Sun Pharma's stock gained 2.49 per cent to Rs 812.10 on the BSE.
At the NSE, the scrip was up 2.62 per cent to Rs 813.20.
Under terms of the agreement, Sun Pharma will acquire worldwide rights of tildrakizumab for use in all human indications from Merck in exchange for an upfront payment of USD 80 million, the companies had said in a joint statement yesterday.
"Merck will continue all clinical development and regulatory activities, which will be funded by Sun Pharma. Upon product approval, Sun Pharma will be responsible for regulatory activities, including subsequent submissions, pharmacovigilance, post approval studies, manufacturing and commercialisation of the approved product," it had said.