Sun Pharma to seek FDA re-inspection of Halol plant by end-June

The letter means the U.S. agency could ban imports from the plant if the problems were not resolved.

The Halol factory makes up 15 percent of Sun Pharma's U.S. sales. However, the company has not received any U.S. approvals to launch new drugs made at Halol since Sept. 2014.

That has resulted in supply constraints that hurt the company's sales in the past year. U.S. sales fell 11 percent in the quarter ended Dec. 31, Sun Pharma reported on Friday.

However, its total profit of 14.17 billion rupees ($207.52 million) still outpaced analysts' estimates of 13.16 billion rupees, helped by an 8 percent rise in sales in India, and a 78 percent jump in sales of drug raw materials.

Supplies from the Halol site are gradually improving, Shanghvi told analysts on a conference call.

"We have undertaken some incremental remedial measures to address the issues, and we are progressing well on their implementation," the Indian billionaire said.

Sun Pharma's emerging markets sales fell by 7 percent in the third quarter due to currency volatilities.

Sun Pharma said it would not be materially affected by the dissolution of the joint venture with Merck. The companies' agreements to market the diabetes drug sitagliptin and their deal on Merck's experimental skin disease drug tildrakizumab would continue.

The firm's shares closed up 2 percent after rising as much as 7 percent earlier in the day in Mumbai. The broader market closed up 0.07 percent.