Regulus Therapeutics Inc. (NASDAQ: RGLS)’s hepatitis C (HCV) drug candidate has been put on clinical hold by the FDA. The company received a verbal notice from the agency regarding the clinical hold affecting its lead drug candidate RG-101 and will be issued with a written notice within 30 days. What triggered the FDA’s clinical hold notice on RG-101 and what does it mean concerning the future of the drug candidate?
The FDA issued the clinical hold on RG-101 after Regulus Therapeutics Inc. (NASDAQ: RGLS) reported a second serious adverse event (SAE) regarding the medicine. The SAE related to occurrence of jaundice in a patient who had taken the drug. The side effect was observed on the patient 117 days after receiving the treatment. The patient who exhibited jaundice had been on dialysis because of end-stage renal disease.
It is worth pointing out that RGLS is trying to focus RG-101 as a treatment for HCV in a subset of patients who are also suffering from end-stage renal disease. The reason for that is that people afflicted by end-stage renal disease don’t respond well to standard treatments for HCV that are already available on the market.
But Regulus Therapeutics Inc. (NASDAQ: RGLS)’s efforts to target HCV area with unmet medical need are encountering hurdles.
Where clinical hold leave RGLS?
The FDA’s clinical hold doesn’t mean the end of the road for Regulus Therapeutics Inc. (NASDAQ: RGLS) and its lead candidate RG-101. The company will continue with the three clinical studies of the drug that have already enrolled subjects. However, the clinical hold affects future studies of the compound. As such, the company must move quickly to see that the FDA releases the clinical hold to allow it to continue with the development of RG-101 without restrictions.
Side effects of a treatment
It has not yet been settled that it was Regulus Therapeutics Inc. (NASDAQ: RGLS)’s RG-101 that caused jaundice in the patient. But FDA doesn’t take chances and that explains the notice of clinical hold on the drug. Perhaps the agency may release the hold after it verifies that RG-101 was not responsible for the adverse side effect. However, in a worst case scenario, the FDA could halt all the clinical programs of RG-101, thus sending RGLS back to the drawing board. That explains the caution investors are exhibiting regarding the stock following the clinical hold notice.