Cancer Medication Iressa Does Not Extend Patient Survival Times, Could Face Market Removal
AstraZeneca's targeted cancer drug Iressa does not prolong the lives of people with advanced lung cancer "by a meaningful amount," according to clinical trials published Friday, and FDA officials are considering removing the drug from the market, the New York Times reports. AstraZeneca will cease marketing the drug to physicians.
Iressa was approved in May 2003 under fast-track review after clinical trials showed the drug reduced tumors in about 10% of patients whose cancer was unaffected by other treatments (Pollack, New York Times, 12/20). Iressa, which is in the epidermal growth factor receptor inhibitor class of drugs, was approved as a second or third treatment for patients with advanced lung cancer (Vrana, Los Angeles Times, 12/18).
FDA approval of the drug was contingent on future trials conducted by AstraZeneca to show that the drug could prolong lives. A recently completed trial of 1,700 patients showed that those taking Iressa had a median survival of 5.6 months, compared with 5.1 months for those that took a placebo.
According to the New York Times, the trial results are "expected to mean much larger sales of Tarceva," a similar lung cancer drug approved last month and manufactured by OSI Pharmaceuticals and Genentech. In a clinical trial, patients with lung cancer who were given Tarceva had median survival of 6.7 months, compared with 4.7 months for those who were given placebos (New York Times, 12/20). In addition, 31% of patients who took Tarceva in the trial were alive after one year, compared with 22% of those who took placebos (Szabo, USA Today, 12/20).
According to the New York Times, researchers are investigating using genetic tests to determine in advance of treatment which patients could benefit from Iressa. A trial conducted earlier this year by two groups of researchers in Boston showed that some genetic mutations in tumor cells correlate with the drug's effectiveness (New York Times, 12/20). Iressa accounted for $309 million of AstraZeneca's $15.6 billion sales in the first nine months of 2004 (Los Angeles Times, 12/18).
In a conference call with investors on Friday, AstraZeneca CEO Tom McKillop said that the company would conduct a full review of its procedure for conducting clinical trials and submitting drugs for regulatory approval. Such a review could examine testing different doses of a drug in late-stage clinical trials "to ensure the company isn't missing the correct dose," the Wall Street Journal reports.
McKillop noted that he did not believe that the recommended dosage for Iressa was incorrect. He also said the company might consider communicating with regulatory officials at an earlier stage in the approval process to determine if a drug has potential side effects or other problems. McKillop said it was too early to know whether Iressa would be removed from the market.
"We've put enormous importance on innovation and creativity. I'm not sure we've been really taking apart out clinical programs to see where are all the risks and have we really minimized all the risks," McKillop said (Wall Street Journal, 12/20). He added, "Clearly it will be apparent to all of you that this has been a very difficult, challenging year for the company" (New York Times, 12/20).
American Society of Clinical Oncology President David Johnson said, "This comes as an enormous surprise to everyone" (USA Today, 12/20).
Clariden Bank analyst Eric Bernhardt said, "We were expecting more from Iressa and thought it would be a close fight between Tarceva and Iressa. It's a big setback. It shows this product really has a problem" (Los Angles Times, 12/18).
Roy Herbst, chief of thoracic oncology at M.D. Anderson Cancer Center, said, "If we can understand why one is better than another, that could be the key to developing an undiscovered third drug. It makes you realize how much more we need to learn" (USA Today, 12/20).
Steve Walker, an Abigail Alliance for Better Access to Developmental Drugs adviser, said that Iressa should remain on the market for those who might benefit from the drug. He added that it is not realistic to require a drug that is known to provide a major benefit to a limited number of people to show a significant advantage in the entire population (New York Times, 12/20).
Genentech spokesperson Kristina Becker said, "It would be premature to comment on a potential price increase" for Tarceva. She added, "We're just glad there's an option out there for patients" (Los Angeles Times, 12/18).