Mocetinostat Receives ‘Orphan Drug’ Designation for Treatment of Myelodysplastic Syndrome
Mid-stage trials are under way
Mocetinostat (Mirati Therapeutics, Inc), an orally bioavailable, spectrum-selective histone deacetylase (HDAC) inhibitor, has been granted an “orphan drug” designation by the FDA as a treatment for myelodysplastic syndrome (MDS).
The drug is being developed in phase II clinical studies in combination with azacitidine (Vidaza, Celgene Corp.) as a treatment for intermediate- and high-risk MDS, and as a single-agent treatment in patients with diffuse large B-cell lymphoma (DLBCL) and bladder cancer, targeting specific genetic mutations in histone acetylation that increase the likelihood of a response in tumor cells.
The FDA’s Office of Orphan Drug Products grants an “orphan drug” designation to support the development of medications for underserved patient populations or for rare disorders that affect fewer than 200,000 people in the U.S.
In 2013, data presented at the American Society of Hematology (ASH) annual meeting demonstrated promising clinical response rates in patients with MDS treated with mocetinostat in combination with azacitidine.
In this open-label, phase I/II trial, researchers evaluated 66 patients with MDS or acute myeloid leukemia. A subset of 22 patients had intermediate- and high-risk disease and baseline bone marrow blasts of 5% to 20% at screening, representing a population of patients with refractory anemia with excess blasts (RAEB-1 or RAEB-2) — a type of MDS that is associated with poor clinical outcomes. Of these 22 patients, 59% experienced an objective response to treatment with mocetinostat plus azacitidine. The median overall survival was 12.4 months.