A new drug from Pharmacyclics, Inc. shows promise in treating high-risk patients suffering from leukemia.

The drug, dubbed IMBRUVICA^® (ibrutinib), was reported to be associated with an 88 percent overall response rate with a median study time of 23.2 months in 16 patients with relapsed/refractory (R/R) high-risk chronic lymphocytic leukemia (CLL), a news release reported. 

The drug works by inhibiting a protein called Bruton's tyrosine kinase (BTK), which is a key molecule in the B-cell receptor signaling complex that facilitates the spread of malignant B cells. The drug blocks signals that prompt the malignant B cells to multiply.

The findings support further study of the effects of the drug in patients following allogeneic stem cell transplants (allo-HCT). 

"These data support that IMBRUVICA may be an effective treatment option for relapsed post-transplant CLL patients, and are consistent with findings from clinical studies in the overall high-risk CLL population," said Dr. Danelle James, head of oncology at Pharmacyclics. "Moreover, these data provide supportive safety information as we evaluate IMBRUVICA in post allo-transplant patients who are suffering from chronic GVHD."

The study investigators concluded IMBRUVICA was well tolerated in patients who had prior allo-HCT, and those who received the drug showed a similar safety profile to what was observed in the general  R/R CLL population. The most common adverse events were infections seen in six of the trial's participants.The researchers noted one patient in the trial developed one patient achieved resolution of graft-versus-host disease (GVHD), which is a difficult-to-treat post-transplant complication. 

The data was presented in an oral presentation at Stanford University at the American Society for Blood and Marrow Transplantation's 2015 BMT Tandem Meeting in San Diego, California.