Experimental Blood Cancer Rx is Showing Positive Results

Mantle cell lymphoma responds to ibrutinib

(RxWiki News) There is excellent news for people with mantle cell lymphoma, a rare blood cancer. An experimental drug is demonstrating impressive results in a phase II clinical trial. But this is a limited research study, and the product is not yet available.

Researchers report that ibrutinib has “unprecedented” impact on mantle cell lymphoma that has either stopped responding to other therapies or has returned.

"Ask about cancer drugs in clinical trials."

"I believe we are witnessing a breakthrough in mantle cell lymphoma. This is great news for patients," said lead study author, Michael Wang, MD, associate professor at The University of Texas MD Anderson Cancer Center Departments of Lymphoma and Myeloma and Stem Cell Transplantation and Cellular Therapy.

Mantle cell lymphoma (MCL) is diagnosed in about 5,000 Americans every year. It’s a form of non-Hodgkin's lymphoma, which is a cancer of the lymph system that about 70,000 people in this country are diagnosed with every year. MCL tends to return after initial therapy, which can be very toxic.

Dr. Wang explains why there’s excitement surrounding this experimental drug, "In a heavily treated relapsed [returned] or refractory [resistant] population, oral ibrutinib induced a response rate as high as 70 percent - better than any other single agent ever tested in MCL," he said. "The response is durable with a long progression-free survival."

The drug works by going after a molecule - Bruton's tyrosine kinase (BTK) – that’s in the driver’s seat with CML. Results of the ongoing trial were presented at the 54th American Society of Hematology Annual Meeting and Exposition.

To date, 115 people have enrolled in the study, and the drug’s effectiveness has been tested in 110 individuals. The median age of these folks was 68, and 77 percent had stage 4 disease. Researchers found that 75 percent of the patients responded to the drug, with 39 percent achieving complete remissions.

The longer people were taking the medication, the more improvement they saw.

The drug was also gentle on normal cells. There were few serious side effects, which typically included diarrhea, fatigue, upper respiratory tract infections, nausea and rash.

"What impressed me the most is the high complete remission rate, which continues to improve with time, and yet it is the safest drug we have for mantle cell lymphoma," Wang said in a statement. "Previously such a rate could be achieved only with combination cyto-reductive chemotherapy, which is bone marrow suppressive and toxic."

Ibrutinib was developed by Pharmacyclics, Inc., which funded this study. Before publication in a peer-reviewed journal, all research is considered preliminary.

Review Date: 
December 21, 2012