Successful Tarceva Study Sends Shares Skyward

Enzyme Blockers

An oral drug, Tarceva is a member of the closely watched class of drugs that attempts to halt the growth of cancer cells by blocking a key enzyme, epidermal growth factor receptor, or EGFR. In this way, Tarceva is very similar to AstraZeneca's Iressa, which was the first of these EGFR inhibitors to be approved in the U.S. last year, also for late-stage non-small cell lung cancer patients. ImClone's (IMCL Quote) Erbitux is also an EGFR inhibitor, but it's an injectable drug, so it works in a slightly different way.

The phase III Tarceva study enrolled about 700 non-small cell lung cancer patients who failed all approved drugs and had no other good medical treatment options. These patients were split into two groups; one group was given Tarceva, while the other group (the control) was treated with the standard "best supportive care."

As long as the actual data confirm Sunday's findings, Tarceva will most likely be viewed as superior to AstraZeneca's Iressa. The Tarceva study is the first controlled study of an oral EGFR drug to demonstrate that it can boost the survival of advanced non-small cell lung cancer patients. The studies used to approve Iressa only showed that the drug shrank tumors in about 10% of patients; they were not designed to look at changes in survival. Last year, AstraZeneca reported worldwide Iressa sales of $228 million.