Rytelo Gains FDA Approval to Treat Low-Risk Myelodysplastic Syndromes

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Geron announced yesterday an FDA approval for Rytelo (imetelstat) to treat adult patients with low-to intermediate-risk myelodysplastic syndromes (MDS) with transfusion-dependent anemia. It is to be administered intravenously over two hours every four weeks. Details were discussed during a conference call with Geron management held today at 8 a.m. ET.

Imetelstat is a telomerase inhibitor. Telomerase is a naturally occurring enzyme that keeps cells alive by adding DNA to the ends of telomeres, which are at the end of chromosomes. Uncontrolled telomerase expression has been found in nearly 90% of biopsies from human cancers, according to Geron.

Myelodysplastic syndromes are a group of cancers in which immature blood cells in the bone marrow do not develop. This can lead to anemia, frequent infections or leukemia. The median age of diagnosis is 70 years of age. Patients often become blood transfusion dependent, which impacts quality of life and shortens survival.

Rytelo is approved for patients requiring four or more transfusions over eight weeks or who are ineligible for or have lost response to erythropoiesis-stimulating agents, which stimulate the bone marrow to make more red blood cells. Currently, 1 in 10 LR-MDS patients are ESA-ineligible, according to the conference call. It will be available in two sizes. The first size, an 188mg vial will be available by the end of June 2024 and have a wholesale price of $9,884. The second size, a 47 mg vial, is expected by the end of this summer with a wholesale price of $2,471.

This FDA approval is based on the results of an IMerge phase 3 clinical trial, published in The Lancet.

“For patients with lower-risk MDS and anemia who are transfusion dependent, we have very few options today and often cycle through available therapies, making the approval of Rytelo potentially practice changing for us,” Rami Komrokji, M.D., vice chair, Malignant Hematology Department, Moffitt Cancer Center and investigator in the IMerge clinical trial, said in a press release. “The treatment goal for patients with LR-MDS and anemia is transfusion-independence and before today, this wasn’t possible for many patients.”

Clinically meaningful efficacy results were seen across MSD subgroups. The most common adverse reactions neutropenia (72%), where there are low levels of a white blood cell type called neutrophils and thrombocytopenia (65%) a condition that occurs when the platelet count in the blood is too low. These reactions lasted a median duration of less than two weeks.