- The Food and Drug Administration placed a clinical hold on Regulus Therapeutics' chronic hepatitis C drug after a second serious adverse event of jaundice was reported related to Phase 1 testing, the company said Monday.
- A hepatitis C patient with end-stage renal disease, who was enrolled in Regulus' ongoing study, developed jaundice around 4 months after receiving one dose of the drug.
- Shares of Regulus dropped by nearly half in pre-market trading Tuesday morning. The drug, known as RG-101, is Regulus' lead candidate. The company had just secured a $30 million loan to support further development, which will now be halted.
Regulus said the timeline for its other three ongoing studies of RG-101 would not impacted since all patients have already completed dosing.
The FDA verbally told the company that RG-101 would be placed ina clinical hold but Regulus expects to receive a formal letter for the regulator with 30 days.
Regulus has developed RG-101 to block a type of micro-RNA known as miR-122, which is used by the hepatitis C virus to replicate. Clinical trials have tested the injectable drug in combination with already approved anti-virals for the disease, such as Gilead's Harvoni or Bristol-Myers Squibb's Daklinza.
The company believes combining RG-101 with current drugs could shorten the treatment regimens to four weeks or less and help target difficult-to-treat genotypes.
But the high efficacy and ease of administration for the oral anti-virals may limit the potential for RG-101, if Regulus overcomes the current side-effect concerns.
The company said it would work with the FDA to resolve the clinical hold and plans to deliver results from its other RG-101 studies as planned.