Ouro Medicines Announces Initiation of OM336 Basket Study in Autoimmune Cytopenias and Granting of U.S. FDA Orphan Drug Designation for OM336 in Autoimmune Hemolytic Anemia (AIHA)

Sites in the U.S. and Australia are participating in this Phase 1b study of OM336 in autoimmune cytopenias

Initial results expected in 2026

SAN FRANCISCO, Aug. 5, 2025 /PRNewswire/ -- Ouro Medicines, a biotechnology company developing immune reset therapeutics for people living with chronic, immune-mediated diseases, today announced the initiation of a multi-national clinical study of OM336, a BCMAxCD3 T cell engager antibody candidate, in autoimmune hemolytic anemia (AIHA) and/or immune thrombocytopenia (ITP), two types of autoimmune cytopenias.

In addition, Ouro Medicines announced that OM336 has been granted U.S. Food and Drug Administration (FDA) Orphan Drug Designation (ODD) for development in the treatment of AIHA.

"For patients living with severe and potentially life-threatening autoimmune cytopenias like AIHA and ITP, current treatment options often require long-term immunosuppression with significant side effects," said Jaideep Dudani, Ph.D., CEO of Ouro Medicines. "This study represents an opportunity to explore whether OM336 can offer a fundamentally different approach: the potential to provide a state of 'immune reset' leading to durable remission without ongoing immunosuppression. This approach would represent a large improvement relative to the standard of care for patients with autoimmune cytopenias. Because of shared cellular drivers, successful treatment of patients with AIHA and ITP with OM336 could support expansion to other immune-mediated diseases."

"We believe that OM336 may provide a potentially transformative therapeutic option for a wide range of immune-mediated diseases, including active autoimmune cytopenias," said Neely Mozaffarian, M.D., Ph.D., CMO, Ouro Medicines. "A growing set of clinical data from investigator-initiated and company-sponsored studies of OM336 supports the potential utility of OM336 across B-cell driven autoimmune diseases. These data include recently published positive case reports of OM336 in relapsed/refractory AIHA. We are looking forward to gathering more data on the translational benefit of OM336's mechanism of action and unique drug design in the clinic."

Ouro announced the intention to initiate this study of OM336 in June 2025, coinciding with case reports of OM336 published in The New England Journal of Medicine showing rapid and sustained remissions in two patients with AIHA extending to at least month six. This open-label, multi-site, Phase 1b study of OM336, conducted in the U.S. and Australia, will evaluate the safety, tolerability and pharmacokinetics of OM336 in adult participants with active autoimmune cytopenias, specifically relapsed/refractory AIHA, ITP or both (NCT07083960). Exploratory endpoints include clinical efficacy measures and blood biomarkers. OM336 will be administered via subcutaneous injection in ascending dose cohorts, with the primary endpoint evaluated at Week 12.

The U.S. FDA ODD program is intended to advance therapeutics developed to treat, prevent or diagnose diseases that affect fewer than 200,000 people in the U.S. and provides benefits including tax credits, exemptions from certain FDA fees and, following approval, seven years of marketing exclusivity, which runs concurrently with any twelve year reference product exclusivity.

About OM336

OM336 is an investigational BCMAxCD3 bispecific antibody designed to potently induce T cell-dependent cellular cytotoxicity of target cells expressing BCMA. With a CD3-targeting arm engineered for reduced T cell cytokine induction also referred to as a 'detuned' CD3-targeting arm, OM336 is designed to avoid severe immune activation while retaining potency for target cell depletion, which may expand its therapeutic index. OM336 has a long half-life, which enables subcutaneous dosing allowing broader patient access through ease of administration and additional favorable properties that may contribute to safety and tolerability.

More than 80 patients have been dosed with OM336 across six investigator-initiated and company-sponsored clinical trials covering a range of indications, including multiple myeloma, autoimmune hemolytic anemia (AIHA), immune thrombocytopenia (ITP) and autoimmune bullous diseases. Case reports of OM336 in relapsed/refractory AIHA have shown normalization of laboratory parameters within one month of receiving treatment with OM336, with patients remaining in remission without immunosuppressive therapies or blood transfusions through at least six months after study start.

About Autoimmune Cytopenias

Autoimmune cytopenias are autoimmune disorders resulting primarily from autoantibody-mediated destruction of blood cells. These disorders include autoimmune hemolytic anemia (AIHA), which affects red blood cells, and immune thrombocytopenia (ITP), which affects platelets. Both indications are potentially life-threatening. In AIHA, autoantibodies lead to the premature destruction of the body's own red blood cells (known as hemolysis). Individuals living with AIHA may experience typical symptoms of anemia, including debilitating fatigue, thromboembolism, dizziness, palpitations and shortness of breath. ITP occurs when the body's immune system attacks platelets, the blood cells that help control bleeding. This can lead to low platelet count, purpura and hemorrhagic (or bleeding) episodes for patients that can be life-threatening in some cases.

About Ouro Medicines

Ouro Medicines is a biotechnology company dedicated to developing immune reset therapeutics for people living with chronic immune-mediated diseases. Ouro's approach is focused on leveraging T cell engagers in B cell mediated diseases to achieve immune resets that create durable remissions without ongoing immunosuppression. Based in San Francisco and launched in 2025, Ouro was founded by Monograph Capital in partnership with GSK. Ouro is also backed by leading investors, TPG, NEA, and Norwest. For more information visit https://www.ouromedicines.com/ or follow us on LinkedIn @ouromedicines.

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SOURCE Ouro Medicines