Drugmaker Shire P.L.C., with operations in Exton, has licensed an experimental treatment for dry-eye disease from a Durham, N.C. biopharmaceutical company. Shire agreed to a $20 million up-front payment to Parion Sciences, and will pay an additional $20 million based on achieving near-term development milestones. The potential deal value could be as much as $535 million for Parion, the companies said Monday.

The molecule, P-321, has showed promise in midstage Phase 2 patient studies in blocking the absorption of tears and helping keep the surface of the eye hydrated. Under the agreement, Shire will have worldwide development and commercialization rights. "Ophthalmics is a continued focus for Shire," said Shire's chief executive officer, Flemming Ornskov. Parion Sciences CEO Paul Boucher said Shire "offers the expertise and resources to move this promising potential therapy for dry eye sufferers forward." Shire has U.S. headquarters in Lexington, Mass., and employs 550 in Exton.