The US Food and Drug Administration has expanded approval of Johnson & Johnson/Pharmacyclic’s Imbruvica for patients with Waldenström’s macroglobulinemia, a rare indolent type of B-cell lymphoma.

The approval, the first by the FDA specifically for WM, represents the fourth indication for Imbruvia (ibrutinib) since its initial green light in November 2013 for mantle cell lymphoma patients who received one prior therapy. Last February, it was granted accelerated approval for use in patients with previously treated chronic lymphocytic leukaemia and then in July 2014 for CLL patients who carry a deletion in chromosome 17.

The approval is based on a 63-patient study which showed that 62% of participants had their cancer shrink after treatment. At the time of the study, the duration of response ranged from 2.8 months to 18.8 months.

A type of non-Hodgkin lymphoma, WM usually gets worse slowly over time and causes abnormal blood cells to grow within the bone marrow, lymph nodes, liver and spleen. In WM, abnormal B-cells also overproduce a protein known as immunoglobulin M or IgM (macroglobulin) that may lead to excess bleeding and problems with vision and the nervous system.

The Imbruvica WM approval “is a sterling example of collaboration for the benefit of patients”, said Peter Lebowitz, oncology head at J&J’s Janssen unit. He added that “all partners involved recognised the urgent need for approved treatment options for those living with WM, and collectively set an aggressive pace to gain approval”.

The thumbs-up comes more than two months ahead of its action date of April 17.