“Drugmaker Pfizer has stopped patient tests of an experimental drug for two types of pain at the request of US regulators.  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 participants will stop taking their pills.  They were part of a program of almost 20 patient studies of the drug, including several for osteoarthritis.  The 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 US 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 worrying trend at Pfizer, which is the world’s biggest drugmaker by revenue and spends about $US9 billion a year trying to develop new drugs.  In the past 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 disease”

Meanwhile, Pfizer faces generic competition at the end of next year for its blockbuster cholesterol fighter Lipitor, which brings in about $US13 billion a year, almost a quarter of its revenue.