The U.S. Food and Drug Administration (FDA) has asked India’s Sun Pharmaceutical Industries Ltd to halt tests on one dose of an experimental dermatological drug due to the potential of blood clots, the company said on Tuesday.

The FDA has also said that patients with alopecia areata – an autoimmune condition that results in patchy hair loss – on the 12 mg dose of the drug deuruxolitinib should discontinue its use, Sun Pharma said.

However, there were no thrombotic events, or blood clot formations, in patients taking the 8 mg dose and the FDA has not placed those trials on hold, Sun Pharma said.

The company said it would work closely with the FDA to address the agency’s concerns, which the drugmaker expected to be communicated within the next 30 days.

Sun Pharma, India’s largest drugmaker by revenue, acquired deuruxolitinib when it bought U.S.-based Concert Pharmaceuticals for $576 million earlier this year.

This is Sun Pharma’s second run-in with the FDA in less than two weeks.

In late April, the company said it would need to, at the behest of the FDA, take “certain corrective actions” at its facility in Mohali before it could export from there to the United States. Sun Pharma’s shares were down 0.3% in morning trading, while the Nifty Pharma index was up 0.35%.