AnaptysBio Completes Royalty-Only Pivot With CEO, CFO on Consulting Contracts

AnaptysBio (Nasdaq: ANAB), roughly $1.6 billion in market cap, spent more than a decade as a clinical-stage immunology company before deciding in late 2025 to split itself in two. The biopharma operations — including rosnilimab, ANB033 and ANB101 — were spun out as First Tracks Biotherapeutics (Nasdaq: TRAX) on April 20, 2026. What remained is a royalty management shell whose entire value rests on two out-licensed antibodies: dostarlimab (Jemperli), sold by GSK, and imsidolimab, licensed to Vanda Pharmaceuticals.

Jemperli is the dominant asset. Royalty rates run from 8% on net sales below $1 billion up to 25% above $2.5 billion, with GSK guiding to peak monotherapy sales of more than £2 billion ($2.7 billion). Management has projected that peak annualized royalties payable to AnaptysBio could exceed $390 million. Against that income stream sits a non-recourse royalty monetization with Sagard Healthcare Partners, carrying a remaining balance of roughly $325 million as of May 2026, with paydown expected by the end of Q2 2027.

The complication is litigation. In November 2025, AnaptysBio sued Tesaro (a GSK subsidiary) and GSK in Delaware Chancery Court, alleging Tesaro materially breached the Collaboration Agreement by running clinical trials that benefit competitor PD-1s and failing to seek the optimum commercial return for Jemperli. GSK and Tesaro filed their own counter-complaint the same day. AnaptysBio's complaint asks the court to declare Tesaro's breaches incurable and to revert all dostarlimab rights back to AnaptysBio — a remedy that would be existentially disruptive to GSK's oncology franchise if granted.