Janssen Biotech and Pharmacyclics have received approval from the US Food and Drug Administration (FDA) for Imbruvica (ibrutinib) capsules as the first therapy indicated specifically for patients with Waldenström's macroglobulinemia (WM), a rare, indolent type of B-cell lymphoma.

The approval represents the fourth indication for the once-daily therapy Imbruvica, which received breakthrough therapy designation for this indication in February 2013.

Imbruvica inhibits a protein called Bruton's tyrosine kinase (BTK), which is a crucial signalling molecule in the B-cell receptor signaling complex, which plays an important role in the survival and spread of malignant B cells.

Janssen global oncology head Peter Lebowitz said: "The Imbruvica Waldenström's macroglobulinemia approval is a sterling example of collaboration for the benefit of patients."

"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 fact that the FDA granted full approval for this indication is meaningful and confirms the safety and efficacy of Imbruvica in WM."

The approval was based on data from a Dana-Farber Cancer Institute Phase II trial, which assessed the efficacy and tolerability of Imbruvica 420mg once-daily in 63 patients with previously treated WM.

According to the company, the response rate as assessed by an independent review committee using criteria adopted from the international workshop on WM was 62%.

Dana-Farber Cancer Institute Bing Center director for Waldenström's Macroglobulinemia Steven Treon said: "The approval was made possible because of the hard work and dedication of scientists and clinicians at various leading medical centres who diligently worked on the clinical trial that supports Imbruvica as a safe and effective therapy for patients with Waldenström's macroglobulinemia."