AnaptysBio, Inc.

Company overview

AnaptysBio is a clinical-stage biotechnology company focused on immunology therapeutics for autoimmune and inflammatory diseases. Its lead wholly owned pipeline candidates are rosnilimab, ANB033, and ANB101. The company has discovered and out-licensed additional programs, including dostarlimab (Jemperli) to GSK and imsidolimab to Vanda. Current revenue sources include collaboration milestones, royalties (GSK/Jemperli), and license and transition services (Vanda/imsidolimab).

Proposed separation into two public companies

• Announced September 2025: plan to separate into two independent public companies.
• Royalty Management Co. would hold and manage Jemperli royalties from GSK and imsidolimab royalties from Vanda.
• Biopharma Co. would be a clinical-stage company focused on rosnilimab, ANB033, and ANB101.
• Expected completion: second quarter of 2026, subject to approvals and customary closing conditions.

Wholly owned clinical-stage pipeline

Rosnilimab

• IgG1 antibody that targets pathogenic T cells (activated Tph/Tfh, Teff) with effects in peripheral blood and tissues.
• Mechanism: depletes pathogenic T cells while sparing naïve T cells to preserve immune function.
• Clinical status: Phase 2b in moderate-to-severe rheumatoid arthritis (RA) with positive results on the primary and key secondary endpoints.
• Key data: DAS-28 CRP at Week 12 improved across rosnilimab dose groups versus placebo; ACR20/50/70 and CDAI LDA showed dose-responsive signals; six-month all-active period data showed deepening responses; six-to-eight week durability off drug observed; safety profile in the trial was favorable with no SAEs attributed to rosnilimab.
• History: Top-line Phase 1 healthy volunteer data in 2021 (144 subjects across SAD and MAD cohorts, with half receiving placebo); estimated two-week half-life for SC and IV routes.

ANB033

• CD122 (shared IL-2/IL-15 receptor beta chain) antagonist antibody.
• Rationale: inhibits IL-15 and IL-2 signaling through intermediate/high-affinity IL-2 receptors to dampen pathogenic T cell subsets and ILC2s.
• Clinical status: Phase 1b in celiac disease (CeD) and eosinophilic esophagitis (EoE); global Phase 1a/1b program completed with early pharmacodynamic effects.
• Key data: Phase 1a/1b healthy volunteer data showed rapid, sustained receptor occupancy and pharmacodynamic effects; 70–75% reduction in CD122-expressing CD8 T cells; depletion of CD122-expressing NK cells without excessive overall CD8 T cell reduction; no meaningful peripheral blood Treg decline.

ANB101

• BDCA2 modulator antibody targeting plasmacytoid dendritic cells (pDCs) to inhibit interferon secretion and modulate antigen presentation.
• Rationale: pDCs are upstream drivers of inflammatory cascades; BDCA2 modulation aims to reduce interferon-driven pathology.
• Status: Phase 1 in healthy volunteers initiated March 2025; preclinical data indicate higher potency and longer half-life than the comparator antibody litifilimab.

Collaboration programs (selected)

GSK collaboration

• Jemperli (dostarlimab), a PD-1 antibody, has achieved multiple regulatory approvals in various settings, including dMMR/MSI-H cancers, with approvals broadened through 2024–2025.
• AnaptysBio receives milestone payments and tiered royalties on net sales; GSK leads ongoing development and commercialization for multiple programs under the collaboration.
• Royalty monetization: AnaptysBio monetized certain Jemperli royalties and milestones to Sagard in 2019/2021, with amendments in 2024; Sagard accrued about $250 million in royalties and milestones by year-end 2025. The monetization arrangement terminates once specified thresholds are met.
• As of October 2025, GSK terminated two additional programs (LAG-3 and TIM-3) under the collaboration; rights to those programs revert to AnaptysBio.

Vanda collaboration

• Exclusive global license to imsidolimab (IL-36R antagonist) granted January 31, 2025.
• Upfront payments: $10.0 million plus $5.0 million for drug supply; 10% royalty on net sales; additional milestone payments for US/EU regulatory approvals and commercial milestones, potentially totaling tens of millions.
• As of December 31, 2025: milestones remain outstanding; FDA accepted a BLA for imsidolimab for generalized pustular psoriasis (GPP) with an FDA action date targeted for December 12, 2026.

Intellectual property

• Patents and applications cover rosnilimab, ANB033, ANB101, dostarlimab (GSK4057190), and imsidolimab.
• BDCA2 license portfolio from Centessa (ANB101) with potential future payments and low single-digit royalties; Centessa contingent milestone potential up to $10 million as of December 31, 2025.
• Patent coverage spans the U.S. and international jurisdictions with various expiration timelines (examples: rosnilimab into the 2040s; ANB033 to ~2045; ANB101 to ~2040; dostarlimab-related patents to ~2038; imsidolimab to ~2042).

Manufacturing

• The company relies on third-party contract manufacturers for clinical and potential commercial supply, including some foreign suppliers (e.g., China).
• Clinical-trial manufacturing uses cGMP-compliant contract manufacturers. Commercial-scale supply will require additional scale-up and tech transfer.
• The company manages supply continuity, scale-up, regulatory compliance, and potential geopolitical or trade-related risks.

Financial highlights

• Collaboration revenue (fiscal year ended December 31, 2025): $234.6 million.
• Net loss for 2025: $13.2 million.
• Accumulated deficit as of December 31, 2025: $772.6 million.
• Cash, cash equivalents, and investments: sufficient to fund the current operating plan for at least the next 12 months.

Operations and corporate

• Number of employees: 104 as of January 31, 2026; 72 engaged in R&D; 33 hold MD, PhD, or PharmD degrees.
• Headquarters: San Diego, California. Principal offices at 10770 Wateridge Circle, Suite 210, San Diego, CA 92121.
• Office lease: approximately 45,000 square feet with a 124-month term.
• Incorporated in Delaware in November 2005.
• The company files periodic SEC reports (Form 10-K, 10-Q, etc.) and maintains disclosures on the SEC website and the company site.
• Corporate governance features include exclusive forum provisions for certain legal actions in Delaware.

Strategic focus

AnaptysBio advances a translational, data-driven development program with collaborations and a royalty-focused structure planned after the proposed separation. The separation plan aims to provide Biopharma Co. with capital to fund at least 12 months of operations after completion, while Royalty Management Co. would manage royalty-related assets.

Summary

AnaptysBio is a clinical-stage immunology-focused biotech with internal programs (rosnilimab, ANB033, ANB101) and active collaborations (GSK for Jemperli; Vanda for imsidolimab). The company is planning a 2026 separation into two public companies and reported 2025 collaboration-driven revenue of $234.6 million with a net loss of $13.2 million. It employed 104 people as of January 31, 2026.