Under pressure from US regulators, Pfizer again halts study of pain drug over safety issues

Pfizer halts third study of experimental pain drug

TRENTON, N.J. — Drugmaker Pfizer Inc. has stopped patient tests of an experimental drug for two types of pain at the request of federal regulators, just weeks after halting its testing in arthritis patients.

Pfizer was testing tanezumab in patients with chronic low back pain and with painful nerve damage from diabetes complications. Both were late-stage studies. For now, the two studies won’t add new patients and will have study participants stop taking their pills.

They were part of a program of nearly 20 patient studies of the drug, including several for osteoarthritis, a very common condition caused by wear and tear on the joints. That’s a potentially huge market as baby boomers age.

Monday’s move comes less than four weeks after safety problems led Pfizer to halt testing of tanezumab in patients with osteoarthritis because it worsened in some patients, requiring joint replacements. That decision also was due to pressure from the U.S. Food and Drug Administration.

New York-based Pfizer said the FDA made the new request after further review of reports of harm to patients with osteoarthritis. Pfizer said it will keep working with the FDA to decide how to handle all future human testing of the drug.

The study failures are part of a worrisome trend at Pfizer, which is the world’s biggest drugmaker by revenue and spends about $9 billion a year trying to develop new drugs.

In the last 18 months, about a dozen studies of experimental drugs Pfizer was testing for Alzheimer’s disease, or various types of cancer and pain, failed because of poor efficacy or safety problems not seen in years of prior research. The Alzheimer’s drug was highly anticipated, and doctors called the failure a big setback because many hoped it might be the first treatment to stop or reverse the mind-robbing disease.

Meanwhile, Pfizer faces generic competition at the end of next year for its blockbuster cholesterol fighter Lipitor, which brings in about $13 billion a year, nearly one-quarter of company revenue.

Pfizer spokesman Mackay Jimeson said one late-stage study of tanezumab for treating osteoarthritis patients has been completed. Two other late-stage osteoarthritis studies have finished treating patients and their data is being analyzed.

Other arthritis studies have stopped recruiting new patients and giving study participants medication.

Jimeson said three other nonarthritis studies — two for cancer pain and one for chronic pancreatitis — will continue, but they will exclude any arthritis patients.

Pfizer shares rose 17 cents to $14.73 in regular trading Monday, then fell 8 cents in after-hours trading.