Correction: JJP Biologics Announces Positive Top-Line Phase I Trial Results of JJP-1212, its anti-CD89 antagonist

• Favorable safety, tolerability, pharmacokinetic and pharmacodynamic profiles validate and significantly de-risk the program
• Supports the feasibility of intravenous and subcutaneous dosing regimens in upcoming clinical development stages
• Confirms JJP-1212 as a versatile antibody with potential for use across multiple immune-mediated indications in which IgA contributes to disease pathology
  
  

Warsaw, Poland – January 7, 2026 – JJP Biologics, a clinical-stage biotechnology company that specializes in the development of innovative biologics, today announces positive top-line results from its Phase I clinical trial of JJP-1212, a potential first-in-class anti-CD89 antagonist that is being developed to treat autoimmune, inflammatory, and fibrotic diseases where pathogenic IgA autoantibodies are a key part of the disease mechanism.

The trial (EudraCT: 2023-508661-33-00) was a randomized, double-blind, and placebo-controlled study designed to evaluate the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of JJP-1212 in healthy volunteers. Both the single and multiple ascending dose parts were successfully completed.

All primary endpoints of the trial were met. Unblinded statistical analysis demonstrated a favorable outcome with regards to the safety and tolerability profile of JJP-1212:

• No dose-limiting toxicities were observed across the dose levels tested
• Adverse events were reported to be mild-to-moderate
• Laboratory safety parameters demonstrated no clinically significant abnormalities
• Favorable PK profile with a typical monoclonal antibody half-life of approximately three weeks

Receptor occupancy data confirmed target engagement and that the PD effect is both predictable and reversible, validating the mechanism of action of JJP-1212.

Pawel Szczepański, Chief Executive Officer at JJP Biologics, said: “These positive top-line Phase I results for JJP-1212, our lead asset, represent a significant milestone for JJP Biologics, strongly validating our innovative approach to targeting CD89 in autoimmune diseases. We are making great progress and, following this key data milestone in healthy volunteers, we look forward to reporting the next set of results from our Phase 1b trial in Linear IgA Disease in Q1 2026 and initiating a broad clinical program of Phase 2 trials by Q3 2026.”

Sohail Ahmed, MD, MBA, Chief Medical Officer at JJP Biologics, added: “The favorable safety profile and predictable pharmacological parameters from our Phase I trial significantly de-risk the JJP-1212 program and reinforce our confidence in this promising anti-CD89 antagonist's potential across multiple IgA-mediated diseases. Importantly, this targeted mechanism offers the possibility for patients with autoimmune, inflammatory, and fibrotic diseases to achieve meaningful disease control while avoiding the broad immunosuppression associated with current treatments.”

In addition to the safety profile established in healthy volunteers, JJP Biologics is actively investigating the therapeutic potential of JJP-1212 in an international, open-label cohort of patients with Linear IgA Disease, a rare immune-mediated blistering skin disease. The objectives of the trial are focused on safety, immunogenicity, tolerability, and early signs of efficacy in this target population. The initial patients have received three doses of JJP-1212, with emerging data demonstrating promising safety and efficacy.

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For further information from JJP Biologics, please contact:

JJP Biologics Paweł Szczepanski, Chief Executive Officer / Chairman of the Management Board

info@jjpbiologics.com

About JJP Biologics

JJP Biologics is a clinical-stage biotechnology company that specializes in the development of innovative biologics. JJP Biologics is driven by its mission “to find safe and effective medicines addressing the unmet needs of patients for whom we believe we can do better”. JJP Biologics is a privately funded biotech which pursues the development of its own product candidates as well as projects executed in cooperation with scientific partners. The company’s programs target general immune pathways that have application in autoimmune diseases and cancer. JJP Biologics currently has a range of programs including the most advanced JJP-1212 program for autoimmunity and JJP-1008 program for immune-oncology. For more information visit: https://jjp.bio and join the #smartgoose community by following us on LinkedIn.

About JJP-1212

JJP-1212 is a first-in-class IgG4-κ CD89 antagonist that is being developed to treat a wide range of autoimmune, inflammatory, and fibrotic diseases where IgA antibodies are known to have significant pathogenic involvement (e.g., rheumatoid arthritis, systemic lupus erythematosus, idiopathic pulmonary fibrosis, dermatitis herpetiformis, inflammatory bowel disease, IgA nephropathy, and IgA vasculitis). JJP-1212 was designated an Orphan Medicinal Product in October 2022 by the European Commission for the treatment of Linear IgA Disease. An open-label trial with JJP-1212 for this indication is ongoing.