ANAPTYSBIO, INC

Busi ness Overview We are a clinical-stage biotechnology company focused on delivering innovative immunology therapeutics for autoimmune and inflammatory diseases. Our clinical-stage pipeline includes rosnilimab, a selective pathogenic T cell depleter, for which we completed a Phase 2b trial for the treatment of moderate-to-severe rheumatoid arthritis ( RA ), ANB033, a CD122 antagonist, in a Phase 1b trial for celiac disease ( CeD ) and eosinophilic esophagitis ( EoE ), and ANB101, a BDCA2 modulator, in a Phase 1a trial. We also discovered and out-licensed, in financial collaborations, multiple therapeutic antibodies, including a PD-1 antagonist (Jemperli (dostarlimab-gxly) or Jemperli ) to GSK and an IL-36R antagonist (imsidolimab) to Vanda Pharmaceuticals Inc. ( Vanda ). We currently recognize revenue from milestones and royalties achieved under our immuno-oncology collaboration with GSK and license and transition services revenue from our collaboration with Vanda. Intention to Separate Company In September 2025, we announced that our board of directors ( Board of Directors ) approved plans to explore separating our business into two independent, publicly traded companies. One company is expected to hold and continue to manage the financial collaboration for Jemperli from GSK and for imsidolimab from Vanda, with a focus on protecting and returning value of the royalties to its shareholders.