Aptevo’s Mipletamig Achieves 100% Remission in AML Trial, Setting New Bar for Frontline Therapy
DENVER, Colo., Sep 16, 2025 (247marketnews.com)- Aptevo Therapeutics (NASDAQ:APVO) reported striking new results from its Phase 1b/2 RAINIER trial for acute myeloid leukemia (AML), with its investigational therapy mipletamig delivering a 100% remission rate in Cohort 3. The bispecific antibody, which targets CD123 and CD3, is being tested in combination with venetoclax and azacitidine in newly diagnosed AML patients who are unfit for intensive chemotherapy.
These latest results mark a milestone not only for Aptevo, but for the broader AML treatment landscape. The remission rate, defined as complete remission or complete remission with incomplete hematologic recovery (CR/CRi), at the highest dose tested so far significantly exceeds what is typically seen with current standard-of-care regimens in this difficult-to-treat population.
Notably, 40% of patients treated to date have also achieved minimal residual disease (MRD)-negative status, an important prognostic indicator tied to longer survival and lower relapse rates. In a frontline AML market estimated in the billions, mipletamig is showing potential to not only compete, but to lead.
Perhaps just as important as its efficacy is mipletamig’s safety profile. Across three cohorts, the trial has seen no dose-limiting toxicities and no cytokine release syndrome, a common and dangerous side effect associated with many immunotherapies. This combination of potent efficacy and clean tolerability could allow the therapy to integrate more easily into existing AML treatment regimens, without the risk-management hurdles that often slow adoption of novel therapies.
Aptevo’s trial is progressing efficiently, with Cohort 4 now open for enrollment. The company has indicated that updated findings may be presented at a major medical conference later this year, a key catalyst that could raise visibility among oncologists and investors alike.
If mipletamig continues to deliver across future cohorts and in larger patient populations, it may offer a new, best-in-class option for AML patients who currently face limited and often suboptimal choices. For Aptevo, this is shaping up to be more than a promising drug, it could be a breakthrough.
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