ArQule (NASDAQ:ARQL) stock fell 23 percent on Wednesday on safety concerns about its drug candidate tivantinib.
Wednesday, shares were trading at $5.15, down 9 per cent from the start of the year.
Tivantinib is a treatment for lung cancer.
In a federal filing Tuesday, ArQule said that its Japanese development partner, Kyowa Hakko Kirin Co., has temporarily suspended a Phase III clinical trial testing tivantinib in combination with the lung-cancer therapy Tarceva over concerns that some of the patients had developed interstitial lung disease.
"During review of the additional information, treatment of patients already enrolled in the study is continuing pursuant to the protocol for the study. Updates on the status of this review and a determination regarding whether to restart patient enrollment will be provided as warranted," ArQule said in the filing.