Pharmacyclics has received approval from the US Food and Drug Administration (FDA) for its Imbruvica (ibrutinib) to treat patients with mantle cell lymphoma (MCL), a rare and aggressive type of blood cancer.
Imbruvica is being jointly developed and commercialised by Janssen Biotech and Pharmacyclics. It is approved for MCL patients who have received at least one prior therapy and is based on an overall response rate (ORR).
It works by blocking a specific protein called Bruton’s tyrosine kinase (BTK), a key signaling molecule of the B-cell receptor signalling complex that plays a major role in the survival of malignant B cells.
The safety and efficacy of Imbruvica were evaluated in an open-label, multi-centre, single-arm Phase II trial carried out in 111 patients with MCL who have received at least one prior therapy.
The ORR of 65.8% and duration of response (DOR) of 17.5 months observed in the Phase II study of PCYC-1104, and the serious and life-threatening nature of MCL, played a critical role in the FDA granting breakthrough therapy status to Imbruvica.
The company said that tumour response was evaluated according to the revised International Working Group (IWG) for non-Hodgkins lymphoma (NHL) criteria.
Imbruvica is one of the first medications to secure FDA approval via the breakthrough therapy designation pathway and it comes just over four months after the new drug application (NDA) submission was completed in late-June.
Pharmacyclics CEO and chairman of the board Bob Duggan said after observing early signs of efficacy and tolerability of Imbruvica four years ago, the company single-mindedly focused its attention on fully developing this medicine.
"Presently we are in the midst of investigating this medicine in numerous additional B-cell malignancies with 37 clinical studies ongoing," Duggan said.
The most common side effects reported in patients receiving Imbruvica include low levels of platelets in the blood, diarrhea, anemia, fatigue, musculoskeletal pain, swelling, upper respiratory infection, nausea, bruising, shortness of breath, constipation, rash, abdominal pain, vomiting and decreased appetite.
According to the company, other clinically significant side effects in patients are bleeding, infections, kidney problems and the development of other types of cancers.
Imbruvica is the third drug approved to treat MCL in addition to the approval of Velcade in 2006 and Revlimid in 2013 to treat the disease.
Image: Low magnification micrograph of mantle cell lymphoma of the terminal ileum. Photo: courtesy of Nephron.