Stifel analyst Adam Walsh said the USPTO ruling that the claims of Concert Pharmaceuticals' patent covering composition of matter for CTP-543 is not patentable significantly reduces his expected duration of market exclusivity upon approval to 5.5 years from his previous assumption of protection out to 2033. Given this lowered exclusivity assumption, he cut his price target on Concert shares to $18 from $27. However, Walsh keeps a Buy rating on the stock and said the recent selloff seems overdone given his view on several near-term potential catalysts.