New York, Dec 7 (IANS): Older adults with chronic lymphocytic leukemia, a type of slow-growing blood cancer, may have a better alternative to toxic chemotherapy as their first treatment, results of a phase three clinical trial show.

The findings showed that a newer, targeted drug, ibrutinib, is significantly more effective than traditional chemotherapy with chlorambucil in treating older patients with chronic lymphocytic leukemia (CLL).

The study, which followed 269 patients, revealed a 24-month overall survival rate of 97.8 percent for patients taking ibrutinib versus 85.3 percent for those on chlorambucil.

Minor adverse effects were reported.

"Ibrutinib was superior to chlorambucil in CLL patients with no prior treatment, as measured by progression-free survival, overall survival, and response" said lead researcher Jan Burger from The University of Texas MD Anderson Cancer Centre in the US.

"The study also revealed significant improvements in hemoglobin and platelet levels," Burger noted.

CLL is a disease of B lymphocytes, immune cells that originate in the bone marrow, develop in the lymph nodes, and which fight infection by producing antibodies.

"CLL is the most common adult leukemia in western countries, and primarily affects older patients with a median age of 72 years at diagnosis," Burger said.

"In many countries, chlorambucil has remained the standard first-line therapy for such patients since the 1960s. This study paves the way for the use of ibrutinib in the front-line therapy setting," Burger noted.

Ibrutinib is currently approved to treat CLL patients who have already received at least one other drug - but this was the first study to test its use as an initial therapy.

The findings were published in the online issue of the New England Journal of Medicine.