Shares of Sun Pharmaceutical Industries fell more than 1% on May 2 after the US Food and Drug Administration (USFDA) suspended part of its clinical application for an experimental dermatology drug due to a possible thrombotic event.

“Following a recent submission to the USFDA, we held a conference call with the agency to discuss pulmonary embolism (a serious adverse event) at the 12 mg BID dose in a long-term open-label extension (OLE) study,” the company said in a regulatory filing. “Therefore, the agency has placed the drug on partial clinical hold due to the possibility of a thrombotic event,” it added.

Shares of the company were trading down 1% at Rs 976.65 on the BSE at 12:12 pm.

The company said no thromboembolic events were observed during the phase 2 or 3 trials while adding that it remained confident in deuruxolitinib’s potential to treat patients with alopecia areata. USFDA is expected to address those concerns in a formal letter within the next 30 days.

The company’s website reads that Concert Pharmaceuticals is developing deuruxolitinib, an oral inhibitor of the Janus kinases JAK1 and JAK2, as a potential treatment for alopecia areata.

The company completed its acquisition of Concert Pharmaceuticals on March 6, adding deuruxolitinib to its global dermatology portfolio. The acquisition cost was $576 million ($8 per share).