Chronic Lymphocytic Leukemia, B Gone

Chronic lymphocytic leukemia remissions high when treated with b cell receptor inhibitors

(RxWiki News) Typical cancer treatments involve broad spectrum drugs that can cause harmful effects to a wide range of cells. Until recently, specialized medicines without a long list of side effects were a rarity.

Clinical trials have shown that a new class of drugs for chronic lymphocytic leukemia (CLL) has achieved excellent rates in remission with minimal side effects.

The drugs, called B Cell Receptor Inhibitors, specifically target the B cells replicating out of control in leukemia.

"Ask your oncologist about B Cell Receptor Inhibitor clinical trials."

In a presentation to the American Society of Hematology in December, Susan O'Brien, M.D. outlined the newest results from phase II of the clinical trial on PCI-32765, B Cell Receptor Inhibitor. Dr. O'Brien is a professor in the Department of Leukemia at MD Anderson.

This phase of the clinical trial looked at the effectiveness of the drug in 61 patients with chronic lymphocytic leukemia. 

"When we first reported results of this trial at ASH [American Society of Hematology] a year ago, 25 percent or patients had a partial response," Dr. O'Brien says.

"By the time we presented in June at the American Society of Clinical Oncology meeting, the overall response rate was 48 percent. Now it's approaching 70 percent with either complete or partial remission."

Normally leukemias are fought with broad spectrum drugs that kill a wide range of immune cells, including B cells. On the other hand, the new drug "PCI-32765 is not myelosuppressive.

The main side effect is mild diarrhea that is usually self-limiting," Dr. O'Brien said.

Diarrhea and nausea were the number one side effect, occurring in one third of patients. Two patients quit the study due to side effects, six patients switched to a lower dose. 

Phase III is scheduled to start soon, where the drug will be compared side by side to the current best drug in a larger group of patients. 

Pharmacyclics Inc., the drug's developer, is funding the clinical trial.

Review Date: 
January 21, 2012