Local drugmaker Regulus Therapeutics Inc. watched its stock tank 42 percent Monday following unfavorable news from the U.S. Food and Drug Administration (FDA).

The La Jolla company reported the FDA would be continuing its hold on the clinical trial of Regulus’ lead drug candidate, RG-101.

The therapeutics company was in a Phase 1 study of RG-101 as a treatment for hepatitis C in patients with kidney failure. However, after a second patient who was enrolled in the clinical study developed a serious case of jaundice (a liver condition that causes yellowing of the eyes and skin), the trial was put on hold for safety reasons.

Regulus submitted a response to the FDA’s initial request for information late last year. The FDA has responded with a continuation of the clinical hold, and a request for additional expert review of the company’s safety data.

Regulus expects that data to be available at the end of 2017.

"While we are disappointed that the clinical hold was not lifted at this time, we plan to continue to work with the FDA to address their additional requests as we seek the removal of the clinical hold," said Dr. Timothy Wright, chief R&D officer of Regulus.

The local company’s stock (Nasdaq: RGLS) has fallen roughly 77 percent over the last 12 months, and ended the day Monday at $1.30 per share. Regulus’ market cap sits at nearly $69 million.