Aptevo Therapeutics Surges 46% After Hours on Breakthrough AML Treatment Results

Aptevo Therapeutics Inc. (APVO) surged 46.10% to $2.06 after hours following breakthrough clinical results demonstrating its drug’s potential to redefine frontline AML treatment. The biotech company reported that all patients in Cohort 3 of its Phase 1b/2 RAINIER trial went into complete remission. Enrollment for Cohort 4 is ongoing at higher dose levels, with a conference presentation expected in Q4. The frontline AML market is a multi-billion-dollar opportunity, with current standard treatments achieving lower remission rates.

Aptevo Therapeutics Inc. (APVO) experienced a significant surge in its stock price after hours on Wednesday, September 12, 2025, following the announcement of breakthrough clinical results from its drug mipletamig. The biotech company reported that all patients in Cohort 3 of its Phase 1b/2 RAINIER trial achieved complete remission, demonstrating the potential of mipletamig to redefine frontline AML treatment Aptevo Therapeutics Surges Over 46% After Hours On Breakthrough AML Treatment Results^[1].

The trial, which tests mipletamig in combination with venetoclax and azacitidine, showed a perfect remission rate of 100% at the highest dose level, with 40% of patients achieving minimal residual disease (MRD)-negative status. No dose-limiting toxicities or cytokine release syndrome were observed across all cohorts, indicating a favorable safety profile Mipletamig Delivers 100% Remission Rate in Cohort 3 of RAINIER Trial for AML^[2].

The frontline AML market is a multi-billion-dollar opportunity, with current standard treatments achieving lower remission rates than those seen in the RAINIER trial. The 100% remission rate reported by Aptevo positions mipletamig as a potential game-changer in the treatment landscape for newly diagnosed AML patients who are unfit for intensive chemotherapy Mipletamig Delivers 100% Remission Rate in Cohort 3 of RAINIER Trial for AML^[2].

Enrollment for Cohort 4 is ongoing at higher dose levels, and the company expects to present the results at a major medical conference in the fourth quarter of 2025. This progress suggests strong investor interest and patient recruitment in the trial Mipletamig Delivers 100% Remission Rate in Cohort 3 of RAINIER Trial for AML^[2].

APVO stock surged 46.10% to $2.06 during after-hours trading, reaching a one-month peak of $2.07. Over the past year, the stock has lost 98.84%, and so far in 2025, it is down 98.36%. The stock has a market capitalization of $4.64 million and an average trading volume of 3.98 million shares Aptevo Therapeutics Surges Over 46% After Hours On Breakthrough AML Treatment Results^[1].