Newly released findings from Vor Bio showcase the effective integration of their hematopoietic stem cells into the initial seven patients contending with relapsed or refractory acute myeloid leukemia. These cells have demonstrated a notable resilience against the customary toxic effects associated with antibody-drug conjugates (ADCs).
This marks an early breakthrough in employing gene-edited transfusions to alleviate the adverse effects of a two-pronged regimen, precisely targeting cancer cells while safeguarding healthy ones. Within this cohort, three patients have undergone a continuous dose of Pfizer’s Mylotarg, an approved ADC, marking the second phase of their treatment. Vor’s report highlights that these patients have experienced “hematologic protection,” indicating the potential for an increased Mylotarg dose without adverse effects.
The company is also exploring the prospect of seamlessly treating engrafted patients with a CD33-targeting allogeneic CAR-T therapy. These groundbreaking findings are slated for presentation at the upcoming annual International Conference on Relapse After Transplant and Cellular Therapy in Los Angeles.
Ang emphasizes the crucial objective of validating their core hypothesis: the elimination of CD33 from the surface of stem cells to shield them post-transfusion. Despite relapses in three of the engrafted patients, including one who received Mylotarg, the primary focus remains on confirming this hypothesis.
Should trial patients experience a relapse, they will have options for enhancing their treatment. This enhancement might involve a more frequent 0.5-mg induction course of Mylotarg or the utilization of an allogeneic version of Vor’s CAR-T therapy, VCAR33. Looking toward 2024, Ang is eager to expedite recruitment to gain a more comprehensive understanding of post-relapse treatment efficacy.
Unfortunately, the recent update from Vor Bio lacked data concerning the response rate. Nevertheless, CEO Robert Ang maintains a practical outlook regarding the potential benefits of this challenging patient group.
Given the severity of the disease, Ang concedes that most trial patients are anticipated to experience relapse, reducing the emphasis on response rate data. Ang highlighted the importance of this data, not only for Vor Bio but also for potential investors, aligning with the collective interest in robust findings.