Ouro Medicines Initiates Phase 1b Trial of OM336 in Autoimmune Cytopenias Following FDA Orphan Drug Designation
核心洞察
Ouro Medicines (搜索) has launched a Phase 1b basket study of OM336, a BCMAxCD3 T cell engager, in autoimmune hemolytic anemia (搜索) and immune thrombocytopenia (搜索) across sites in the U.S. and Australia.
The FDA granted OM336 Orphan Drug Designation for autoimmune hemolytic anemia (搜索) treatment, providing regulatory benefits including seven years of marketing exclusivity.
Previous case reports published in The New England Journal of Medicine showed two patients with relapsed/refractory AIHA achieved sustained remissions lasting at least six months without ongoing immunosuppression.
Ouro Medicines (搜索) has initiated a multi-national Phase 1b clinical study of OM336, a BCMAxCD3 T cell engager antibody candidate, in patients with autoimmune hemolytic anemia (搜索) (AIHA) and immune thrombocytopenia (搜索) (ITP). The biotechnology company also announced that the U.S. Food and Drug Administration (搜索) has granted OM336 Orphan Drug Designation for the treatment of AIHA, providing regulatory advantages including seven years of marketing exclusivity.
The open-label, multi-site study will evaluate the safety, tolerability and pharmacokinetics of OM336 in adult participants with active autoimmune cytopenias (搜索), specifically relapsed/refractory AIHA, ITP or both conditions. Sites in the United States and Australia are participating in the trial, with initial results expected in 2026.
Clinical Development Strategy
"For patients living with severe and potentially life-threatening autoimmune cytopenias (搜索) 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 (搜索). "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."
The study follows promising case reports published in The New England Journal of Medicine showing rapid and sustained remissions in two patients with AIHA extending to at least month six. Both patients had relapsed/refractory AIHA that had failed multiple treatments including glucocorticoids (搜索), splenectomy, anti-CD20 antibody (搜索), BTK inhibitor (搜索), and CD19 (搜索)-directed CAR T cell therapy.
Trial Design and Endpoints
OM336 will be administered via subcutaneous injection in ascending dose cohorts, with the primary endpoint evaluated at Week 12. Exploratory endpoints include clinical efficacy measures and blood biomarkers. The study is registered under NCT07083960.
In the published case reports, hemoglobin and other laboratory parameters normalized within one month of starting OM336, and patients remained in sustained remission off all immunosuppressive therapies through six months after study start. No blood transfusions were administered, and there were no events of Cytokine Release Syndrome (CRS), Immune-Effector Cell-Associated Neurotoxicity Syndrome (ICANS), or infection.
Drug Design and Mechanism
OM336 is designed as a BCMAxCD3 bispecific antibody that potently induces T cell-dependent cellular cytotoxicity of target cells expressing BCMA (搜索). The drug features a CD3 (搜索)-targeting arm engineered for reduced T cell cytokine induction, referred to as a "detuned" CD3-targeting arm, designed to avoid severe immune activation while retaining potency for target cell depletion.
"We believe that OM336 may provide a potentially transformative therapeutic option for a wide range of immune-mediated diseases, including active autoimmune cytopenias (搜索)," said Neely Mozaffarian, M.D., Ph.D., CMO of Ouro Medicines (搜索). "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."
Clinical Experience and Safety Profile
More than 80 patients have been dosed with OM336 across six investigator-initiated and company-sponsored clinical trials covering multiple indications, including multiple myeloma (搜索), autoimmune hemolytic anemia (搜索), immune thrombocytopenia (搜索) and autoimmune bullous diseases (搜索). The drug's long half-life enables subcutaneous dosing, allowing broader patient access through ease of administration.
Disease Background and Unmet Need
Autoimmune cytopenias (搜索) are autoimmune disorders resulting primarily from autoantibody-mediated destruction of blood cells. AIHA affects red blood cells through autoantibodies that lead to premature destruction, causing symptoms including debilitating fatigue, thromboembolism, dizziness, palpitations and shortness of breath. ITP occurs when the immune system attacks platelets, leading to low platelet count, purpura and potentially life-threatening hemorrhagic episodes.
Regulatory Benefits
The FDA Orphan Drug Designation program advances therapeutics for diseases affecting fewer than 200,000 people in the U.S., providing benefits including tax credits, exemptions from certain FDA fees and seven years of marketing exclusivity following approval, which runs concurrently with any twelve-year reference product exclusivity.