Johnson & Johnson (JNJ) and Pharmacyclics Inc. (PCYC)’s experimental medicine ibrutinib helps keep a hard-to- treat form of the most common type of leukemia at bay for at least a year, U.S. researchers said.
The study from the second of three phases needed to win U.S. approval found one pill a day cut the amount of disease in half in the lymph nodes for 95 percent of patients. All patients saw their enlarged spleens shrink, while tumor cells in the bone marrow fell 82 percent, according to the study presented at the American Association for Cancer Research meeting in Washington.
The findings suggest ibrutinib may already be the best treatment for patients with a genetic defect that limits their response to chemotherapy, said Adrian Wiestner, head of the Lymphoid Malignancies Section at the National Heart, Lung, and Blood Institute’s hematology branch. The drug today was named a breakthrough therapy by U.S. regulators for the treatment of chronic lymphocytic leukemia in patients with the defect, known as a deletion of chromosome 17p.
“The degree of tumor reduction achieved by one pill a day is nothing short of surprising,” Wiestner said in a statement. “The drug is effective against the disease in lymph nodes, spleen and bone marrow. This is important because existing therapies often fail to effectively eliminate cancer cells at these tissue sites.”
The study included 53 patients with chronic lymphocytic leukemia, or CLL, who either had the genetic defect or were older than 65, a group that typically can’t withstand the aggressive treatment needed to control the disease. Researchers found some patients had a 90 percent reduction in the amount of disease in their lymph nodes after just two months of treatment.
One patient had progressive disease, and two patient deaths were deemed unrelated to their drug treatment. The most common side effects were diarrhea, fatigue and rash, occurring in fewer than 13 percent of patients.
The study was funded by the National Institutes of Health’s intramural research program.
CLL develops in about 16,000 people in the U.S. each year, according to the American Cancer Society, making it the most common type of leukemia. Ibrutinib works by inhibiting Bruton’s tyrosine kinase, part of the pathway that helps the cancer take hold and spread. The drug’s ability to blunt the activity and proliferation of CLL was remarkable, Wiestner said.
The drug from Sunnyvale, California-based Pharmacyclics and New Brunswick, New Jersey-based J&J is being studied alone and in combination with other treatments for a range of blood cancers. The therapy received breakthrough status in February for two types of lymphomas.
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