AnaptysBio Announces Portfolio Update Across Best-in-Class Immune Cell Modulating Antibodies

• Advancing rosnilimab, its PD-1 agonist, into a global Phase 2b trial to treat rheumatoid arthritis with study initiation in Q3 2023
• Advancing ANB032, its BTLA agonist, into a global Phase 2b trial to treat atopic dermatitis with study initiation in Q2 2023
• Advancing rosnilimab into a second Phase 2 trial, in an indication to be announced, with study initiation anticipated by year-end 2023
• Blinded interim review of alopecia areata Phase 2a data demonstrated rosnilimab “proof of mechanism” with robust reductions in peripheral PD-1 high and PD-1+ T cells and suggests administration was generally safe and well tolerated; However, absolute SALT scores were not supportive of the target product profile and further development in alopecia areata will not be pursued
• Ended 2022 with greater than $575 million and approximately 4 years of capital

SAN DIEGO, Jan. 05, 2023 (GLOBE NEWSWIRE) -- AnaptysBio, Inc. (Nasdaq: ANAB), a clinical-stage biotechnology company focused on delivering innovative immunology therapeutics, today announced a portfolio update including initiating development of its wholly owned best-in-class immune cell modulating antibodies in autoimmune and inflammatory diseases with large and significantly underserved patient populations. With cash, cash equivalents and investments greater than $575 million as of December 31, 2022, the company anticipates having approximately 4 years of capital to execute against its non-risk adjusted research and development plan, excluding potential future royalties from its GSK immuno-oncology financial collaboration.

“We have continued to progress our strategic portfolio review and are excited to announce the near-term initiation of two global Phase 2b trials across rosnilimab, our PD-1 agonist, in rheumatoid arthritis and ANB032, our BTLA agonist, in atopic dermatitis. We believe their mechanisms of action, with the potential to restore immune balance by acting directly on cell types mediating disease pathology, have the potential to meaningfully impact large and significantly underserved patient populations,” said Daniel Faga, interim president and chief executive officer of AnaptysBio. “We’re well capitalized to deliver on multiple Phase 2b readouts across our wholly owned checkpoint agonists as well as to advance ANB033, our anti-CD122 antagonist, through clinical proof-of-concept.”

Rosnilimab (PD-1 agonist antibody)

• Rosnilimab, its investigational wholly owned PD-1 agonist, demonstrates best-in-class activity in vitro with superior inhibition of T cell proliferation, reduction in inflammatory cytokine secretion (Th1, Th2, Th17) and depletion of PD-1+ T cells via effector function compared to Lilly PD-1 agonist
• PD-1+ T cells are clinically validated drivers of disease in rheumatoid arthritis (RA)
  • RA patient synovial biopsies have dense T cell infiltrates, with >80% of T cells expressing PD-1 and insufficient PD-L1 expression to down-regulate T cell activity
  • Rosnilimab targets multiple distinct inflammatory mechanisms addressed by approved therapies to treat RA
• Initiation in Q3 2023 of a global Phase 2b trial in moderate-to-severe RA
  • Multi-hundred patient placebo-controlled trial assessing three dose levels of subcutaneously administered rosnilimab for approximately 6 months on well-established endpoints including ACR20/50/70 and DAS28
  • Top-line interim data anticipated by mid-year 2025
• Second global Phase 2 trial, in an indication to be announced, with study initiation anticipated by year-end 2023
• Conducted a blinded interim review of alopecia areata Phase 2a data in December 2022
  • Enrolled 51 patients in a placebo-controlled trial assessing a single 400mg Q4W dosage of subcutaneously administered rosnilimab (randomized 2:1)
  • Study remains blinded with 100% of patients (n=38) through both week 20 dosing period and week 24 primary endpoint and 61% of patients (n=18) through week 32 follow-up period
• Demonstrated rosnilimab “proof of mechanism” with robust reductions in peripheral PD-1+ T cells, including PD-1 high T cell reduction of >80%, across blinded pooled rosnilimab treated and placebo patients, which is consistent with observations in the healthy volunteer Phase 1 trial of >90% in rosnilimab treated patients
• Suggests rosnilimab administration was generally safe and well tolerated
• Severity of Alopecia Tool (SALT) scores were not supportive of achieving the target product profile and further development in alopecia areata will not be pursued
  • While select patients observed changes from baseline SALT scores at week 24, no patients achieved an absolute SALT score