SEATTLE, WA — September 16, 2025 — Leads & Copy — Aptevo Therapeutics (NASDAQ:APVO) announced a 100% remission rate in Cohort 3 of its Phase 1b/2 RAINIER trial. The trial is evaluating mipletamig, Aptevo’s CD123 x CD3 bispecific antibody, in combination with venetoclax + azacitidine for newly diagnosed patients with acute myeloid leukemia (AML) unfit for intensive chemotherapy.
Aptevo also reported that no dose-limiting toxicities or cytokine release syndrome have been observed in the RAINIER trial, or among any frontline patients treated with mipletamig to date. Cohort 4 is now open for enrollment.
According to Marvin White, President and Chief Executive Officer of Aptevo, the Cohort 3 results demonstrate the kind of progress that changes expectations for frontline AML therapy. Dirk Huebner, MD, Chief Medical Officer, said that across the RAINIER trial to date, mipletamig has achieved near-universal remissions while maintaining a safety profile that is very well managed in the clinic.
Mipletamig is Aptevo’s lead drug candidate and is being evaluated for the treatment of AML.
Miriam Weber Miller
Aptevo Therapeutics
IR@apvo.com or millerm@apvo.com
+1 (206) 859 662
Source: Aptevo Therapeutics
