TOKYO — More than three dozen patients in Japan have died from side effects after taking a cancer-fighting drug made by Anglo-Swedish company AstraZeneca, and Japanese health authorities were expected to investigate, a company spokeswoman said Sunday.
The drug, Gefitinib, has caused debilitating lung injuries such as interstitial pneumonia in 125 patients, including the 39 who have died, said spokeswoman Fumiko Muramoto.
"We knew about the possibility of these side effects from our clinical trials," Muramoto said. "But the number of safety incidents is increasing very rapidly. It's alarming, and that's why we're issuing the warnings."
Japan is the only country that has approved Gefitinib for advanced non-small-cell lung cancer. The Food and Drug Administration is reviewing London-based AstraZeneca's application to sell the drug in the United States, as are Swiss drug regulators.
Gefitinib, sold under the Iressa brand, has been taken by at least 10,000 cancer patients since it was cleared for use in Japan in July, Muramoto said.
She said Japan's Health, Welfare and Labor Ministry plans to investigate the company's Osaka-based subsidiary. Health ministry officials could not be reached for comment.
On Oct. 15, AstraZeneca issued a safety warning to doctors after the company received reports of severe side effects in 22 patients, including 11 who died, Muramoto said. The company later raised the figure to 26 affected patients, including 13 deaths.
At that point, she said, the company had reports of 65 cases of side effects, including 27 deaths, but had not gone through all the cases to confirm their link to the drug. She said the company reported only the confirmed cases at the news conference, and it took 10 more days to give the final results to the health ministry.
Muramoto said the company had reported the figures within the 30 days required by law and had no intention of concealing the problems.
"But the health ministry has made it clear they are not happy with the slow pace of reporting cases," Muramoto said, adding that the company was trying to speed up its filings.