A look at recent failures in Pfizer research on drugs for pain, cancer, Alzheimer’s disease

A look at recent failures in Pfizer drug research

The failure of Pfizer Inc.’s tanezumab in a study of osteoarthritis patients is the latest in a string of disappointments on promising drugs that didn’t work well or showed safety problems after making it through years of expensive testing:

—Last week, two small companies partnering with Pfizer to develop multiple pain drugs said those compounds failed in mid-stage studies.

On Friday, Adolor Corporation said two experimental pain treatments for osteoarthritis of the knee, ADL5747 and ADL5859, didn’t work. Adolor and Pfizer are deciding whether to continue testing them for chronic inflammatory pain.

On Monday, Trubion Pharmaceuticals Inc. said Pfizer ended development of one experimental drug for rheumatoid arthritis, PF-05212374, that didn’t work well. The companies plan to keep testing a second such drug.

—In a major setback, a potential blockbuster Alzheimer’s disease drug that Pfizer and a partner were developing, Dimebon, in March failed in a late-stage study to keep symptoms from worsening. Two other studies of Dimebon continue — in combination with other Alzheimer’s drugs and in patients with Huntington’s disease — and might salvage the drug.

—Sutent, a pill approved for kidney cancer and gastrointestinal cancer, failed this spring in testing against two other types of cancer. In April, Pfizer stopped a late-stage study in liver cancer patients because they were dying faster than the group taking an existing drug. In March, Pfizer said Sutent did not meet goals in two late-stage studies for advanced breast cancer.

—In April 2009, Pfizer stopped another late-stage study of Sutent for advanced breast cancer because it didn’t improve survival rates.

—In January 2009, Pfizer stopped development of a drug for advanced pancreatic cancer, axitinib, in late-stage testing. It wasn’t improving patients’ survival.