Rigel Announces R289 Granted Fast Track Designation by the FDA for Lower-Risk MDS

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SOUTH SAN FRANCISCO, Calif., Dec. 2, 2024 /PRNewswire/ -- Rigel Pharmaceuticals, Inc. (Nasdaq: RIGL), a commercial stage biotechnology company focused on hematologic disorders and cancer, today announced that the U.S. Food and Drug Administration (FDA) has granted Fast Track designation to R289 for the treatment of patients with previously-treated transfusion dependent lower-risk myelodysplastic syndrome (LR-MDS). R2891, Rigel's potent and selective dual inhibitor of IRAK1 and IRAK4, is being studied in an ongoing Phase 1b study evaluating the safety, tolerability, pharmacokinetics and preliminary activity in patients with LR-MDS who are relapsed or refractory to prior therapies.

"We are pleased that R289 has been granted Fast Track designation, which underscores the significant unmet need for patients with transfusion dependent lower-risk MDS," said Raul Rodriguez, Rigel's president and CEO. "By targeting inflammatory signaling, we believe that R289 has the potential to meaningfully improve the lives of those living with this disease."

"Lower-risk MDS affects a primarily elderly patient population that faces progressive cytopenias, particularly anemia, and treatment options for transfusion-dependent patients are limited," said Lisa Rojkjaer, M.D., Rigel's chief medical officer. "This designation is based on initial data from the ongoing Phase 1b study and highlights the potential of R289 to be a new therapeutic option for these patients. We look forward to working closely with the FDA to advance the clinical development of R289."

Fast track is a process designed to facilitate the development and expedite the review of drugs to treat serious conditions and fill an unmet medical need. A drug that receives Fast Track designation may benefit from more frequent interactions with the FDA over the course of drug development. In addition, the Fast Track program allows for eligibility for Accelerated Approval and Priority Review, if relevant criteria are met.

About R289
R289 is a prodrug of R835, an IRAK1/4 dual inhibitor, which has been shown in preclinical studies to block inflammatory cytokine production in response to toll-like receptor (TLR) and interleukin-1 receptor (IL-1R) family signaling. TLRs and IL-1Rs play a critical role in the innate immune response and dysregulation of these pathways can lead to various inflammatory conditions. Chronic stimulation of both these receptor systems is thought to cause the pro-inflammatory environment in the bone marrow responsible for persistent cytopenias in lower-risk MDS patients.2