Allergan plc (NYSE: AGN) has agreed to acquire Vitae Pharmaceuticals Inc. (Nasdaq: VTAE) in a deal valued at nearly $639 million.  Allergan will pay the target $21 per share. The deal is expected to close by the end of 2016.

Vitae’s products will be “poised for successful development as part of Allergan’s portfolio,” according to Vitae chief executive officer Jeff Hatfield. The acquisition is a “strategic investment for Allergan that adds strength and depth” to the company’s medical dermatology pipeline, according to Brent Saunders, chief executive officer at Allergan. The deal brings both Vitae’s VTP-43742 and VTP-38543 products to Jersey City, Jersey-based Allergan. The former is a potential treatment for autoimmune diseases and recently completed  clinical trials, while the latter helps treat damaged skin layers and is now going through clinical trials.

David Nicholson, chief development officer at Allergan, says “action for the treatment for dermatologic conditions” is “underserved by currently approved treatments.” He adds that Vitae’s drug, Contour, will be “highly complementary” to Allergan’s existing research and development efforts. Saunders commends Fort Washington, Pennsylvania-based Vitae for its research in “areas of medicine where innovation is needed for patients.”

This deal follows Allergan’s terminated merger with Pfizer Inc. (NYSE: PFE), mainly due to the U.S. Treasury Department proposing new tax rules to deter inversions. As for other pharmaceutical deals, Sunovion Pharmaceuticals Inc. agreed to acquire Cynapsus Therapeutics Inc. (Nasdaq: CYNA) (TSX: CTH) in September for an estimated $624 million. In July, Nichi-Iko Pharmaceutical Co. agreed to pay $736 million in cash for Sagent Pharmaceuticals Inc. (Nasdaq: SGNT) to grow its presence in the U.S.

JPMorgan Chase & Co. (NYSE: JPM)  and Gunderson Dettmer Stough Villeneuve Franklin & Hachigian LLP will serve as financial adviser and legal counsel to Vitae, respectively. Debevoise & Plimpton LLP will serve as Allergan’s legalcounsel.