Parion Sciences Inc., of Durham, N.C., and Osaka, Japan-based Santen Pharmaceutical Co. Ltd. agreed to jointly develop and commercialize Parion's experimental treatment for dry eye disease, P-321, in parts of Asia. Under the deal's terms, Santen will make an undisclosed option payment to secure certain rights to P-321 and to support the upcoming combination phase I/IIa trial of the drug.