Aktis Oncology AKY-2519 First-in-Human Imaging + Dosimetry Data: B7-H3-Targeting Miniprotein Radioconjugate Shows Robust Tumor Uptake in mCRPC and Solid Tumors (ASCO 2026)
Aktis Oncology released first-in-human clinical imaging and dosimetry data on AKY-2519 ahead of ASCO 2026. AKY-2519 is a miniprotein radioconjugate — a small synthetic protein scaffold (akin to engineered peptide architecture) linked to a therapeutic radionuclide — targeting B7-H3, an antigen overexpressed in multiple solid tumors including metastatic castration-resistant prostate cancer (mCRPC) and non-small cell lung cancer. The Phase 1 data demonstrated robust tumor uptake and limited normal-tissue exposure across multiple B7-H3-expressing tumor types. Two ASCO 2026 poster presentations cover the imaging and dosimetry results. The FDA cleared the IND for AKY-2519 in March 2026; a Phase 1b clinical trial in mCRPC patients is ongoing, with a second Phase 1b in various B7-H3-expressing tumor types expected to initiate in H2 2026. AKY-2519 joins Novartis's Pluvicto (PSMA-617) and Lutathera (DOTATATE) in the small but growing class of peptide-related radioconjugates with first-in-human or commercial validation.