The US Food and Drug Administration (FDA) has approved Janssen Biotech's Imbruvica (ibrutinib) capsules as the first therapy indicated specifically for patients with  Waldenström's macroglobulinemia (WM), a rare, indolent type of B-cell lymphoma. This represents the fourth indication for Imbruvica since its initial approval in November 2013. Imbruvica was granted Breakthrough Therapy Designation for WM by the FDA and is being jointly developed and commercialised by Janssen and Pharmacyclics, Inc.

The update to the Imbruvica label is based on data from a Dana-Farber Cancer Institute phase 2 study. Earlier releases of these data were previously presented at the 2013 American Society of Hematology (ASH) and the 2013 International Congress of Malignant Lymphoma (ICML) annual meetings.

"Since the first description of Waldenström's macroglobulinemia more than 70 years ago, there has been no approved treatment for this cancer. Rather, doctors relied on therapies borrowed from similar cancers to treat these patients. I am truly grateful to the FDA for their thorough review and expedited approval of Imbruvica for this indication. The approval was made possible because of the hard work and dedication of scientists and clinicians at various leading medical centers who diligently worked on the clinical trial that supports Imbruvica as a safe and effective therapy for patients with Waldenström's macroglobulinemia," says Steven P. Treon, MD, Director of the Bing Center for Waldenström's Macroglobulinemia at the Dana-Farber Cancer Institute and Associate Professor at Harvard Medical School, and, who led the trial.

"Waldenström's macroglobulinemia patients and physicians have been waiting for a treatment specifically studied and approved to treat this rare disease," says Carl Harrington, president of the International Waldenstrom's Macroglobulinemia Foundation. "The approval of Imbruvica is an important milestone for the entire global WM community and has the potential to positively impact our patients, their physicians and caregivers."

The phase 2 multi-centre study on which this approval was based evaluated the efficacy and tolerability of Imbruvica 420 mg once daily in 63 patients with previously treated WM (median age of 63; range, 44-86 years old). The response rate as assessed by an Independent Review Committee using criteria adopted from the International Workshop on WM was 62 per cent (95 per cent CI, 48.8, 73.9). Nearly 51 per cent of patients achieved a partial response (PR) and 11 percent achieved a very good PR. No complete responses were reported. The median duration of response has not been reached (2.8+, 18.8+ months). The median time to response was 1.2 months (range, 0.7-13.4 months).

The most commonly occurring adverse reactions in the WM trial (=20 percent of Imbruvica patients) were neutropenia (decreased amount of neutrophils in the blood), thrombocytopenia (decrease in platelets in the blood), diarrhoea, rash, nausea, muscle spasms and fatigue. Six per cent of patients in the WM trial receiving Imbruvica discontinued treatment due to adverse events. Adverse events leading to dose reduction occurred in 11 per cent of patients.

"The Imbruvica Waldenström's macroglobulinemia approval is a sterling example of collaboration for the benefit of patients," said Peter F. Lebowitz, MD, Global Oncology Head, Janssen. "All partners involved recognized 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."

In the US, there are approximately 1,000 to 1,500 new cases of WM each year and the median age at diagnosis is 60 to 70 years of age.2,3 WM (a clinically recognised subset of lymphoplasmacytic lymphoma, or LPL) begins with a malignant change to the B cell, a type of white blood cell (lymphocyte), during its maturation so that it continues to reproduce more malignant B cells. WM cells make large amounts of a certain type of antibody (immunoglobulin M, or IgM) mostly in the bone marrow. Antibodies such as IgM normally help the body to fight infection. However, the overproduction of IgM, a hallmark of WM, often leads to the bone marrow becoming dysfunctional. Typically, patients with WM are diagnosed after developing symptoms associated with the disease such as anaemia, fatigue and night sweats.

Imbruvica was one of the first therapies to receive US approval after having received the FDA's Breakthrough Therapy Designation. Imbruvica works by blocking a specific protein called Bruton's tyrosine kinase (BTK). The BTK protein transmits important signals that tell B cells to mature and produce antibodies and is needed by specific cancer cells to multiply and spread. Imbruvica targets and blocks BTK, inhibiting cancer cell survival and spread.

Janssen and Pharmacyclics are striving to make the process of obtaining Imbruvica and navigating insurance benefits easy for patients. The YOU&i Support Program is a personalised programme that includes information on access and affordability, nurse call support and resources for patients being treated with Imbruvica. This includes the YOU&i Instant Savings program, which provides co-pay support and benefits information to eligible commercially-insured patients. This program is not valid for patients with Medicare or Medicaid.