Gabriela S. Hobbs, MD
A hot topic in the treatment landscape of chronic myeloid leukemia (CML) is the possibility of discontinuing the use of tyrosine kinase inhibitors (TKIs). The first TKI, imatinib (Gleevec), was approved by the FDA in 2001, and now there are many others approved in the field. However, data now supports the idea of discontinuing this treatment altogether in some patients with CML.
While the side effects of these agents are very low-grade, they can create a burden on the patient. While recent data, acknowledged by the NCCN, supports discontinuation of TKIs, there is still not enough data on the long-term effects of discontinuing a patient's treatment.
If a physician should choose this route for their patient, it is important that they follow up with them regularly, which can result in frequent visits and copays, leading to financial toxicity. Additionally, Gabriela S. Hobbs, MD, says that there is not enough data demonstrating that it is safe to discontinue treatment with a TKI and then put them back on a TKI after relapse.
In an interview with OncLive
at the 2nd Annual Live Medical Crossfire: Hematologic Malignancies, Hobbs, clinical director, Leukemia Service, Massachusetts General Hospital, discussed how discontinuing TKIs will change the treatment landscape and other strategies for treating patients with CML.
OncLive: Today, you're discussing treatment options for patients with CML. What is the current treatment landscape in this disease?
: CML is a disease that has seen a tremendous amount of progress in the last 2 decades. The biggest breakthrough was in 2001 with the approval of the first TKI, imatinib, and since then there has been several others approved. Now, you can say that therapies have become so good and so successful at treating CML that the biggest thing in the last couple of years has been the discontinuation of these medications. The main focus of this talk is who can safely stop these drugs, how does that affect patients, and how does that affect the economics of treating this disease.
When you think about the landscape of CML, you think about which drugs to try for the patient, and not just thinking about a drug that will be successful in controlling their disease, but also in giving them the possibility of not having to take these medications at some point. This is a huge shift in the way we think about CML.
Has there been any promising data in CML to come out recently?
The most exciting thing to come out recently was a big change in the NCCN guidelines. As you know, the NCCN guidelines are the guidelines that many physicians follow in the United States, but also internationally, to help treat and manage their patients. The NCCN guidelines are very helpful in managing CML. What's been exciting recently is that there's been so much data to support the idea of TKI discontinuation that the NCCN guidelines, as well as the European Leukemia Net Guidelines (ELN), now have acknowledged all those data and have incorporated that into the guidelines. They have taken into account the results of a variety of different clinical trials, including the Stop Imatinib (STIM) data, which are several trials looking at imatinib discontinuation. TWISTER data and the Dasatinib Discontinuation (DADI) study are some of the studies that have been published in the last couple of years that basically all say the same thing-that it's safe to discontinue the use of TKIs if done properly.
What are some challenges you think we still need to overcome in this field?
There are still some things I think we need to overcome, although CML is a disease for which patients have a variety of treatment options and for the most part, patients do very, very well. There are still a few things that require some improvement. Some of it can be overcome with the TKI discontinuation, but it's not for everybody. Patients still have to take a pill every day, and while that may not seem like a big deal, these drugs are not free of side effects. Many times, patients live with these diseases and they have to have these kind of low-grade, nagging side effects indefinitely, so that's really difficult. Some patients don't have side effects, but some patients do really have a lot of side effects.