FDA fast-tracks potential new option for autoimmune blood diseases
Gamgertamig earns designation for AIHA and ITP
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The U.S. Food and Drug Administration (FDA) has granted fast-track designation to Ouro Medicines’ experimental treatment gamgertamig for autoimmune hemolytic anemia (AIHA), a group of autoimmune diseases that includes cold agglutinin disease.
Fast-track designation is intended to accelerate the development and review of potential treatments for serious diseases with unmet medical needs. It allows for more frequent communication with the FDA and may open faster approval pathways, such as priority review or accelerated approval, if clinical trial results are positive.
At the same time, the agency also granted fast-track designation to gamgertamig for immune thrombocytopenia (ITP), another autoimmune disease that affects blood components.
“Fast track designation for gamgertamig in both AIHA and ITP underscores the need for new treatment options in these potentially life-threatening conditions,” Neely Mozaffarian, MD, PhD, chief medical officer of Ouro, said in a company press release.
FDA previously granted orphan drug status to gamgertamig
The FDA had previously granted orphan drug designation to gamgertamig for the treatment of AIHA and ITP. Orphan drug designation is given to therapies developed for rare diseases and provides benefits such as additional guidance from the FDA during development and, if approved, a period of market exclusivity for the specific indication.
“We are highly encouraged by the data generated to date in Ouro-sponsored and investigator-initiated studies of gamgertamig in several indications,” Mozaffarian said.
An Ouro-sponsored Phase 1b clinical trial (NCT07083960) is testing gamgertamig in up to 32 adults with active AIHA (including CAD), active ITP, or both, who have not responded to at least one prior treatment or whose disease has returned.
Early dosing has been completed in the first group of participants, and enrollment in additional groups is ongoing at clinical sites in the U.S. and Australia.
AIHA and ITP are autoimmune diseases affecting blood cells
Both AIHA and ITP are autoimmune cytopenias — conditions in which the immune system produces antibodies that mistakenly attack the body’s own blood cells, leading to their early destruction.
ITP affects platelets, which play a key role in blood clotting, while AIHA affects red blood cells. CAD is a rare form of AIHA in which self-reactive antibodies target red blood cells at colder temperatures, leading to their destruction and symptoms such as fatigue.
Gamgertamig, also called OM336, is a bispecific antibody, meaning it can bind to two targets at the same time, and is designed to harness the body’s immune system to eliminate B-cells, the immune cells responsible for producing antibodies.
The therapy works by binding to CD3, a protein found on immune T-cells, and BCMA, a receptor commonly found on antibody-producing B-cells. By linking these cells together, gamgertamig is expected to trigger B-cell destruction and reduce levels of harmful, self-reactive antibodies.
Gamgertamig is also engineered to limit an excessive immune activation, which could help provide longer-lasting benefit while avoiding the risks associated with broad immune suppression.
Phase 1b trial is testing gamgertamig in AIHA and ITP
The ongoing Phase 1b trial is evaluating the safety and tolerability of gamgertamig over 12 weeks when given as a subcutaneous, or under-the-skin, injection. The study is also examining how the drug moves through the body (pharmacokinetics) and whether it triggers immune responses against the therapy itself.
Ouro is also conducting a separate Phase 1 trial (NCT07229144) evaluating gamgertamig in adults with one of two other autoimmune diseases — Sjögren’s disease and idiopathic inflammatory myopathies — whose disease has returned or not responded to prior treatment.
“Our ongoing clinical trial of gamgertamig in autoimmune cytopenias, including AIHA and ITP, combined with our study in Sjögren’s disease and idiopathic inflammatory myopathies, will continue to generate meaningful data in these indications, offering the potential of an immune reset approach which could redefine the standard of care for these immune-mediated conditions,” Mozaffarian said.
