Zentalis discontinuing development of ZN-d5

Zentalis is disclosing that it is no longer developing the combination of its BCL-2 inhibitor, ZN-d5, with azenosertib, and is discontinuing development of ZN-d5. The combination of ZN-d5 and azenosertib was studied in 27 patients with R/R AML in a Phase 1 study. Thirteen patients were evaluable for efficacy, and the other 14 patients experienced progressive disease prior to efficacy evaluation or withdrew. The combination demonstrated clinical activity in patients who had been previously treated with venetoclax. Of the 6 patients who completed at least two cycles of therapy and underwent a cycle 3, day 1 bone marrow aspirate: 1 achieved a complete remission with incomplete hematologic recovery and became transplant eligible, 2 patients had decreased BM blast counts, 2 had stable BM blasts, and 1 patient had increased BM blasts. The safety profile was manageable and in-line with other combinations in the R/R AML disease setting.