Pfizer has identified the drug, known as tofacitinib, as one of the most promising and lucrative prospects in its drug pipeline. The company is struggling to regain lost sales after its best-selling cholesterol drug, Lipitor, lost patent protection last fall.
An advisory panel to the Food and Drug Administration is scheduled to vote on whether to recommend approval of the drug on Wednesday. The agency is then expected to rule on the drug by August.
In a statement Monday, the company said the drugâ€™s benefits outweighed its risks, and â€śwe look forward to discussing tofacitinib with the committee on Wednesday.â€ť
The briefing documents, prepared by F.D.A. staff members and released Monday ahead of the meeting, also found that although tofacitinib did ease the symptoms of rheumatoid arthritis and the physical functioning of those who have it, the studies didnâ€™t definitively show that the drug stopped the disease from progressing. â€śThis is particularly important in determining the overall benefit-risk profile of tofacitinib, which is associated with serious safety concerns,â€ť the report found.
Rheumatoid arthritis is a chronic autoimmune disease that attacks the bodyâ€™s joints, causing painful swelling and difficulty moving. A handful of biologic drugs, like Humira and Enbrel, exist to treat the disease but they must be injected. Pfizerâ€™s oral pill is to be used in patients who donâ€™t respond to other drugs.
In a conference call with analysts last week, a Pfizer executive hinted that questions about safety would probably come up because the drug acted on the body in a new way. â€śOn the risks side, this is a new mechanism of action, so thereâ€™ll be lots of interest in understanding the profile thoroughly,â€ť said Geno J. Germano, who is in charge of specialty care and oncology at Pfizer. â€śThe safety events are familiar to rheumatologists. Theyâ€™re manageable in most cases.â€ť
Most of the rheumatoid arthritis drugs on the market carry similar risks, said Dr. John H. Klippel, a rheumatologist and president of the Arthritis Foundation. â€śPeople who have that disease, in general, are willing to accept the risk of even serious adverse effects from drugs if they can find drugs that are going to alter the course of the disease,â€ť he said.
If tofacitinib is ultimately approved, he said it would represent a â€śhuge advanceâ€ť because it targets the disease in a new way and will be available as an oral pill. The drug inhibits production of an enzyme implicated in immunological diseases like arthritis.
Les Funtleyder, a portfolio manager for Miller Tabak, cautioned against drawing too many conclusions from Mondayâ€™s report. â€śBriefing documents tend to accentuate the risks and itâ€™s not until you get to see the whole panel discuss it that you really hear what people think is important,â€ť said Mr. Funtleyder, whose fund owns Pfizer stock. The fact that the drug did not stop progression of the disease may not be a serious impediment to getting it approved, he said. If people who use the drug feel better and are able to walk, he added, â€śdoes it really matter?â€ť