FDA notes cancer cases linked to Regeneron gout drug

Regeneron Pharmaceuticals' ($REGN) Arcalyst heads to an FDA panel next week as a new treatment for gout flare-ups after a mixed review of the drug in FDA staff documents released Friday. The drug developer is seeking an expanded approval of the drug, previously OK'd for combating rare genetic auto-inflammatory conditions, for use in certain patients with the much more common ailment.

The FDA staff review questioned whether the risks of the treatment overwhelm the benefits of the drug in fighting gout flare-ups, saying that the drug provided only a "small" benefit and pointing out that 6 patients studied developed malignancies, Bloomberg reported. Regeneron wants approval for Arcalyst to treat gout patients during a 16-week period when they are open to attacks from the disease and initiating uric-acid lowering treatment.

"From an efficacy standpoint, it will be important to address whether 16 weeks provide for an adequate duration for flare prophylaxis during initiation of (uric acid-lowering therapy)," the FDA staff said in review documents, as quoted by Reuters. The news service also reported that reviewers noted that the immune-suppression of the biologic could be linked with the cancer cases, but they were uncertain whether the relatively short duration of treatment on the drug could cause malignancies.

Regeneron's shares were down 1.37% to $132.08 as of 11:57 a.m. ET today.

The additional approval for Regeneron's drug could significantly grow revenue from sales of the product, which were just $20 million last year but could jump to more than 10 times that total by 2015 with the gout indication, Bloomberg reported, citing data and analyst estimates.

- see Bloomberg's article
- and Reuters' coverage