Phase II/III Pooled Data Analysis: Imetelstat Benefit in MDS Independent of Prior Therapy

A pooled data analysis of the IMerge phase II/III trial has evaluated whether prior therapies affect the efficacy of imetelstat treatment in patients with red blood cell transfusion-dependent lower-risk myelodysplastic syndromes (MDS). It was presented at the 66^th American Society of Hematology Annual Meeting & Exposition in San Diego, California.

According to lead author Uwe Platzbecker, MD, of Leipzig University Hospital in Germany, the analysis found “[p]atients who were [erythropoiesis-stimulating agent (ESA)]-ineligible or who had prior treatment with luspatercept, lenalidomide, or [a hypomethylating agent (HMA)] in IMerge experienced clinical benefit from imetelstat treatment.”

The analysis cohort comprised 226 patients who received imetelstat intravenously every four weeks at 7.1 mg/kg. In the cohort, 204 patients had previously received an ESA and 22 were ineligible for this therapy. Thirty-five patients had received prior luspatercept, 26 lenalidomide, and 22 an HMA. Enrolled participants may have received more than one prior therapy.

The analyst team calculated that among patients with prior ESA therapy, 40% achieved red blood cell transfusion independence which lasted eight weeks or longer and 28% independence of 24 weeks or longer. 43% of the patients achieved hematologic improvement-erythroid, and 33% had a hemoglobin rise of 1.5 g/dL or greater with a duration of at least eight weeks.

Among the patients who were ineligible for prior ESAs, 36% achieved transfusion independence of eight weeks or longer and 14% of 24 weeks or longer. 41% of these patients achieved hematologic improvement-erythroid, and 2% had hemoglobin increase of 1.5 g/dL or greater with a duration of at least eight weeks.

In the group of patients who had prior luspatercept therapy, 29% achieved transfusion independence of eight weeks or longer and 20% of 24 weeks or longer. 26% of the patients achieved hematologic improvement-erythroid, and 29% had a hemoglobin increase of 1.5 g/dL or greater with a duration of at least eight weeks.

For patients with prior lenalidomide therapy, 23% achieved transfusion independence of eight weeks or longer and 12% of 24 weeks or longer. 31% of the patients achieved hematologic improvement-erythroid, and 19% had a hemoglobin increase of 1.5 g/dL or greater with a duration of at least eight weeks.

Among patients who received prior HMA therapy, 14% achieved transfusion independence of eight weeks or longer and 9% of 24 weeks or longer. 18% of the patients achieved hematologic improvement-erythroid, and 14% had a hemoglobin increase of 1.5 g/dL or greater with a duration of at least eight weeks.

Dr. Platzbecker wrote that although the cohort size was small, its findings “have important clinical implications, suggesting that imetelstat demonstrates clinical activity regardless of prior therapies.”

Reference

Platzbecker U, Santini V, Zeidan AM, et al. Effect of prior treatments on the clinical activity of imetelstat in transfusion-dependent patients with erythropoiesis-stimulating agent, relapsed or refractory/ineligible lower-risk myelodysplastic syndromes. Abstract #352. Presented at the 66th American Society of Hematology Annual Meeting and Exposition; December 7-10, 2024; San Diego, California.