John Mascarenhas, MD, Icahn School of Medicine at Mount Sinai, New York, NY, discusses the Phase II study (NCT02426086) of imetelstat, a telomerase inhibitor, in advanced myelofibrosis (MF) patients who have failed ruxolitinib therapy. While the spleen responses were modest, the high dose arm of the study experienced an impressive median survival of 29-30 months and lower telomerase activity levels. As a result, imetelstat is now moving into a Phase III study where it will be tried against best available therapies in an attempt to improve overall survival. The study will also look into biomarkers associated with response, including shorter telomere length. This interview took place during the 62nd American Society of Hematology (ASH) Annual Meeting and Exposition, 2020.