Patients with liver impairment receiving the drug erlotinib (Tarceva) should be closely monitored during therapy, according to an announcement posted September 23 by the U.S. Food and Drug Administration (FDA) on the MedWatch section of its Web site. The announcement followed a letter of warning from the drug's manufacturer, Genentech, Inc., and the developing company OSI Pharmaceuticals, Inc.

Erlotinib selectively slows the growth of cancer cells by targeting the epidermal growth factor receptor, which is often overexpressed by tumors. It was first approved by the FDA for treatment of non-small-cell lung cancer in 2004, and its approval was extended to pancreatic cancer patients as a combination therapy with gemcitabine in 2005.

Data from a pharmacokinetic study of the drug now show a high risk of liver failure in patients who have advanced solid tumors and moderate liver impairment. Among the 15 patients who were enrolled in the study - 10 of whom died during treatment - 6 had bilirubin levels (a marker of liver function) that were more than three times higher than the upper-limit of what is considered normal range. There was one case of hepatorenal syndrome (kidney failure following liver failure) and one case of rapidly progressing liver failure.

 "All [of the patients who died] had hepatic impairment due to advanced cancer with liver involvement such as hepatocellular carcinoma, cholangiocarcinoma, or liver metastases," the letter states, noting that a scoring system normally used to categorize liver function and injury in patients who have cirrhosis or other chronic liver disease - the Child-Pugh Score - has limitations for oncology patients.

The drug label for erlotinib has been updated to indicate that patients who have bilirubin levels more than three times higher than normal, or transaminase levels more than five times higher than normal, should not receive the drug. Patients who have any type of liver impairment should be monitored closely while taking erlotinib, the label states.

More details can be found online at http://www.fda.gov/medwatch/safety/2008/Tarceva_PI_DearHCPLetter.pdf.