US Food and Drug Administration (FDA) has halted Sun Pharmaceuticals Limited’s trials on dermatological drugs owing to the potential threat of blood clots, the company said in a regulatory filing on Tuesday. The federal agency has put on hold the trial of 12 mg of Deuruxolitinib clinical trial owing to a potential pulmonary embolism. Deuruxolitinib is an investigational oral selective inhibitor of Janus kinases JAK1 and JAK2, which is being studied for the treatment of Alopecia Areata.

"Following a recent submission to the US FDA, we had a teleconference call with the agency, regarding a pulmonary embolism (Serious Adverse Events) occurring at the 12 mg BID dose in one of the long-term Open Label Extension (OLE) studies. As a result, the agency has placed the IND on partial clinical hold, due to the potential for thrombotic events, and are requiring that subjects currently on the 12 mg BID dose in the OLE studies discontinue that dose. There have been no thrombotic events reported to date for the 8 mg BID dose and US FDA has not placed the 8 mg BID dose on hold. We are taking immediate steps to transition the patients in the OLE studies to the 8 mg BID dose arm in the ongoing studies," the company said.

"No thromboembolic events were observed during Phase-2 or Phase-3 trials, and we remain confident in deuruxolitinib’s potential to treat patients with Alopecia Areata and will work closely with the US FDA to address the agency’s concerns. US FDA is expected to state the concerns in a formal letter, expected within the next 30 days," it added.

Following the development, shares of Sun Pharma plunged 1.6% to hit an intra-day low of ₹970.55 apiece on the BSE. The scrip opened at ₹987.65 on Tuesday as against the closing price of the previous session of ₹986.80. The scrip closed at ₹972.45, down 1.45%. In contrast to this, the broader BSE Sensex closed at 61,354.71, up 0.40% or 242.27 points. During the session on Tuesday, the company’s market capitalisation stood at ₹2,33,317 crore, as 47,651 shares exchanged hands on the BSE against the two-week average of 0.51 lakh shares. At present, Sun Pharma’s share is trading 7.7% lower than the 52-week high of ₹1,071.90, whereas the shares are trading 25.17% higher than the 52-week low of ₹789.75.

In the December quarter of FY23, the pharmaceutical major’s net profit surged by 5% YoY to ₹2,166 crore. Its revenue surged 14% YoY to ₹11,241 crore as against ₹11,101 crore in the same period a year ago.

Sun Pharma in January said it'll acquire U.S.-based Concert Pharmaceuticals Inc. for $576 million to access the company's experimental drug for treating patchy baldness.

It had received a warning from the US FDA on possible violations of Current Good Manufacturing Practice (cGMP) regulations for its Halol facility in Gujarat in December last year.

US Food and Drug Administration (FDA)

US FDA halts Sun Pharma’s trial on dermatological drugs; stock down