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A Promising Prognosis

Drug industry expects big sales from a new class of cancer drugs

July 28, 2002|DENISE GELLENE | TIMES STAFF WRITER

Just days after Susan Nelson started taking an experimental lung-cancer medicine, she was able to laugh without triggering a long coughing fit. Soon, she could hike through the scrub-covered hills near her Riverside County home without losing her breath.

A chest scan taken five weeks after Nelson, 48, started treatment showed why she felt better: The once-daily pills had shrunk her tumors by 75%.

The cancer medicine used by Nelson is not yet for sale in the United States. It is in the final stages of clinical testing and could obtain government approval this year. It was cleared for sale in Japan this month.

Called Iressa, it is the first drug in a class that disrupts the molecular switches responsible for tumor growth. The switches, called epidermal growth factor receptors, or EGF-receptors, are found on two-thirds of solid tumors.

The drug, developed by British drug maker AstraZeneca, is in the same class as Erbitux, the experimental treatment engulfed in the ImClone Systems Inc. insider-trading controversy.

Iressa does not cure cancer, and, for reasons not understood, does not help every patient. In a company-sponsored study, the medicine shrank tumors by 50% or more in just 11% of patients with metastatic disease--cancer that had spread to the other lung or another organ. Four patients in 10 said they could breathe more easily after taking the drug.

The results are modest, but doctors are impressed. The patients who took Iressa in clinical trials were very sick and had tried two to three rounds of chemotherapy, toxic drugs that kill cancer cells but make patients feel worse. Few patients with advanced disease respond to medication, said Dr. Roy Herbst of the M.D. Anderson Cancer Center in Houston.

"It is the best thing we have seen in years," said Herbst, who conducted some of the trials.

Few medical experts expect EGF-receptor drugs to replace chemotherapy as the primary treatment for lung cancer, the leading cause of cancer death. But some doctors think the new drugs could be safely combined with chemotherapy to deliver a stronger blow to cancer cells early in the disease, when it will do the most good. Clinical trials to test that theory are underway.

EGF-receptor drugs offer great promise to an industry beset with patent expirations and a dearth of new products. As a group, these drugs could have peak sales of $4.5 billion, said David Bouchey, an analyst with C.E. Unterberg, Towbin. Iressa could account for $1.5 billion of that, he said.

Only one cancer drug, Bristol-Myers Squibb Co.'s Taxol, now off patent, has had sales of more than $1 billion.

Driving Bouchey's forecast is an assumption that the drugs will be used to treat several types of cancer. AstraZeneca and its competitors are testing the therapies in cancers that affect the colon, pancreas, head and neck. Taken together, those cancers affect nearly as many Americans as lung cancer. Beyond that, AstraZeneca said, it is conducting more than 100 "exploratory trials" in other cancers in which Iressa might prove effective.

AstraZeneca is the front-runner in the race to market because of missteps by ImClone Systems. In December, the Food and Drug Administration rejected ImClone's application to market Erbitux, citing numerous flaws in the company's data--a setback that pushed Erbitux to third place. The company's former chief executive, Samuel D. Waksal, faces insider-trading charges for allegedly tipping off relatives to the bad news before the FDA action became public knowledge.

Iressa's closest competitor is Tarceva, an EGF-receptor drug being developed by OSI Pharmaceuticals Inc., Genentech Inc. and Roche Group, which is expected to reach the market by mid-2004. Trailing them are Abgenix, Pfizer Inc., Wyeth and GlaxoSmithKline, which have EGF-receptor drugs in development.

AstraZeneca Chief Executive Tom McKillop last week stood by his prediction that Iressa would reach the U.S. market this year. He said the company will complete its marketing application in August and expects FDA approval in the fall. But analysts said the timing is tight and AstraZeneca is months behind schedule in filing paperwork with the FDA. They said the launch of Iressa could be delayed until early next year.

Stephens Inc. analyst Jason Y. Zhang said the FDA could delay its decision until it sees the results from two large clinical trials designed to measure whether patients on Iressa live longer. The trials compare 1,000 patients on Iressa and standard chemotherapy with 1,000 others on chemotherapy alone. McKillop told analysts that the outcome of those trials won't be known until later this year.

No Serious Side Effects

Evidence that a drug improves survival is the gold standard for approval. The FDA rejected oxaliplatin, a chemotherapy drug developed by French drug maker Sanofi-Synthelabo, because it was not more successful at extending patients' lives than existing drugs. Sanofi currently is testing a cocktail of oxaliplatin and other drugs.

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