) Erbitux. This experimental drug was expected to be the first in a group of treatments that block tumor-growth signals. Doctors left the meeting enthusiastic, patients besieged ImClone with requests for Erbitux even though it had yet to win Food & Drug Administration approval, and investors bid up the company's stock.
That was then. ImClone's application for Erbitux was famously rejected by the FDA in December because the data were incomplete and the trial flawed. But tumor-growth signals are still front and center in fighting cancer. The star of this year's ASCO, to be held May 18-21 in Orlando, is a rival to Erbitux called Iressa, from AstraZeneca PLC. It targets the same growth factor, and it's being tested against many of the same cancers. Results on the two drugs are even being presented back-to-back at the meeting. But while Erbitux is not expected to win FDA approval until mid-2003 at the earliest, Iressa could get the nod this summer.
The operative word here is "could." The Erbitux debacle has led to a cautionary mood among ASCO participants, so talk of Iressa is couched in qualifiers. Much of that hesitancy arose after AstraZeneca (AZN
) decided, in March, not to present the results of two late-stage clinical trials of the drug at ASCO because it hadn't finished compiling the data, raising concerns that there may be a problem. The company says there isn't, and Robertson Stephens analyst Jason Zhang notes that "the clinical-trial data so far for Iressa are pretty convincing." Still, he adds: "Being mindful of everything that happened with Erbitux, [it] could be a tough call" as to when the FDA will O.K. the drug.
The timing of the FDA's Iressa ruling is of urgent interest. Analysts assume that whichever drug is available first will grab a larger share of the market. Both drugs, which are relatively free of side effects, block epidermal growth factor, a protein that signals cancer cells to grow and spread. Although neither is considered a cure, both can stop tumors from metastasizing--in essence turning cancer into a chronic, treatable disease. Given that cancer kills 1,500 people a day in the U.S., that could be a big breakthrough.
Iressa, if approved, will be used initially to treat lung cancer, while Erbitux would be deployed against colon cancer. Those are the two biggest killers among cancers, and there is no effective treatment for either once the disease starts to spread. Moreover, both drugs are being tested against a broad range of cancers. If they work, demand could be more than $1 billion a year.
Right now, all eyes are on Iressa. AstraZeneca's application was accepted by the FDA on the same day in December that the agency rejected Erbitux, and Iressa is guaranteed a review within six months. The filing is based on two midstage clinical trials, which tested the drug on 200 lung-cancer patients who had failed chemotherapy. Astra-Zeneca has already reported that the tumors of 18% of those patients shrank, a good result for advanced disease. The results will be updated at ASCO.
Still, cancer experts warn that the FDA prefers to hand out approvals based on trials that show a drug extends life, as opposed to just shrinking a tumor. That explains the disappointment over AstraZeneca's decision not to present late-stage trial data at ASCO. Those two tests, designed to measure survival, enrolled 2,000 previously untreated lung-cancer patients. Dr. Roy Herbst of M.D. Anderson Cancer Center in Houston, a lead investigator of the trials, says they went quite well: He expects the data to be ready by yearend.
ImClone is also presenting data at ASCO, and analysts are hoping to pick up clues about the drug's chances with the FDA. Of particular interest will be a large trial against cancers of the head and neck, conducted by ImClone's partner, Merck of Germany. "If the data are good, I think ASCO should help ImClone," says Sanford C. Bernstein & Co. analyst Catherine J. Arnold. But again, no one is in any position to say for sure. By Catherine Arnst in New York