Rigel's R289 Receives FDA Orphan Drug Status for MDS

SOUTH SAN FRANCISCO, Calif., Jan. 9, 2025 – Rigel Pharmaceuticals, Inc., a biotechnology company specializing in treatments for hematologic disorders and cancer, has announced a significant regulatory milestone. The U.S. Food and Drug Administration (FDA) has granted Orphan Drug designation to R289, a therapeutic candidate for treating myelodysplastic syndromes (MDS). This designation provides Rigel with specific development incentives for R289, which is currently under investigation in a Phase 1b clinical trial.

R289 is a dual inhibitor of IRAK1 and IRAK4, a mechanism which is being evaluated for its safety, tolerability, pharmacokinetics, and preliminary efficacy in patients with lower-risk myelodysplastic syndromes who have not responded to previous treatments. Rigel's president and CEO, Raul Rodriguez, highlighted the importance of this designation by stating that it underscores the urgent need for innovative treatments for MDS patients. The FDA's Orphan Drug designation is intended to encourage the development of drugs for rare diseases affecting fewer than 200,000 individuals in the U.S. Benefits of this designation can include tax credits, exemption from certain FDA fees, and seven years of market exclusivity once the drug is approved.

Prior to this, R289 also received Fast Track designation from the FDA, which is aimed at expediting the review process for drugs that treat serious conditions and fill an unmet medical need, specifically for patients with previously treated transfusion-dependent lower-risk MDS.

R289 works at a molecular level by being a prodrug of R835, which inhibits IRAK1/4. In preclinical studies, this compound has shown potential in blocking the production of inflammatory cytokines, which are triggered by toll-like receptor (TLR) and interleukin-1 receptor (IL-1R) signaling. These receptors are crucial in the body's immune response, and when their pathways are dysregulated, it can lead to chronic inflammatory conditions. In lower-risk MDS patients, such chronic inflammation in the bone marrow is believed to cause persistent cytopenias.

Rigel Pharmaceuticals, based in South San Francisco, California, was founded in 1996 with a mission to discover and develop novel therapies that significantly enhance the lives of patients battling hematologic disorders and cancer. The company remains committed to advancing its pipeline, which includes R289, in the hopes of providing new treatment options for patients in need.

It's important to note that R289 is still under investigation and has not yet received FDA approval. Rigel continues to focus on its clinical developments, supported by data from ongoing studies, to bring promising therapies like R289 to market. As the company forges ahead, it remains dedicated to addressing the challenging medical needs within the realm of hematologic disorders and cancer.