Pfizer Arthritis Pill Raises Safety Concerns, FDA Staff Says

Pfizer Inc.’s experimental pill to treat rheumatoid arthritis, one of the company’s leading drug candidates, raised “serious safety concerns” in trials, U.S. regulators said today.

The pill, tofacitinib, carried increased risks of serious infections and malignancies, in particular a higher chance of lymphoma, Food and Drug Administration staff wrote. The agency released the report ahead of a May 9 meeting of FDA medical advisers who will review tofacitinib’s benefits and risks.

Rheumatoid arthritis is an autoimmune disease in which the body attacks itself. It causes deterioration of the joints, which can make basic tasks such as walking or holding items painful. The condition is treated with anti-inflammatory pills like Aspirin, or drugs that attack the disease directly by modifying the immune system.

The data the FDA saw also didn’t show that the pill stopped the disease from progressing, according to the staff report. “This is particularly important in determining the overall benefit-risk profile of tofacitinib, which is associated with serious safety concerns.”

About 1.3 million people in the U.S. had the disease in 2009, according to the National Institutes of Health. Early detection can help slow or stop its progression.

Pfizer rose less than 1 percent to $22.45 at the close of New York trading.

First New Pill

If approved, tofacitinib would be the first new pill for rheumatoid arthritis in a decade, according to Pfizer. It would be used in patients who have tried and failed on methothrexate or injections such as Abbott Laboratories’ Humira.

Pfizer, based in New York, is seeking approval for doses of five and 10 milligrams. The FDA report said that the higher dose wasn’t justified, though. The 10 milligram dose “is not supported by the design of the Phase 3 studies, controlled data or pre-determined analyses,” the report said.

The FDA is scheduled to rule on the pill by August.

Pfizer has said it would first market the drug to patients who have failed on the injectable treatments called TNF-inhibitors.

“That’s where the greatest unmet need exists today,” Geno Germano, Pfizer’s president of specialty care, said on a May 1 conference call. In a statement, Pfizer spokeswoman Kristen Neese said the company believed the data showed a “favorable benefit/risk profile.”

Don’t Respond

Pfizer estimates that 30 percent to 40 percent of rheumatoid arthritis patients don’t respond to the TNF-inhibitors, including Humira, which generated $7.9 billion in 2011, and Amgen Inc.’s Enbrel, which Pfizer shares some rights to. Humira and Enbrel were among the top seven best-selling medicines in 2010, according to data compiled by Bloomberg.

The drug may generate $1 billion in sales by 2015 if approved, said Mark Schoenebaum, an analyst with ISI Group in New York who has a buy rating on the stock. Most of the risk of a rejection by regulators involves safety, he said in a May 2 webcast with investors.

Tony Butler, an analyst with Barclays in New York, said in an e-mail today that the FDA’s negative view of the pill was “as expected.”

Investors mostly have priced the drug’s approval into the stock, Schoenebaum said. “We expected a tough AdCom and the summary and questions reflect the FDA’s hard look at both tofa’s efficacy and safety,” he said in a note to clients today.

“We see about a 5 percent downside to the stock, maybe $1, if the thing is completely rejected,” he said.

The FDA may take a stricter line on approval than it did with previous rheumatoid arthritis drugs, Schoenebaum said. “Because it’s not as much of an unmet medical need as it was a few years ago, the requirements have gone up,” Schoenebaum said.

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