Schering-Plough Research Institute (SPRI) reported that it has voluntarily stopped enrollment in its Phase III clinical study of Sarasar (lonafarnib) in non-small-cell lung cancer (NSCLC). An analysis of interim data from this study led to the conclusion that the study will not provide sufficient evidence of efficacy to warrant further enrollment.

SPRI emphasized that it is continuing its Phase II clinical studies of Sarasar in leukemia and a variety of solid tumours. Schering-Plough noted that other companies' anticancer compounds (trastuzumab and gefitinib) also have failed to show efficacy in their recent studies in first-line NSCLC.

Sarasar is a member of a new class of compounds called FTI's that take a novel approach to treating cancer by inhibiting farnesyl transferase, a key enzyme involved in the regulation of the growth and proliferation of cancer cells. Inhibition of protein farnesylation alters the activity of a number of proteins important in tumor cell proliferation, including the Ras oncogene family.

Schering-Plough Research Institute is the pharmaceutical research and development arm of Schering-Plough Corporation.