Ouro Medicines Announces a Clinical Trial of OM336 for Autoimmune Cytopenias Following Positive Case Reports in The New England Journal of Medicine

In an investigator-sponsored study of OM336, two patients with relapsed/refractory autoimmune hemolytic anemia showed rapid and sustained remissions out to month six, without other immunosuppressive therapies

Ouro Medicines plans to begin a clinical trial of OM336 in rare autoimmune cytopenias, including relapsed/refractory autoimmune hemolytic anemia and immune thrombocytopenic purpura

Trial initiation is expected in the second half of 2025

SAN FRANCISCO, June 12, 2025 /PRNewswire/ -- Ouro Medicines, a biotechnology company developing immune reset therapeutics for people living with chronic, immune-mediated diseases, today announced plans to initiate a multi-national clinical trial of OM336, a BCMAxCD3 T cell engager antibody candidate, in patients with active autoimmune cytopenias, including relapsed/refractory autoimmune hemolytic anemia (AIHA) and immune thrombocytopenic purpura (ITP). The company expects to initiate the study in the second half of this year.

The company announced its plans to enter the clinic following publication of data from an investigator-sponsored study of OM336 in The New England Journal of Medicine (NEJM). In a Letter to the Editor, investigator Jun Shi, M.D., Ph.D. highlighted promising responses to OM336 in two patients with severe, potentially life-threatening, relapsed/refractory AIHA. The case reports published in NEJM are believed to be the first peer-reviewed data for a BCMA-directed T cell engager in the treatment of AIHA.

"We are excited to become a clinical stage company by advancing OM336 in autoimmune cytopenias, a set of indications where patients could face severe and life-threatening disease," said Jaideep Dudani, Ph.D., CEO, Ouro Medicines and Portfolio Principal, Monograph Capital. "Across investigator-sponsored studies in autoimmune cytopenias and in oncology studies sponsored by our partner, Keymed Biosciences, we have examined more than seventy patients' clinical experience with OM336. We believe the profile that has emerged suggests that OM336 may be able to achieve CAR T-like potency, with the dosing and administration of a monoclonal antibody, potentially unlocking a therapeutic cell depletion strategy in immune-mediated diseases including AIHA, ITP and beyond."

In the NEJM case reports, OM336 appeared to be generally well-tolerated, with a short course of subcutaneously-administered OM336 leading to rapid and deep B cell depletion in the circulation and in tissues, across early and late cell lineages. Both patients had AIHA that was relapsed/refractory to numerous treatments, such as glucocorticoids, splenectomy, anti-CD20 antibody, BTK inhibitor, and CD19-directed CAR T cell therapy. Hemoglobin and other laboratory parameters normalized within one month of starting OM336, and the patients remained in sustained remission off of all immunosuppressive therapies through the most recent evaluation, six months after study start. Durable hemoglobin response is the primary endpoint in recent and ongoing registrational studies in AIHA. No blood transfusions were administered, and there were no events of Cytokine Release Syndrome (CRS), Immune-Effector Cell-Associated Neurotoxicity Syndrome (ICANS), or infection. 

AIHA and ITP are among the most common types of autoimmune cytopenias, although both qualify as rare diseases in the U.S. Both AIHA and ITP can be severe and life-threatening, with symptoms that can significantly impact patients' quality of life.

"We're encouraged by OM336's emerging safety and efficacy profiles," said Neely Mozaffarian, M.D., Ph.D., CMO, Ouro Medicines. "The data from these case reports suggest that OM336 may have the potential to induce an 'immune reset,' mediated by the depletion of autoreactive B cells. As we advance our clinical program in autoimmune cytopenias, we anticipate learning more about the potential of OM336 as a new disease modifying therapy for these and other immune-mediated conditions."

Ouro will be presenting data on OM336 at the European Hematology Association (EHA) Annual Meeting on June 14 in a poster session. The presentation will highlight safety and efficacy data from a trial conducted by its partner Keymed Biosciences in relapsed/refractory multiple myeloma and its potential application for autoimmune cytopenias. The abstract for the session is available from the EHA here.

About OM336

OM336 is an investigational BCMAxCD3 bispecific antibody designed to potently induce T cell-dependent cellular cytotoxicity of BCMA-expressing target cells. With a detuned CD3-targeting arm, OM336 is designed to exhibit lower cytokine induction while still retaining potency, which may expand its therapeutic index. OM336 has a long half-life, which enables subcutaneous dosing and may contribute to safety and tolerability due to favorable PK parameters, as well as allow broader patient access through ease of administration.

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