Genentech Inc. and OSI Pharmaceuticals, the makers of Tarceva - a cancer drug, in a letter posted on the Food and Drug Administration’s website at http://www.fda.gov/medwatch/safety/2008/safety08.htm#Tarceva, alerted doctors about liver damage in patients who took the drug, as part of a post-approval study designed for patients with moderate liver impairment and advanced tumours.

The two deaths related to Tarceva saw one patient dying from rapidly progressing liver failure, while the other developed a fatal liver complication called hepatorenal syndrome, leading to his death.

Also known by its generic name Erlotinib, Tarcevera’s global sales hit $866-million in 2007.  An oral drug, Tarceva had been approved for treating certain patients with lung or pancreatic cancer. Charlotte Arnold, Genentech spokeswoman says most of the 36-patients participating in the post-approval study had types of tumours that had not been approved for treatment with Tarceva.

According to Arnold, the drug’s prescribing information included a precaution about liver damage and fatalities, but now there will be stronger warning on its label.

Shares of Melville, N.Y.-based OSI added 17 cents to $46.54 in afternoon trading, while South San Francisco-based Genentech fell 83 cents to $91.47.