A key drug in Pfizer Inc.'s pipeline will be scrutinized by an advisory panel starting today after a U.S. Food and Drug Administration staff report raised questions about patients' increased risk of lymphoma, infections and other serious events.
Tofacitinib, a rheumatoid arthritis pill advanced largely by Pfizer's Groton laboratories, will be reviewed by FDA medical advisers given the task of weighing the drug's risks and benefits.
An FDA staff report, released earlier this week, cited "serious safety concerns" with tofacitinib, the most concerning of which may have been the increased risk of patients developing malignancies as they increased their exposure to the drug.
But Leerink Swann analyst Seamus Fernandez, in a research note, said experts he consulted believe the concerns over tofacitinib are overblown.
"We believe tofacitinib will be recommended by the panel," he said. "The agency may be trying to manage the (drug) label and limit initial utilization until long-term safety is better characterized."
The FDA staff report, which is intended as talking points for the panel to address, also noted that tofacitinib did not appear to stop the progression of rheumatoid arthritis in patients.
"This is particularly important in determining the overall benefit-risk profile of tofacitinib," the report said.
Rheumatoid arthritis is an autoimmune disease that affects an estimated 1.3 million people in the United States. Its hallmark is joints aches.
According to a Bloomberg report, tofacitinib is expected to reach the $1 billion blockbuster status by 2015 if approved for sale by the FDA. Regulators are expected to make a final determination by August.
Tofacitinib would be recommended for the estimated 30 percent to 40 percent of rheumatoid arthritis sufferers who don't respond to injectable treatments such as the $7.9 billion Humira.