Pharma BD Deal Intelligence
Eli Lilly acquired Scorpion Therapeutics' mutant-selective PI3Kalpha inhibitor program (lead asset STX-478) for up to $2.5 billion - $1 billion upfront plus up to $1.5 billion in regulatory and sales milestones - announced at JPM25 on January 13, 2025 and closed March 14, 2025. Lilly retained only the PI3Kalpha program; Scorpion's remaining assets were spun out into Antares Therapeutics (launched June 2025 with $177M). Post-close, Lilly renamed STX-478 tersolisib (development code LY4064809). Updated Phase 1/2 PIKALO-1 data presented at ESMO 2025 (Annals of Oncology LBA26; 204 patients as of July 7, 2025) showed a 23% objective response rate with tersolisib monotherapy in PIK3CA-mutant breast cancer and a tolerability profile (hyperglycemia ~31%) favorable versus wild-type-active PI3Kalpha inhibitors, supporting the mutant-selective differentiation thesis. Lilly advanced the asset to Phase 3: PIKALO-2 (NCT07174336), a randomized placebo-controlled study of tersolisib plus a CDK4/6 inhibitor and endocrine therapy in first-line HR+/HER2- PIK3CA-mutant advanced breast cancer (n=920), began recruiting December 22, 2025, with primary completion estimated May 2029.