Aptevo Therapeutics announces data from Phase 1b trial of APVO436

Aptevo Therapeutics announced that APVO436, in combination with venetoclax and azacitidine, achieved a 100% clinical benefit rate in venetoclax treatment naive AML patients. The data, which was presented in a poster session at the 64th American Society of Hematology Annual Meeting and Exposition in New Orleans, also showed that APVO436, when given in combination with this standard-of-care regimen, was observed to be generally safe and well tolerated. Aptevo plans to initiate a Phase 2 trial in the second half of 2023 to further evaluate APVO436 in combination with venetoclax and azacitidine among frontline and relapsed/refractory AML patients who are venetoclax treatment naive. In the Phase 1b trial cohort 2, a total of 16 response-evaluable patients received the combination therapy of venetoclax and azacitidine with APVO436 and 75% experienced clinical benefit. 100% of patients in this cohort who had not received venetoclax previously, experienced clinical benefit; a favorable outcome with respect to a variety of response categories including CR, CRi and MLFS. The combination of venetoclax and azacitidine with APVO436 in venetoclax treatment naive response-evaluable patients in cohort 2 outperformed a composite benchmark across all clinical benefit categories. Aptevo’s ongoing Phase 1b expansion trial in both combination and monotherapy, will enroll adult patients with AML, at different disease stages, into five different cohorts of up to approximately 18 patients each. Current results are being reported for combination cohorts 1 and 2, and monotherapy cohorts 3 and 5. Trial enrollment for cohort 3 is ongoing while enrollment for cohorts 1 and 2 has finished. Additional data and observations include the following: Clinical activity was observed in both monotherapy and combination cohorts; Monotherapy activity observed in cohort 3; APVO436 Safety: APVO436 has been observed to be generally well tolerated in both combination therapy and monotherapy; CRS was observed in fewer than one-quarter of patients within the safety population and in most cases was mild or moderate and was manageable in the clinic; Side effects were generally manageable and resolved while patients remained on treatment