SUNNYVALE, Calif., April 8, 2013 /PRNewswire/ -- Pharmacyclics, Inc. (Nasdaq: PCYC) today announced results from a Phase II trial of the investigational oral agent ibrutinib which demonstrated rapid and sustained disease control as a monotherapy in untreated, relapsed and refractory chronic lymphocytic leukemia (CLL) patients, irrespective of characteristics that predict poor outcomes to chemoimmunotherapy. This study was discussed at today's American Association for Cancer Research (AACR) annual meeting in Washington, DC together in addition to 8 other presentations covering advances in clinical and pre-clinical research with ibrutinib. The Phase II study, which was sponsored by the National Heart, Lung and Blood Institute, included an analysis of two CLL patient cohorts: the elderly, above 65 years of age, (n=24, of which 8 were treatment naive) and the high risk genetic group with a deletion of chromosome 17p (del 17p) (n=29, of which 15 were treatment naive). Many elderly patients with CLL are unable to tolerate aggressive therapies. Patients with deletion of chromosome 17p typically are poor responders to chemoimmunotherapy and have limited treatment options with no standard of care defined. Of all CLL patients enrolled in this trial, 72% had been characterized as Rai stage 3-4, indicating an advance stage, high risk patient population. The results of the study were presented by lead investigator Adrian Wiestner, M.D., PhD, Hematology Branch, NHLBI, National Institutes of Health. "Ibrutinib was highly efficacious as a single agent in patients with untreated, relapsed and unresponsive CLL, irrespective of their del 17p status," Dr. Wiestner said. "Responses in this study appear to be durable, and results indicate 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 in these tissue sites. Targeted therapy for CLL is becoming a reality, and this new approach may greatly improve the lives of patients with this disease." The study also evaluated in vivo effects of ibrutinib using blood and tissue samples collected before and during treatment. Ibrutinib demonstrated rapid and sustained disease control in blood, lymph nodes, spleen and bone marrow. After 6 months, 95 percent of patients experienced a reduction in lymph node size and all showed reduction in spleen enlargement, with a median reduction of 55 percent. In 26 patients, for whom a bone marrow biopsy was done, tumor infiltration decreased by 82 percent.