Pharmacyclics Blood-Cancer Drug Controls Disease in Study

Pharmacyclics Inc. (PCYC)’s experimental treatment for chronic lymphocytic leukemia, a blood cancer that affects adults 50 and older, slowed progression of the disease when used alone and with another drug, studies showed.

In a study of 116 patients, the medicine, called ibrutinib, helped control the malignancy in 68 percent who hadn’t been previously treated for the blood cancer and in 71 percent of those who had relapsed or were at risk for relapse, Sunnyvale, California-based Pharmacyclics said today in a statement.

Ibrutinib is from a new class of medicines for chronic lymphocytic leukemia, or CLL, a cancer that strikes about 16,000 Americans a year at a median age of about 72. The goal is to use the drug without chemotherapy, a standard treatment that can be too toxic for some elderly patients. The drug may generate as much as $5 billion a year if approved for CLL and other blood cancers, said Michael Yee, an RBC Capital Markets analyst.

“We are very encouraged that these results with ibrutinib continue to support the possibility that we can address some of the critical unmet needs,” John Byrd, leukemia research professor at Ohio State University Medical Center and lead study author, said in the statement.

Results also showed that 96 percent of patients in the previously untreated group, and 75 percent of those at high risk, lived 26 months without the disease worsening. The most common side effects were diarrhea, fatigue, nausea and rash. The findings showed no evidence of cumulative toxicity or long-term safety concerns, according to the statement.

Blood Malignancy

CLL originates from white blood cells in bone marrow and can spread to the liver, lymph nodes and spleen, according to the American Cancer Society. The disease may spread for years without any symptoms, and many patients aren’t treated.

In a second study of 40 patients, ibrutinib worked in combination with Roche Holding AG’s (ROG) Rituxan. The drug helped control the cancer in 83 percent. Thirty-eight of the 40 patients continued on the therapy without their disease worsening at a follow-up of three to six months. Results from the studies will be formerly presented tomorrow at the American Society of Hematology meeting in Atlanta.

Ibrutinib is designed to go after an enzyme within the so- called Bruton’s tyrosine kinase pathway that enables abnormal white blood cells to proliferate. It is currently being tested in last of three phases of trials typically required for U.S. approval. Pharmacyclics is developing the drug with New Brunswick, New Jersey-based Johnson & Johnson (JNJ), the world’s biggest health-care products company.

Slow-Growing

Because one form of CLL is slow growing, doctors typically don’t treat these patients, Pharmacyclics said in the statement. Others who have a more aggressive form are given a three-drug combination of fludarabine, cyclophosphamide and Rituxan.

This can be toxic for elderly patients, attacking cancerous and healthy cells, Jan Burger, an associate professor at The University of Texas MD Anderson Cancer Center in Houston, said in an interview.

“We always hoped we’d find something that’s more targeted that damages the leukemia cells but not the patient,” Burger, a consultant to Pharmacyclics who authored one of the company’s studies presented at the meeting. “And ibrutinib is one of these very promising new drugs.”

Pharmacyclics shares gained $1.01, or 1.8 percent, to close at $56.02 yesterday in New York. The share have more than tripled this year on the drug’s prospects.

To contact the reporter on this story: Ryan Flinn in San Francisco at rflinn@bloomberg.net

To contact the editor responsible for this story: Reg Gale at rgale5@bloomberg.net