Here's Why Regeneron Pharmaceuticals Inc. Slipped 10% in October

Shares of Regeneron Pharmaceuticals Inc. (NASDAQ: REGN) took a hit last month as investors adjusted their outlook for a recently launched eczema drug with megablockbuster potential. According to data from S&P Global Market Intelligence, the stock slid 9.95% in October as investors fretted about Dupixent's ongoing commercial launch in light of surprisingly strong data from a potential competitor.

Dupixent is a twice-monthly injection expected to generate around $5 billion in annual sales by 2022 as a treatment for patients with moderate to severe cases of eczema and hopefully asthma. In September, Regeneron and its big pharma partner, Sanofi (NYSE: SNY), released late-stage data from an asthma trial that was good but not great. The observed 46% annual attack rate reduction might earn an approval for the indication, but it wasn't dramatic enough to make a big splash in a pool crowded with effective treatment options.

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Source: Fool.com