An application for priority review of a combination therapy with AbbVie Inc.'s Imbruvica and Roche Holding AG's Gazyva to treat two types of blood cancer has been accepted by the U.S. Food and Drug Administration.

The priority review status will expedite the process for regulatory approval of the combination of Gazyva and Imbruvica, also known as obinutuzumab and ibrutinib, respectively. Approval would mark the first FDA nod for a chemotherapy-free, protein-attacking drug combination for initial treatment of chronic lymphocytic leukemia.

The combination is being studied to treat chronic lymphocytic leukemia or small lymphocytic lymphoma. Chronic lymphocytic leukemia is a slow-progressing blood cancer that affects certain white blood cells in bone marrow and blood. The disease impacts around 115,000 patients in the U.S., with almost 20,000 new cases diagnosed every year. Small lymphocytic lymphoma is a slow-growing lymphoma biologically similar to chronic lymphocytic leukemia in which too many immature white blood cells cause lymph nodes to become larger than normal.

The FDA acceptance is based on results of a phase 3 study called Illuminate. An independent review committee determined that the Imbruvica combination was better than combining Gazyva with chemotherapy drug chlorambucil in increasing the length of time that a patient with previously untreated leukemia and lymphoma lived without the disease worsening.

Imbruvica has been granted four breakthrough therapy designations from the FDA, and is approved to treat Waldenström's macroglobulinemia, previously treated marginal zone lymphoma, and chronic graft-versus-host disease. Additionally, the U.K.'s National Institute for Health and Care Excellence has approved Imbruvica for previously treated mantle cell lymphoma.