Aptevo Advances Next-Generation Trispecific Candidate Toward Clinical Development

SEATTLE, WA / ACCESS Newswire / September 24, 2026 / Aptevo Therapeutics Inc. ("Aptevo" or the "Company") (Nasdaq:APVO), a clinical-stage biotechnology company developing novel multispecific immuno-oncology therapeutics based on its proprietary ADAPTIR™ and ADAPTIR-FLEX™ platform technologies, today announced progress in its next-generation trispecific programs. The Company is optimizing several trispecific candidates for reliable, scalable manufacturing, an essential step toward future human testing. Aptevo expects to enter Investigational New Drug ("IND") enabling studies for the lead candidate, APVO451, in 1H2027.

Trispecific therapies are gaining attention across cancer drug development as researchers explore their potential to bring multiple complementary functions together in a single molecule. Trispecifics are engineered to do more than traditional antibody therapies. Each molecule can combine three complementary functions to recognize cancer, activate an immune attack and help overcome defenses that cancer uses to survive. Aptevo's protein-engineering and process development expertise makes it possible to bring these carefully selected functions together in one stable molecule and create differentiated therapies for specific cancers.