SUNNYVALE, Calif., Dec. 9, 2013 /PRNewswire/ -- Pharmacyclics, Inc. (NASDAQ: PCYC) today announced that The Lancet Oncology published results of a study evaluating ibrutinib in previously untreated elderly patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL). The Phase 1b/2 open-label, multicenter study evaluated 31 patients, 65 years of age and older with CLL or SLL. The primary endpoint of the study was safety, as assessed by the frequency and severity of adverse events (AEs), while the secondary objectives assessed the clinical activity of single agent ibrutinib. Only one patient out of the 31 enrolled in this cohort has had progression of disease.
After a median follow-up of 22.1 months (range, 18.4-23.2), the overall response rate (ORR) for patients was 71 percent (95% CI, 52-86), which included 55 percent partial response, 3 percent nodular partial response and 13 percent complete response. An additional 13 percent of patients achived a partial response with lymphocytosis. The median time to initial response was 1.9 months (range, 1.5-7.4); the median time to best response and complete response were 5.9 months (range, 1.8-22.1) and 12.0 months (range, 7.1-15.6), respectively.
Across all patients, the estimated progression-free survival (PFS) and overall survival at 24 months were 96.3 percent (95% CI, 76.5-99.5) and 96.6 percent (95% CI, 77.9-99.5), respectively.
"Older patients with CLL and SLL are at particularly high risk, and the standard of care therapies for these patients can often lead to significant and burdensome complications," said lead author Susan O'Brien, M.D., Department of Leukemia, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center. "There is a need for new treatment options, and we are encouraged by the high response rate and tolerability seen with ibrutinib as a first line therapy."The majority of AEs that occurred were mild and Grade 1 or 2 in severity. Diarrhea was seen in 21 of 31 patients (68%) and was grade 1 in 14 of 31 patients (45%), grade 2 in three patients (10%), and grade 3 in four patients (13%). There were no episodes of grade 4 diarrhea. Nausea was predominantly grade 1 (12 of 31 patients; 39%), with a maximum grade of 2 (three of 31 patients (10%). Fatigue was seen in 10 of the 31 patients (32%), including five patients (16%) with grade 1, four (13%) with grade 2, and one (3%) with grade 3. Grade 3 infections were noted in three of the 31 patients (10%); no grade 4 or 5 infections were observed. There was one grade 3 neutropaenia and one grade 4 thrombocytopaenia. Two patients discontinued treatment for adverse events that included grade 3 fatigue in one patient and grade 2 viral infection in a second patient.