Mitchell E. Horwitz, MD, expands on key efficacy and safety data supporting the FDA approval of omidubicel, the significance of this decision for the blood cancer treatment paradigm, and the need for continued investigation of the agent in non-malignant disease and other patient subgroups.
The FDA approval of the first substantially modified allogeneic donor cord blood–based cell therapy omidubicel-onlv (Omisirge) provides patients with blood cancers requiring umbilical cord blood (UCB) transplantation with a viable alternative, and improves outcomes by reducing the risk of infection and time to neutrophil recovery after transplant, according to Mitchell E. Horwitz, MD.
On April 17th, 2023, the FDA approved omidubicel for both adult and pediatric patients aged 12 years and older with blood cancers who are planned to undergo UBC transplantation after myeloablative conditioning. The regulatory decision was based on findings from the phase 3 trial, Study P0501 (NCT02730299).1
Results showed that 87% of patients who received omidubicel (n = 62) achieved neutrophil recovery within a median of 12 days (95% CI, 10-14) vs 83% of those who received standard-of-care (SOC) UCB transplantation (n = 63) who achieved this at a median of 22 days (95% CI, 19-25; P < .001).1,2 Furthermore, the incidence of bacterial or fungal infections 100 days after transplantation was reduced to 39% in those who received omidubicel vs 60% in those who received UCB.
“[This study] provides ample evidence that omidubicel should be considered as a new SOC for patients who need a stem cell transplant,” said Horwitz, who is a professor of medicine at Duke University School of Medicine, a member of the Duke Cancer Institute, and an affiliate of the Duke Regeneration Center. “Further research [should] compare omidubicel with other stem cell grafts. We don’t have those data yet.”
In an interview with OncLive®, Horwitz, who is also a cellular therapy specialist and stem cell transplant specialist at Duke Health, in Durham, North Carolina, expanded on key efficacy and safety data supporting the approval of omidubicel, the significance of this decision for the treatment paradigm, and the need for continued investigation of the agent in non-malignant disease and other patient subgroups.
Horwitz: Omidubicel represents the first manipulated stem cell graft to gain approval by the FDA. It’s unprecedented to have a new stem cell graft available for our patients.
The primary end point of the study was time to neutrophil engraftment. Omidubicel showed a significant improvement in blood count recovery compared with standard UCB transplantation. For [patients who received a] standard cord blood graft, the neutrophil engraftment was approximately 22 days. For recipients of omidubicel, the time to engraftment was just 12 days, representing a statistically significant and meaningful improvement in patients recovering from the adverse effects [AEs] of allogeneic hematopoietic stem cell transplant [allo-HSCT].
Because of the rapid neutrophil engraftment, our patients who received omidubicel spent significantly less time in an inpatient setting compared with those who received standard-of-care [SOC] transplant. This was a multicenter study and practices vary quite a bit from center to center. When we looked at the time spent in the hospital for the first 100 days after transplant, the recipients of omidubicel spent, on average, 48 days in the hospital vs 61 days for those who received SOC transplantation.
The benefits of omidubicel extend beyond just neutrophil engraftment. The patients who received omidubicel saw significantly quicker platelet recovery, and experienced fewer severe bacterial and fungal infections. In an unexpected finding, the omidubicel recipients had fewer viral infections. We’re beginning to understand why that is with further studies of immune reconstitution.
Allo-HSCT is an intensive procedure with lots of AEs. We were pleased to see that there was no significant increase in short term, serious AEs compared with standard cord blood transplantation. Recently, my colleague Chenyu Lin, MD, of Duke Health, published a pooled analysis of 114 omidubicel recipients in multiple studies done during the development of this stem cell graft. This analysis showed durable hematopoietic function over time. The first recipients [of omidubicel] are now close to 12 years out from receiving their omidubicel graft. Immune competence [also] seems comparable to those receiving standard stem cell transplant.
We must stick to the population that’s been [evaluated] in multiple studies over the past 10 years. We have not yet studied omidubicel in patients who have fibrotic bone marrow. [This agent has not been] extensively studied in patients with fibrotic myelodysplastic syndrome, primary myelofibrosis, or those who developed secondary myelofibrosis. I suspect that omidubicel would work well in that population, but that must be studied further before we can confidently say that’s the case. We also haven’t studied omidubicel in the setting of reduced intensity or non-myeloablative conditioning. There’s no theoretical [reason] why it shouldn’t work [in these spaces], but the label [doesn’t include that]. Further studies are planned [for omidubicel] in those populations.
Most stem-cell transplant physicians believe that a matched donor, whether it comes from the family or from the National Marrow Donor Program Registry, is the ideal first choice for patients who need a stem cell transplant. For those who need a mismatched donor transplant, there are many options now.
The studies that have been completed in the label now suggest that omidubicel can now be considered a standard graft source for those patients. Studies over the years, and our study, have attracted many North American minority populations who don’t have other mismatched [donor] options. That will be a real benefit for our minority population of patients.
Also, our co-investigators in Singapore were quite enthusiastic about omidubicel because there is difficulty finding matched donors in their population. There are also other options, such as a haploidentical transplant graft, mismatched-unrelated donors, or even standard UCB transplantation. There are now many more options with the approval of omidubicel.
The approval of omidubicel does not include patients with non-malignant disease. My colleagues Suhag Parikh, MD, and Joanne Kurtzberg, MD, in our pediatric program at Duke Cancer Institute, have studied omidubicel in the context of stem cell transplantation for sickle-cell disease. This is a very exciting area for further exploration. It’s very hard to get mismatched stem-cell transplants to work in this population. [The ability of] omidubicel [to] provide a high stem cell dose with rapid engraftment would be very promising. They’re [planning to] follow up on the studies that have already been done [in this space].
FDA approves omidubicel to reduce time to neutrophil recovery and infection in patients with hematologic malignancies. News release. FDA. April 17, 2023. Accessed May 17, 2023. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-omidubicel-reduce-time-neutrophil-recovery-and-infection-patients-hematologic