Encouraging interim phase I data for FT516 and FT538 cellular products to treat R/R AML

FT516 and FT538 are two induced pluripotent stem cell (iPSC)-derived cell therapies currently under investigation in phase I clinical trials for the treatment of relapsed/refractory (R/R) acute myeloid leukemia (AML). FT516 is an off-the-shelf natural killer cell immunotherapy administered as monotherapy. FT538 is the first CRISPR-edited iPSC-derived therapy, and its investigational new drug (IND) application has recently been cleared by the U.S. Food and Drug Administration (FDA) as a new monotherapy for patients with AML and as a combination therapy with daratumumab for the treatment of multiple myeloma.

Recently, an update with a cutoff date of April 16, 2021, on two phase I dose-escalation studies evaluating FT516 and FT538 as monotherapies to treat patients with R/R AML was published.¹

The ongoing phase I dose-escalation study of FT516 resulted in:

• three complete remissions with incomplete hematologic recovery, including one study subject that successfully proceeded to allogeneic stem cell transplantation; and
• one morphologic leukemia-free state.

For the FT538 study, three patients were enrolled in the first dose cohort of 100 million cells per dose. The results achieved included:

• one complete remission with incomplete hematologic recovery.

Across these studies, an objective response with complete leukemic blast clearance in the bone marrow was achieved for five of the twelve patients enrolled.

In both trials there were no cases of dose-limiting toxicity, cytokine release syndrome (any grade), immune effector cell-associated neurotoxicity syndrome, or graft-versus-host disease. Overall, the interim data suggest that these novel monotherapies could potentially help patients with R/R AML to achieve durable remissions and complete leukemic blast clearance without further therapeutic interventions and with limited side effects.