Imetelstat was evaluated in lower-risk transfusion-dependent myelodysplastic patients that were refractory to prior ESA therapy and showed activity in terms of anemia responses. It was also tested in high-risk myelofibrosis patients who were refractory or relapsed after JAK inhibitor therapy and showed benefit in symptom, spleen, reduction in bone marrow fibrosis, reduction driver mutation allele burden and a signal for improved survival...
Imetelstat was evaluated in lower-risk transfusion-dependent myelodysplastic patients that were refractory to prior ESA therapy and showed activity in terms of anemia responses. It was also tested in high-risk myelofibrosis patients who were refractory or relapsed after JAK inhibitor therapy and showed benefit in symptom, spleen, reduction in bone marrow fibrosis, reduction driver mutation allele burden and a signal for improved survival.
In this analysis, we took a deeper dive into the safety and tolerability of imetelstat across both studies. This is an infusional drug that was given at 9.4 milligrams per kilogram every three weeks in the MF population, and 7.5 milligram per kilogram every four weeks in the MDS population.
The frequency of grade III/IV cytopenias range from approximately 30 to 60%. This is neutropenia and thrombocytopenia across both studies, but were reversible and rarely led to treatment discontinuation, probably less than 5% of patients for this reason. The median time to onset were in the first two cycles of therapy and liver toxicity was not a big issue that was seen in this trial. There was no signal for liver insult or liver injury. Otherwise, the drug was well-tolerated and proves the point that this drug can be delivered within the three-to-four-week period where counts can regain and subsequent cycles can be given.