The Food and Drug Administration (FDA) has granted a fast track designation to the investigational compound R289 for the treatment of patients with previously treated transfusion-dependent lower-risk myelodysplastic syndrome (LR-MDS).
According to a news release from biotechnology company Rigel Pharmaceuticals, R289 is a selective dual inhibitor of the enzymes IRAK1 and IRAK4 currently being evaluated in a phase 1B study of the safety, tolerability, pharmacokinetics and preliminary activity of the drug among 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," Raul Rodriguez, the president and CEO of Rigel, said in a news release. "By targeting inflammatory signaling, we believe that R289 has the potential to meaningfully improve the lives of those living with this disease."
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"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 Dr. Lisa Rojkjaer, chief medical officer of Rigel, in the release. "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."
Inhibiting the IRAK1 and IRAK4 enzymes is a potential target for treating LR-MDS by decreasing inflammation and cell death in a patient’s bone marrow, allowing for the restoration of hematopoiesis, or healthy blood cell production, according to material on the phase 1b clinical trial presented at the American Society of Clinical Oncology meeting in 2023 and published in the Journal of Clinical Oncology.
With 34 participating patients, the trial launched in 2022 and is expected to be completed in 2025, according to the trial’s listing on clinicaltrials.gov.
Researchers stated in the Journal of Clinical Oncology that the safety and pharmacokinetics of the treatment had previously been established in a phase 1 study of healthy volunteers, noting that R289 was well-tolerated with no serious or severe side effects being reported.
In the announcement, Rigel Pharmaceuticals stated that initial data from the study’s dose escalation phase with a data cutoff date of July 15, 2024, shows that among 14 patients who were evaluated for efficacy, red blood cell transfusion independence occurred in 36% of patients receiving R289 at doses of up to 500 milligrams daily with a median duration of transfusion independence of 29 weeks.
Most side effects, researchers stated, were mild and transient, with the most common mild and moderate side effects being headaches and gastrointestinal disturbances.
Rigel announced in November that findings from the study will be shared at the 66th American Society of Hematology Annual Meeting and Exposition, held from Dec. 7 to 10.
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