The US Patent and Trademark Office has rejected a petition filed in July last year by Concert Pharmaceuticals challenging a patent awarded to Incyte Pharmaceuticals.
Shares in the East Coast-based firm are down almost a quarter in morning trading on the Nasdaq.
Chief executive Roger Tung said: “We are disappointed that the PTAB has denied our petition on the ’335 patent.”
“This decision does not prohibit us from challenging the validity of the patent at a later time in federal court, and we will continue with our plans to develop CTP-543 for alopecia areata. We don’t expect any disruption to our clinical timelines.”