Aptevo Therapeutics slumped 17.3% in pre-market trading to $2.15 after investors weighed strong clinical trial results against looming dilution risks.
The biotech reported encouraging Phase 1b/2 data for its mipletamig triplet therapy in frontline acute myeloid leukemia patients with TP53 mutations. Among 14 evaluable patients, the therapy achieved a 93% clinical benefit rate, with 11 patients reaching complete remission or complete remission with incomplete hematologic recovery. This translated to a 79% remission rate, significantly exceeding the historical benchmark of 41%.
Despite the positive medical outcome, the stock faced pressure from potential dilution tied to an August 2026 warrant inducement and a private investment in public equity (PIPE) financing. These arrangements created the possibility of more than 6.4 million new shares entering the market through a resale registration statement, a figure that exceeds the roughly 1.8 million shares outstanding as of late August.
The broader market showed mixed performance, with the S&P 500 up 0.3%, the Dow Jones Industrial Average gaining 0.6%, and the Nasdaq Composite rising 0.1%. Aptevo’s shares have traded between a 52-week high of $48.78 and a low of $2.30.
