate of almost 90% for these 9 patients.

I have a few patients on it. When patients get on it, it appears durable. The big question, in the waterfall plot that was shown at ASCO for teclistamab, there were patients out 19 months. Most of the patients who were out 12 months were still continuing in response. The question is, will it be as good as the CARs or not? We’re all really looking forward to seeing those data. This might be easier.

The problem is, it does require a hospital stay. The toxicity is the cytokine release syndrome, or CRS. It requires a hospital stay for the first dose and every step-up dose, because you might activate more T cells each time. But after you’re done with the step-up dosing and the first real dose and then the T cells, there is essentially no CRS. Patients may need to be hospitalized once, twice, or 3 times before they can continue, but then can continue in the outpatient clinic thereafter.

The neurotoxicity is also similar, but much less—less than 10% neurotoxicity. You still do see some cytopenias. About a third of the patients do get cytopenias. But as you said earlier, this is a really heavily pretreated population. Maybe it’ll be less if we do it in less heavily pretreated patients. Of all the agents, these are my favorite.

 We’ve used a couple of these agents targeting different companies, different agents. My impression is they’re a lot less toxic than CAR [chimeric antigen receptor] T cells, and I suspect they could probably be delivered safely as an outpatient from the majority of patients, particularly if you had some home monitoring system you could use. Also, to go back to CAR T, for some of those products on the horizon, they may not require hospitalization for everybody, at least initially. The other thing I’ve been a bit concerned about is unlike CAR T, at least in my experience, the remission duration has not been as long. The people do progress more quickly, at least in my short experience. This is something you have to pay attention to. But off the shelf, you don’t have to wait. There are good high response rates, and obviously this is going to be a very important addition to our therapy.

Bispecific Antibodies for Multiple Myeloma

 Peter, do you see any difference between them that strikes you that is worth calling out at this point? Or are they all still too early to see?

It’s too early to know. The overall response rates in all of them are obviously quite high. Depth of response is quite good. Median duration of follow-up remains quite short, and it’s important to recognize that this depth of response in a lot of these patients continues to deepen over time. I have [treated] patients for 1 to 2 years who are finally getting into complete remission. We have to wait in order to see any meaningful differences between the products.

 I agree with what Noopur [Raje] and Pete have said. One issue that has come up in our experience is that the manufacturing time can be daunting for patients. That doesn’t sound like a long time, 3 or 4 weeks. But there is this issue of patients falling apart during that interim and you are unable to get them to transplant. A lot of the trials are restrictive in what you can give patients, unfortunately. I’m not sure it makes a big difference what you’re trying to do in terms of this bridging. We should try anything. But that’s still a hurdle. Going back to other BCMA [B-cell maturation antigen]–targeted therapies, that is a disadvantage, that you just cannot immediately give it to an ill patient.

 We’ve been lucky at UCSF [Helen Diller Family Comprehensive Cancer Center] because we’ve had all the products in clinical trial. I agree with everybody that there’s no real difference at the current time. We’ve been very excited over the overall response rate. But a couple of limitations: 1, patients must come to the licensed cellular therapies place, like the transplant center. And that’s going to be a problem for a lot of patients. This isn’t going to be for everybody, unfortunately. It’s probably going to be less than half the people who are going to be referred for CAR [chimeric antigen receptor] T-cell therapy because they have to come into the transplant center.

Then we’re all excited about the response rate. But the disappointment is, for most people, the relapsing. Relapses continue to occur 1 year down the road, 2 years down the road, 3 years down the road. That’s a stark contrast to lymphoma, where if they’re in remission for 6 months, they tend to be in remission forever, which is troublesome. I wonder what the advisers think. For me, the problem is, are these guys all going to need maintenance after the CAR? We just haven’t addressed that situation at the current time. They’re going to need something else other than just a CAR.

In fairness to the products, these are the worst of the worst patients in terms of the number of prior therapies and what their natural history would be. To me it’s quite miraculous that some of these patients pick up their bed and walk and have their first complete remission that lasts, even if it lasts for only a year, it’s often better than what the alternative was going to be.

 One of the most exciting things that we’re all going to be dealing with is, what about re-treating people with a different BCMA-targeted therapy. We use a drug conjugate after a CAR T, or can you use a BiTE [bispecific T-cell engager] before a CAR T? A lot of the trials are set up, so answering those questions now is quite limited. But we’re all going to try that. There are persuasive data that BCMA could be downregulated at the time of a CAR T relapse but comes back very quickly, particularly in people who have quite proliferative myeloma.

Differentiating among CAR T Products for Multiple Myeloma

Let’s discuss our favorite topic of CAR T-cells, Noopur has the most experience of all of us in using CAR T. Do you want to just give us a lay of the land, Noopur? Where are we at with these, and what’s your impression as we’ve get more experience?

: We were waiting on cellular therapy for myeloma and we now finally have them. We have several different products. All of them in the myeloma space are targeting the same protein, BCMA. And there are different products out there, including one from Janssen, one from Juno, one from bluebird, and one from Celgene. And the big differences are the way they are creating the CAR. All of them are using a very similar post-stimulatory domain, which is 41BB. And this is required for T-cell expansion. CAR T-cells, unlike what people really talked about with bela and maybe the BiTEs, which we will talk about later, this is not off-the-shelf. This requires collecting cells from patients, getting those cells back to whoever is producing the CAR, and from collecting the cells to creating the CAR T-cells, it can take anywhere between 3 and 4 weeks right now. And then once those CARs have been generated, we get the patients back. And they do need to be hospitalized, at least for right now.

This might change in the future. We’ll have to wait and see. But most patients will receive some conditioning chemotherapy, and we typically use a combination of Cytoxan with fludarabine, and following 3 days of that, 2 days of rest, and then you give back these CAR T-cells to patients. The most important toxicities associated with cellular therapy are twofold. One is neurotoxicity, and the second one being cytokine-release syndrome. And these occur because of the CAR T-cells being active. Once the CAR T-cells finds your treatment cell, they destroy the tumor cell, produce a lot of cytokines, and that results in cytokine release syndrome. And the second one, neurotoxicity, which is less well understood, is again because of the CAR T-cells and whether or not it’s because of crossing the blood-brain barrier or whether or not it’s because of some of these acute-phase reactants, it’s still not completely clear.

The most important thing we’ve learned from CAR T-cell technology in the last couple of years is the fact that they work. We can generate them in very end-stage myeloma patients. They work with extremely high response rates, north of 80% in whichever clinical trial you look at. And it’s manageable toxicity. Most of the toxicity we’ve seen is cytokine release syndrome. And we’ve been able to manage that quite well. And we’ve seen very little in the way of neurotoxicity with these cellular products. It’s a really exciting space. We’re just at the beginning of cellular therapy in myeloma. And at least the initial look at this has been quite encouraging. The data looks quite exciting.

Development of CAR T Cells in Multiple Myeloma

Let’s start with belantamab. If you’ve had some experience with the drug, please describe in detail what the DREAMM-2 trial has taught us.

 We are fortunate to participate in the DREAMM-2 study. This was a large phase 2 trial looking at patients who were on at least 3 lines of therapy and had to be daratumumab refractory. Using this as a single agent, every-3-weeks IV [intravenous] administration, that’s very quick, with no steroids and patients liked that. The study was able to show that the response rate was about 33%. Two different dose levels were examined; 2½ mg is the dose we’re using. Many people have probably heard about the biggest toxicity. There’s some thrombocytopenia, which is quite manageable. But there is some keratopathy as well. Patients can develop dry, blurry, and irritated eyes. And that seems to be manageable in that, once the drug is stopped for a period of time, these resolve. In most cases, at least in our experience, the drug can be restarted. But we saw some very nice responses, including some sustained CRs [complete responses] using that drug. The research presented at ASCO [American Society of Clinical Oncology Annual Meeting] that Noopur talked about is combining this drug with Velcade, where that seemed to push the response rate up to almost 75%. But that’s a very small study and is just getting off the ground.

 We’ve been using it in the expanded-access program. We’ve put close to 10 patients on the expanded access. I have also been very impressed with the ease of administration, which is once every 3 weeks. We have a good ophthalmology group, so for us, it’s very easy for the patients to go to an ophthalmologist. They look at the surface of the eye. They tell us everything is OK. Patients can then get dosed with their next or subsequent dose. For us, it’s been convenient. We haven’t had a significant toxicity that wasn’t reversible.

What percentage of patients get this corneal toxicity, Tom, either from the study or your own experience?

 Upward of 70% of patients can have some corneal toxicity. And close to half the patients either have to hold the dose or have to dose reduce. It’s a significant number, and they have to be watched closely in terms of the ocular stuff.

 To be clear, 70% of patients had corneal findings on ophthalmologic examination. Not everybody had symptoms of those corneal findings, although dry eye, photophobia, and blurred vision were common adverse effects. Because of that, as Tom mentioned, there were a lot of dose holds and dose reductions. It’s going to be important to better understand why this is happening, to explore alternative dose schedules and other potential preventive strategies to mitigate this particular problem, because if it wasn’t for the corneal toxicity, this is a very easy agent to give.

 There was a substudy done looking at the use of steroid eye drops to prevent the keratopathy. Unfortunately, that did not seem to be helpful. But Pete’s right. The secret is probably going to be a change in the dosing schedule or maybe building in some positives, because the half-life of this drug is pretty long.

My experience with this class of drugs—antibody-drug conjugates, targeted BCMA [B-cell maturation antigen]—is that the high toxicity can be quite difficult for patients at times. In at least some of the patients I treated, it took quite a long time for the symptoms to resolve after they stopped the drug. What I found interesting, and I guess other people have seen, is that the response persisted.

Even though they were off the drug for quite a long time—and surprisingly so, in my experience, given the stage of disease the patients had—they would be coming 3 three months later. And I’d go, “Wow, you’re still in complete remission [CR]. That’s amazing.” Have others had that experience?

 Yes, absolutely. I had a patient who had a 6-month dose hold because of keratopathy and was absolutely stable. She wasn’t in a CR, but she had a deep PR [partial response] with an M-spike [monoclonal protein] that just sat there at 0.2 for 6 months.

 The median duration of response in the updated ASCO [American Society of Clinical Oncology Annual Meeting] presentation is 11 months, which is long compared with, for example, selinexor-dexamethasone from the STORM trial, where the median duration of response was about 4½ months. For those patients who respond, they respond very well in spite of those dose holds.

The other thing I noticed was the responses were quite deep. I had a couple of people go into complete remission, which was kind of surprising. It’s definitely a drug to watch. I think you’re right. This issue that the responses can be quite durable—and the half-life of the antibody, of course, is quite long—suggests maybe that, to me at least, the dosing schedule is something to look at rather than stopping and starting. Just have a longer time between treatments if they start to develop problems. Is that logical or illogical? What do people think?

 The combination we’re going to use it in, right? It’s probably not going to be most effective just as a single agent. We probably can use it in a lower dose like we’re talking about with selinexor, in combination with another agent. It’s a race to figure out which one is going to be the best combination.

 Noopur, where are you going to use this drug? At what stage of disease?

 Obviously, BCMA targets are all very exciting. The benefit of belantamab mafodotin is the fact that it is an off-the-shelf antibody. There is no processing. There is no waiting. And the toxicity, outside the ocular toxicity, is very manageable, completely outpatient. Given that we are already using daratumumab at the onset, at the final diagnosis, patients are all going to be daratumumab exposed at first and second relapse. All BCMA targets are going to come on earlier and earlier in their lines of treatment. Second and third line is where we’re going to use it. Just to put things into context, Natalie mentioned the response rate of belantamab mafodotin as a single agent. If you go back to the CD38 antibodies, single-agent CD38 antibodies had a similar response rate. It falls into that same category as a single-agent monoclonal antibody.

Yes, that’s absolutely true. Tom, where do you think you’re going to use it? We should be clear that right now, it’s got a specific FDA approval. Could you speak to that and then say where you think we’ll go in the future.

 I think it’ll get FDA approval in the triple-class refractory or the data exposed. I will point out, though, in the daratumumab-sensitive people, the single-agent activity was 60%. It wasn’t 30%. It was 60%. In the same patients daratumumab and isatuximab were used and got about a 25%, 30% response rate. This got a 60% response rate. This is a quite active agent. And of the BCMA agents, it’s the only 1 that’s not going to require hospitalization. All the other BCMA agents being tested nowadays will require some form of hospital stay. The off-the-shelf nature to it and the ability of the private practice doctor to give this drug—it’s going to be used a lot. This has a bright future, in my mind.

 Yes, you’re right, although I do worry about this corneal issue in terms of whether that will limit its uptake a little, particularly if you have other choices in early relapse. That may be something we have to continue to work on with the company.

Using Antibody-Drug Conjugates in Multiple Myeloma

 Let’s talk about the most exciting target we have in myeloma today, which is BCMA [B-cell maturation antigen] and how we can approach targeting that. Nooper, you’ve been quite involved in some of the drug therapies that are targeting BCMA. What is BCMA, and why do we care?

 BCMA is 1 of the most exciting targets that we’ve discovered in the last few years. 

 stands for B-cell maturation antigen. It is a protein that is expressed on all plasma cells. It’s present on all patients with multiple myeloma. Over the years, we’ve begun to appreciate that you don’t even need to measure BCMA levels, because all plasma cells will have that. This is a tumor-specific target, and going after this makes a lot of sense. We have a lot of different approaches to targeting BCMA. There’s conjugated monoclonal antibodies, which are in clinical trials. The 1 that is in development is belantamab mafodotin. This is a conjugated monoclonal antibody targeting BCMA, and there were nice data on the DREAMM trials presented at this year’s ASCO [American Society of Clinical Oncology Annual Meeting]. There are other strategies, such as BiTEs, which stands for bispecific T-cell engagers. These are also off-the-shelf monoclonal antibodies that target the same protein, and while doing so, they also activate your T cells and can bring the T cells to the tumor and can cause immune T-cell killing of the tumor itself. The most exciting space or the most data we have using BCMA as a target is the cellular therapy world, which is CAR [chimeric antigen receptor] T cells, again directed toward BCMA.

BCMA-Targeted Therapies in Multiple Myeloma

 Let’s discuss venetoclax, which has taken us by storm in the last year or 2. Tom, you were an early adopter of venetoclax. Tell us about your experience. What do you think of the BELLINI clinical trial? Maybe you could describe what that is.

 Venetoclax is an inhibitor of BCL2. We started using it in relapsed/refractory before selinexor was approved. We could get it in some patients by compassionate use. We had about a 20% response rate with venetoclax plus dexamethasone with people who were triple-class refractory. But what was found by several investigators is that those patients who have the 11;14 translocation likely have overexpression of the BCL2 pathway. But those people are exquisitely sensitive to this BCL2 inhibitor, and they had a really nice response. A phase 2 was done, randomized bortezomib–BCL2 inhibitor–venetoclax and dexamethasone vs bortezomib and dexamethasone, showing a benefit in people with 1 to 3 prior lines of therapy, all comers. That instigated the BELLINI trial, which was a phase 3 randomized trial, in patients with 1 to 3 prior lines of therapy. And patients are randomized to the triplet vs the doublet of bortezomib and dexamethasone. What we found is that the triplet actually was more toxic. In fact, there was higher mortality. It was updated at ASCO [American Society of Clinical Oncology Annual Meeting] this year by Dr Shaji Kumar showing that that toxicity still persists, that there were more GI [gastrointestinal] toxicities, more infections, and there was some cardiac toxicity in the triplet vs the doublet. In that study was a subset of patients who had the 11;14 translocations. Those patients had exquisite responses. The overall response rate was well over 90%. After 2 or 3 years, these patients remained in remission PFS [progression-free survival]. That curve is an impressive curve in the 11;14s. It’s going to be a great drug for the patients who have the translocation at 11;14. But for everybody else right now, they’re probably not going to move forward in that direction.

 Thank you, Tom. Natalie, are you using it in clinical practice yet?

 We would have, we have had a lot of trouble getting payers to approve it, even with the presence of 11;14. That’s been the biggest hurdle. We’ve had a couple of patients who were treated through the VA [Veterans Affairs Medical Center], where they’ve had nice responses again. This is going to be a drug for the 11;14. Unfortunately, because of the BELLINI trial results, it’s put a damper on a lot of the research that we’d all like to see done. Hopefully, there’s going to be recognition that there are patients who benefit from this. But it’s put the brakes on a lot of things.

 Peter, last word to you before we move on to something different?

: I agree that in 11;14-translocated, in 

-high patients, it’s a very active agent. We’ll see it eventually get approval there. I do want to give a quick shout-out to the daratumumab-venetoclax-dexamethasone data that presented at ASH [American Society of Hematology Congress] in December. The overall response rate was over 90%, and every single patient was either a VGPR [very good partial remission] or CR [complete response]. Granted, they were small numbers.

 Yes, I must say, I’ve used quite a lot of venetoclax, and these are very impressive results in the 11;14 population, as you’ve all said. Unlike Natalie, we seem to be able to get it quite easily, at least until a couple of months ago. I don’t know if that’s changed. For the folks watching, if you have an 11;14 translocated patient—first, test for it, because you won’t know unless you do the test. Second, a lot of the commercial labs aren’t running 11;14 testing. You have to be careful that they’re actually measuring it. And if you do find somebody with that, it’s a drug to consider as a single agent or in combination.

BELLINI Trial; Venetoclax-Vd in Multiple Myeloma

 New drugs are coming out. Let’s begin with selinexor, which has been approved by the FDA, so it is available. There are recent updates from the BOSTON study with the combination of selinexor with Velcade. Does anybody who participated in that want to comment?

 The STORM data were what got selinexor approved. The nice thing about the BOSTON trial is that they have used bortezomib on a weekly schedule, in a subcutaneous way. It’s more of a real-world way of using bortezomib. The other thing they’ve done with the selinexor in this combination is they’ve used weekly dosing of selinexor, although at 100 mg, so that’s something we can argue about. They did see a benefit in terms of a progression-free survival of a little over 4 months. This is hopefully going to get the drug finally approved. As far as selinexor is concerned, most of us still worry about the toxicity associated with selinexor. Depending on what your partner drug is going to be, it’s important to dose-modify selinexor so that it’s well tolerated, and patients can stay on medication.

 Let’s describe selinexor, for those of you who may not be familiar with it. It’s an orally delivered agent. It has a novel target, which is exportin, a protein that shuttles things from the nucleus to the cytoplasm and back. But it can be blocked by this drug, so it’s a completely novel mechanism of action. It is approved by the FDA as a single agent in heavily pretreated patients. They were called penta-refractory, 5 prior regimens with a response rate of about 26%. In this BOSTON trial that we’ve just described, was a randomized phase 3 trial of bortezomib-dexamethasone vs bortezomib-dexamethasone and selinexor. It was mostly done in Europe, because the control arm wasn’t that attractive in the United States. But as Noopur just pointed out, there was about a 4-month progression-free survival advantage.

 This was a logical way for them to get regulatory approvals in earlier relapse. Given the fact that we have other proteasome-inhibitor-based triplets that we’ve already talked about: daratumumab-carfilzomib-dexamethasone, soon to be isatuximab-carfilzomib-dexamethasone, pomalidomide-bortezomib-dexamethasone. In a similar patient population, just given the adverse-effect profile that Noopur alluded to, I don’t think we’re going to be using this a lot in this particular clinical scenario.

 Tom, what do you think? How are you going to be using it?

 We’ve reserved the use at the current time in the penta-refractory scenario where we don’t have anything left. We don’t have a clinical trial slot for a patient, and we don’t have any other therapeutic options. We have tried it, and it’s a tough drug to give. There’s no doubt about it. You have to be very diligent about checking their electrolytes, giving them fluids, giving them antinausea medicines, checking in with the patients. But you do get some patients who you wouldn’t believe you’d get a response to. It’s reasonable to try in patients, either in the combination of bortezomib-selinexor-dexamethasone, or just selinexor and dexamethasone. Give them a cycle and 4 weeks. Make sure they get through it OK. If they have a response, you can continue. But it is, in general, a lot more work than all the other regimens.

 In fairness to the drug, when it was dropped to weekly dosing, as Noopur described in the BOSTON trial, it apparently looked like it was quite a bit better tolerated, right?

 We’ve been participating in what’s called the STOMP trial, which has partnered selinexor with a lot of different agents. And we’ve been very impressed with 2 combinations in relapsed/refractory patients: carfilzomib with selinexor and dexamethasone. That has had a good response rate, as well as daratumumab and selinexor. We learned with other oral drugs, you get more drug in patients with lower doses. And we’ve been aggressive at cutting the doses. Then patients can stay on. As Tom said, in some of these very refractory patients, there have been some dynamite responses. We just don’t have a biomarker for it to say who’s going to be the person who responds, unfortunately. But there are some people I’ve treated who have really benefited.

BOSTON Study; SVd in Relapsed/Refractory Multiple Myeloma

 I’m surprised nobody mentioned daratumumab with bortezomib earlier. That hasn’t even been brought up as an option in a lenalidomide-refractory patient. Noopur, I’ll pick on you again. Why not use that?

 Well, part of the reason for not using that is that most of our patients have been exposed to bortezomib already up front. The issues around toxicity of bortezomib for long-term use is something we’ve talked about, the neuropathy specifically. If you look at the old data with bortezomib-daratumumab, although it was a positive trial, the data were not that impressive. In the CANDOR and the IKEMA studies, the data look much better. We tend to use carfilzomib at the time of relapse now. That might change with more people using KRd [carfilzomib, lenalidomide, dexamethasone] up front. But for right now, the go-to proteasome inhibitor seems to be carfilzomib at the time of first relapse.

 Many of you mentioned using pomalidomide. Tom, why not just use lenalidomide again? I gave the case where somebody was progressing on it, so I made it easy. But if you had lenalidomide and stopped it, would you use pomalidomide at relapse, or would you go back and use lenalidomide again?

 If there’s been a significant 6- to 12-month break, and they’re truly not refractory to lenalidomide, it’s acceptable to give that a try, as long as they didn’t have toxicity to the lenalidomide. Pomalidomide is tolerated a little better than lenalidomide. I prefer it when they do have relapse. I tend to do that even if they’ve been off lenalidomide for a while.

 It’s been my experience that there may be more neutropenia, where I don’t know if it’s compared with lenalidomide. But when you use pomalidomide with daratumumab, for example, that can be a bit of a challenge. Anybody else want to comment?

 Yes, I agree with what Tom says. A lot of people who are on long-term lenalidomide hate the GI [gastrointestinal] adverse effects: chronic surprise diarrhea and things like that. Pomalidomide really doesn’t seem to have that. A lot of patients appreciate that. If I have a patient who’s had a long-term response on lenalidomide maintenance after a transplant and then stopped maintenance, and they start to have a biochemical relapse, those are people I will give lenalidomide again to.

 Most of us want to use the most active drug. Pomalyst is certainly more active than lenalidomide. Now we have the new CELMoDs [CRBN modulating agents]. The worry used to be, what are you going to do next? We have really active CELMoDs coming down the pike. So I would go to pomalidomide.

 A CELMoD is a third-generation version of thalidomide-lenalidomide-pomalidomide, with maybe some slightly different biological effects. But there are some very potent ones out there in clinical trials. Iberdomide is the 1 we’ve heard the most about, showing some activity even in people who’ve failed pomalidomide. Pomalidomide sounds like a good choice. What else have you combined it with, Natalie?

 Based on the OPTIMISMM trial, we use some Velcade. I know you mentioned that people aren’t using Velcade. We will give pomalidomide with Velcade, typically in a person who hasn’t had previous neuropathy. One of the regimens that we’ve used in older people, and I don’t know if other people have done this, is an old [Antonio] Palumbo regimen: pomalidomide with oral cyclophosphamide and prednisone, which is a triplet regimen you can give older patients. It’s very well tolerated.

 The data with elotuzumab-pomalidomide-dexamethasone are quite good. There’s a clear difference in overall response and a very significant difference in median progression-free survival with the addition of the elotuzumab. As Tom alluded to before, the toxicity profile of elotuzumab is quite favorable. The challenge with elotuzumab-pomalidomide-dexamethasone is that it’s unclear what its activity is and what its role is going to be in a post-CD38 antibody world, which is where most of us are using it. Anecdotally, my experience with elotuzumab-pomalidomide-dexamethasone in daratumumab-refractory patients has been suboptimal.

 We’ve concluded that pomalidomide can be combined with a number of different drugs. It seems to be the IMiD [immunomodulatory imide drug] of choice at relapse among the group, and it’s pretty active and certainly a good choice in this situation.

Lenalidomide-Refractory Multiple Myeloma

 It sounds like more and more of our patients might start getting daratumumab up front as part of their induction therapy, particularly those who are not so fit. For patients on daratumumab in the past, would you use it again, or would you switch to cetuximab?

 It depends on the length of administration when you give it for induction in maintenance-based therapy. For the GRIFFIN trial, Peter said that daratumumab is stopped at 2 years and then patients continue lenalidomide. They may be on lenalidomide for 2, 3, or 4 more years before they have disease relapse. In that scenario, those patients are for sure, in my mind, CD38 sensitive. For this patient, I would be fine putting them on isatuximab plus pomalidomide. I’d probably put them on daratumumab plus pomalidomide. If they were on a CD38 when they progressed and when they relapsed, then going from 1 CD38 to the other is not going to be an effective strategy, so I wouldn’t recommend that.

 I agree completely with what he’s saying.

 It’s very reasonable. [Winship Cancer Institute of] Emory [University] has presented data about going back and using daratumumab specifically with carfilzomib in people who previously even progressed on daratumumab. They still had a response rate that was respectable in the sort of 27%, 28% range. I would agree with Tom that somebody who’s progressing very quickly on an anti-CD38 antibody probably isn’t going to benefit from either.

 I want to challenge you all on your choice. We’ve talked about using pomalidomide in a lenalidomide-refractory.But there are a couple of trials now suggesting that you can combine carfilzomib with daratumumab and have an IMiD [immunomodulatory imide drug]–sparing regimen in those patients. I’m going to go with the person I think is least likely to think that, which is Noopur.

Sorry. I like that combination, Keith. The carfilzomib-daratumumab combination is great. The initial challenge was giving 2 IV [intravenous] drugs, the duration of the treatment when we started split-dose daratumumab. Just this past week, we’ve started using subcutaneous daratumumab as well. That makes it even more convenient. In patients who have very aggressive disease and where you want really good responses quickly, I have absolutely used carfilzomib and daratumumab. The data looked quite good.

 I want to make sure we recognize that at the European Hematology Association [Congress] that Phillipe Moreau presented data from isatuximab, also with carfilzomib, the IKEMA trial.

With the IKEMA trial, there was a significant advantage to the triplet isatuximab plus carfilzomib and dexamethasone versus the doublet carfilzomib-dexamethasone. The hazard ratio is quite low, 0.5. That was the best hazard ratio for an isatuximab study. It looked very promising too. But I agree with you. That is a great regimen for the patients who have lenalidomide-refractory disease.

Just to add, there is a subset of patients who just don’t do well on an IMiD. In that patient population, this combination is actually useful.

 Or they can’t get access to an IMiD for financial reasons or insurance problems.

 We have 2 big trials now: the CANDOR study, which was carfilzomib and daratumumab vs carfilzomib and dexamethasone alone; and the study that Tom just mentioned from Dr Moreau presented of isatuximab, carfilzomib, and dexamethasone vs carfilzomib-dexamethasone. Both positive studies for progression-free survival, both show reasonable tolerability. One thing is they both use carfilzomib, in the conventional way, which is somewhat inconvenient for patients. Many people are still using twice-weekly carfilzomib, and many are using weekly dosing.

: I’m using weekly carfilzomib exclusively at this point. When using it with daratumumab, I use the 70 mg/m2 weekly dose.

 Have you had any challenges with that in terms of toxicity?

 There isn’t any significant difference in toxicity relative to the twice-weekly. The ARROW study would support that.

 We use weekly carfilzomib most often at 56 than 70 mg/m2. You know, the ARROW study obviously is out there. But we only use twice a week if a study requires it.

 The dosing of carfilzomib depends on the backbone. If it’s cyclophosphamide or daratumumab based, I use the 70 mg/m2. But if it’s IMiD based, I’ll use a 56 mg/m2 weekly dose.

 What we’re saying in summary is that there are alternatives for lenalidomide-refractory or intolerant patients, which combine 2 of our most active drugs, an anti-CD30 antibody with a very active proteasome inhibitor.

Daratumumab With Carfilzomib in Frontline Multiple Myeloma

How about the treatment of patients with relapsed or refractory myeloma, can you provide some key updates on recent data and practice patterns? Tom, let me start with you. What principles do you use when you’re selecting your relapse therapy or subsequent therapy after induction?

 There are 3 things that I consider. First is, what are their current and residual toxicities or comorbidities that I must worry about when choosing the regimen? The second is what have they been on in the past and what they may be either refractory to or what I think they may be most sensitive to. And then the third, which is part of the patient’s part of this, is convenience, is which one, can they come to the center relatively easily to get a subcutaneous injection or to get an IV [intravenous] medication? That’s how I choose it. If there’s a fourth thing, it’s how they present. If they present aggressive, then I know I have to choose a regimen that’s going to provide a substantial improvement in their aggressive disease.

 In terms of your thinking around the course that you’re going to pursue with that patient, is a second transplant on your radar? Or are you committing to long-term use of a relapse regimen?

 I’m not a big fan of second transplants right out of the gate in first and second relapse. Some of the salvage regimens that we have provide a significant progression-free survival [PFS] advantage, without having to use a transplant. For me, it’s a triplet-based regimen and not a transplant at that time.

 Peter, let’s assume our patient has had what we just all described as standard of care, which is VRd [bortezomib, lenalidomide, dexamethasone], transplant, and lenalidomide maintenance. Now they’re progressing on lenalidomide. What are you doing for those patients? What’s your choice of regimen, assuming that they’re eligible to come into the hospital and everything else?

 The 2 regimens that are the most attractive in this situation would be daratumumab, pomalidomide, dexamethasone, and daratumumab, carfilzomib, dexamethasone, given the biologic rationale of incorporating an IMiD [immunomodulatory drug]with a monoclonal antibody. A lot of us gravitate toward the daratumumab, pomalidomide, dexamethasone triplet over the daratumumab, carfilzomib, dexamethasone triplet. It would be very interesting to do a randomized trial of this exact patient population comparing the two. I think that they would both perform very well.

 You’re sticking with an IMiD, even though they’ve just progressed on lenalidomide.

 We have good data that pomalidomide has activity in lenalidomide-refractory patients, even when they’ve become refractory in their most recent line of therapy.

 That would be pomalidomide, dexamethasone doublet in patients with lenalidomide refractory disease, whether the lenalidomide refractoriness is on the most recent therapy or previous, there is a benefit to pomalidomide, dexamethasone in that situation.

 I want to highlight Pete’s trial for Alliance. That’s going to be interesting when those results come out. He’s looking specifically at patients progressing on lenalidomide maintenance and then randomizing them to pomalidomide, dexamethasone versus pomalidomide, ixazomib, dexamethasone. Those results will be interesting as to whether they can show a triplet is the better move at that point. And these are patients who largely have indolent relapses more or less, biochemical type?

 Yes. This is biochemical progression and with a crossover.

 I do put a lot of patients on Pete’s trials. Ones with the biochemical progression. Most of us would turn to a pomalidomide-based regimen because the data do suggest that it does work in lenalidomide-refractory patients. The partner to the pomalidomide is largely dictated by the nature of the relapse. If we have somebody with high-risk features, aggressive relapse, that’s where I would reach out to the carfilzomib, pomalidomide, dexamethasone combination. And if not, then you could choose between pomalidomide, daratumumab, dexamethasone, which is an effective treatment. And more of those indolent relapses is where I would use Pete’s Alliance trial.

 I do think there’s a lot of regimens that can be used with pomalidomide, dexamethasone as a backbone. We’ve shown many studies. There’s also elotuzumab with pomalidomide, dexamethasone. And sometimes we choose that in patients who may be frailer. The infusion reaction rate is only 10%, which is great. It’s a well-tolerated drug. And the other thing I’ll mention is isatuximab. The other CD38 that now is approved for use is isatuximab, together with pomalidomide and dexamethasone. And if you look at the subset of patients who are lenalidomide-refractory in a subgroup analysis, they still do well on the isatuximab, pomalidomide, dexamethasone versus pomalidomide, dexamethasone. The triplet does better than the doublet. 

Natalie S. Callander, MD, University of Wisconsin School of Medicine and Public Health

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