Aptevo Therapeutics reports early data for blood cancer therapy; shares fall

Aptevo Therapeutics

03/09/2026 14:11

** Shares of drug developer Aptevo Therapeutics fall 21.2% to $2.05 premarket 
** Co says its experimental leukemia treatment, mipletamig, achieved a 93% clinical benefit rate in frontline acute myeloid leukemia (AML) patients with TP53 mutations, a hard-to-treat patient population in an early-to-mid stage trial 
** Of 14 evaluable TP53-mutated AML patients treated with mipletamig in combination with venetoclax and azacitidine, 13 experienced clinical benefit
** Eleven patients, or 79%, achieved complete remission or complete remission with incomplete hematologic recovery, including nine complete remissions
** TP53-mutated AML is associated with poor outcomes and lower response rates than other forms of the blood cancer
** Last year, Aptevo reported a 100% remission rate in an earlier cohort of the trial
** Aptevo expects to complete the dose-optimization portion of the study by year-end and plans regulatory discussions in H1 2027
** As of last close, stock down 72.4% YTD 

 (Reporting by Siddhi Mahatole)
 ((siddhi.mahatole@thomsonreuters.com))