AnaptysBio announced that its Board of Directors has approved plans to explore separating the clinical-stage biotechnology company into two independent, publicly traded entities by year-end 2026. The strategic restructuring aims to unlock value by creating distinct investment opportunities aligned with different business models and growth trajectories.
"Anaptys is strategically positioned with multiple attractive, high-potential assets, including our development-stage pipeline consisting of rosnilimab, ANB033 and ANB101, as well as substantial potential royalties and milestones payments from our ongoing financial collaborations with GSK and Vanda," said Daniel Faga, president and chief executive officer of AnaptysBio.
Royalty Management Company Structure
The royalty management entity will hold rights to substantial revenue streams from two key partnerships. The primary asset involves Jemperli (dostarlimab-gxly) royalties from GSK, which reported strong commercial performance with $262 million in Q2 2025 sales and $482 million in first-half 2025 sales, representing greater than 19% quarter-over-quarter growth in USD.
GSK maintains peak sales guidance of more than £2 billion (approximately $2.7 billion) for Jemperli in monotherapy indications as of September 2025. The financial collaboration provides escalating royalty rates: 8% of net sales up to $1 billion, 12% between $1 billion and $1.5 billion, 20% between $1.5 billion and $2.5 billion, and 25% above $2.5 billion. Patent protection extends through 2035 in the U.S. and 2036 in the EU.
Currently, Jemperli receivables are payable to Sagard due to prior monetization agreements, with AnaptysBio estimating Sagard will accrue $250 million in royalties and sales milestones through year-end 2025. The company anticipates full paydown of $600 million to Sagard between mid-2027 and Q2 2028.
The second royalty stream involves imsidolimab from Vanda Pharmaceuticals, providing up to $35 million in future sales milestones and regulatory approvals, including $5 million upon U.S. FDA approval, plus 10% royalties on net sales. Vanda anticipates FDA BLA submission for generalized pustular psoriasis in the second half of 2025.
Biopharma Operations Focus
The biopharma company will concentrate on developing three immunology therapeutics for autoimmune and inflammatory diseases. The lead program, rosnilimab, is a pathogenic T cell depleter that completed a successful Phase 2b trial in rheumatoid arthritis and is currently in Phase 2 testing for ulcerative colitis, with top-line data through Week 12 expected in November or December 2025.
AnaptysBio is evaluating multiple strategic options for rosnilimab, including securing a global partnership for development across all indications or independently advancing into Phase 3 for ulcerative colitis. The assessment outcome could impact how rosnilimab's economic value is allocated between the two companies.
ANB033, described as a potentially best-in-class CD122 antagonist, targets the common beta subunit of IL-15 and IL-2 to reduce NK cells and cytotoxic T cell subsets. The company has initiated a Phase 1b cohort in celiac disease as the initial indication.
ANB101, a BDCA2 modulator, targets plasmacytoid dendritic cells and inhibits interferon secretion while modulating antigen presentation. This candidate is currently in Phase 1a trials in healthy volunteers.
Ongoing Jemperli Development Pipeline
GSK continues expanding Jemperli's clinical footprint through multiple registrational and proof-of-concept studies. The AZUR-1 pivotal Phase 2 trial in untreated stage II/III dMMR/MSI-H locally advanced rectal cancer has received FDA Breakthrough Therapy Designation, with top-line data expected in the second half of 2026.
Additional ongoing studies include AZUR-2, a pivotal Phase 3 trial in untreated stage III dMMR/MSI-H resectable colon cancer, AZUR-4 Phase 2 in stage III MMRp/MSS resectable colon cancer, and JADE pivotal Phase 3 in locally advanced unresected head and neck squamous cell carcinoma.
Transaction Details and Timeline
Daniel Faga is anticipated to serve as CEO of the biopharma operations company following separation. The royalty management entity will require minimal infrastructure and staff while retaining AnaptysBio's net operating loss carryforwards. Both companies will operate under new names upon completion.
The separation is subject to final Board approval and customary conditions, including SEC registration statement effectiveness. While anticipated to be a taxable event, AnaptysBio aims to minimize corporate and shareholder-level taxes. Paul, Weiss, Rifkind, Wharton & Garrison LLP serves as legal adviser for the transaction.
