Dr. Tefferi on the Toxicity Profile of Imetelstat

Ayalew Tefferi, MD, hematologist, Mayo Clinic, Rochester, Minnesota, discusses the toxicity of imetelstat in patients with myelofibrosis.

Tefferi says there were few instances of non-hematologic toxicities when patients were given the drug every three weeks. Although clinicians were excited that there were no grade 3 or 4 toxicities, the drug has the ability to cause myelosuppression.

When patients were given imetelstat every three weeks, the incidence of grade 4 thrombocytopenia or neutropenia was below 10%, Tefferi says. However, when the drug was used every week, the incidence of grade 4 adverse events increased. Tefferi says that out of 11 patients who received weekly imetelstat, two of them developed severe myelosuppresion. Consequently, the weekly regimen was abandoned.