In February 2013, FDA granted Breakthrough Therapy Designations for ibrutinib as a monotherapy for the treatment of patients with relapsed or refractory mantle cell lymphoma and as a monotherapy for the treatment of patients with Waldenström’s macroglobulinemia, both of which are also B-cell malignancies.

In April 2013, the FDA granted a third Breakthrough Therapy Designation for the investigational oral agent ibrutinib as monotherapy for the treatment of chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma patients with deletion of the short arm of chromosome 17 (deletion 17p). Patients harboring a deletion within chromosome 17 generally have poor response to chemoimmunotherapy and have limited treatment options. The presence of deletion 17p is one of the worst prognostic factors in patients with CLL.

The Breakthrough Therapy Designation is intended to expedite the development and review of a potential new drug for serious or life-threatening diseases where “preliminary clinical evidence indicates that the drug may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development.” The designation of a drug as a Breakthrough Therapy was enacted as part of the 2012 FDA Safety and Innovation Act. ■