(Yicai Global) May 31 -- Shares in Menovo Pharmaceutical slumped following a fire at a plant in the Chinese city of Hangzhou belonging to the maker of active  pharmaceutical ingredients used in Covid-19 treatments.

Menovo [SHA: 603538] closed down 5.8 percent at CNY40.16 (USD6.03), after plunging by the 10 percent daily trading limit at one point today. The firm’s stock price had already been sliding recently after catching the attention of investors earlier this year.

The fire broke out today at a transit workshop that held a lot of solvents, the Ningbo-based company told Yicai Global.

The plant, which sits in the Hangzhou Bay Shangyu Economic and Technological Development Zone, contributes 20 percent to 25 percent of Menovo’s revenue. It has been shut down temporarily because of the fire, an employee said, adding that the facility does not produce anti-Covid APIs.

Menovo announced in March that it had finished registration of its new plant to produce nirmatrelvir and key intermediates with an annual capacity of 60 tons. Nirmatrelvir is one of the major APIs in Pfizer’s oral Covid-19 medicine Paxlovid. China’s regulatory authorities approved imports of the drug in February.

Menovo’s stock price surged over 140 percent in March on the news, hitting a record high of CNY86.68 during trading on March 31. Their value has more than halved since then.

Local authorities started a rescue effort immediately after the fire broke out and no-one was hurt or trapped, the Hangzhou Bay General Management Office said in a statement, adding that the blaze was caused by organic solvents. An investigation is underway.

Formed in 2004, Menovo now has more than 2,500 employees. The firm reported a 129 percent jump in net profit to CNY115 million (USD17.3 million) in the first quarter from a year ago, on a 48 percent jump in revenue to CNY500 million.

Editors: Dou Shicong, Tom Litting