Regeneron Drug’s Benefit May Not Outweigh Risk, FDA Says

Regeneron Pharmaceuticals Inc.’s Arcalyst may not offer enough of a benefit in preventing gout flares to be worth the risk of developing cancer, U.S. regulators said.

Arcalyst lowered the number of gout flares in final-phase studies, yet the benefit was “small,” Food and Drug Administration staff wrote in a report released today. The drug also is associated with a small increased risk of malignancy, the staff wrote. The agency is scheduled to convene advisers on May 8 to weigh expanding approval of the medicine.

Regeneron studied the drug in gout for 16 weeks, the time it anticipates patients will take Arcalyst to prevent flares during their most-vulnerable period. The lack of long-term safety data for such a medicine isn’t typical, FDA staff wrote. If approved for wider use, Arcalyst sales may reach $209 million in 2015, with $164 million coming from gout use, according to the average of two analyst estimates compiled by Bloomberg.

While the expanded use of Arcalyst in gout would be a “modest” contributor, gaining that clearance and an approval the drugmaker is seeking for a cancer drug “would increase investor confidence” in Regeneron’s ability to function as a multiproduct company, Jason Kantor, an analyst with RBC Capital Markets in San Francisco, wrote April 26 in a note to clients.

Regeneron, based in Tarrytown, New York, fell 1.9 percent to $131.40 at the close in New York. The company’s shares have more than doubled in the past 12 months.

Six Cases

Arcalyst was linked to six cases of malignancies, including prostate and breast cancers. FDA staff determined for every 244 patients treated with Arcalyst, one would develop a malignancy.

FDA staff also said that Regeneron conducted studies on patients capable of taking other treatments including anti-inflammatories and colchicine.

The agency’s deadline to decide whether to approve Arcalyst is July 30.

Gout treatments include Takeda Pharmaceutical Co.’s Uloric and a generic version called allopurinol. They lower levels of uric acid, or bodily waste, that cause gout in excess levels, which manifests through joint pain, according to the National Institutes of Health. Regeneron is seeking approval of Arcalyst to prevent gout flares for people initiating uric-acid lowering therapies.

Allopurinol breaks up uric acid crystals that can cause flares of joint pain that may lead patients to stop taking their medication, the company said. About 750,000 gout patients begin taking allopurinol each year, according to Regeneron.

Weekly injections of Arcalyst reduced gout flares in final-phase clinical trials and patients tolerated the drug well, experiencing infections at a rate similar to those who took placebo.

The drug was approved in February 2008 to treat a rare genetic autoinflammatory disease known as Cryopyrin-Associated Periodic Syndromes. Arcalyst generated in $20 million in sales last year, according to data compiled by Bloomberg.

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