The stock ended at Rs 3,613.25, up 3.48 per cent on the BSE. During the day, it gained 3.67 per cent to Rs 3,620.
The scrip was the top gainer among the 30-Sensex stocks.
On the NSE, it rose by 3.6 per cent to settle at Rs 3,622.45.
The company's market valuation went up by Rs 2,046.93 crore to Rs 61,536.93 crore.
The Hyderabad-based firm has partnered with Spain's Ferrer Internacional SA to make Somazina available in India, Dr Reddy's Laboratories Ltd had said in a statement on Friday post market hours.
It is indicated for improving cognitive function in patients who have suffered from stroke or cerebral infarction, or who have undergone a brain surgery or have suffered from head injuries.
In the broader market, the BSE index Sensex closed the day with a sharp gain of 363.30 points at 27,687.30.