RG-101 Targeting miR-122 for HCV

Hepatitis C is a result of a hepatocyte specific infection induced by the virus known as HCV. Chronic HCV may lead to significant liver disease, including chronic active hepatitis, cirrhosis, and hepatocellular carcinoma. According to the World Health Organization, up to 170 million people are chronically infected with HCV worldwide, and more than 350,000 people die from HCV annually. The CDC estimates that there are currently approximately 3.2 million persons infected with HCV in the United States.  Regulus believes that its’ miR-122 antagonist, RG-101, may be a useful agent in emerging combination regimens to address difficult-to-treat genotypes and to potentially expand upon the current therapies available to clinicians treating HCV patients.

RG-101 is Regulus’ wholly-owned, GalNAc-conjugated anti-miR targeting miR-122 for the treatment of HCV.  In a completed Phase I clinical study, Regulus demonstrated that treatment with a single subcutaneous dose of either 2 mg/kg or 4 mg/kg of RG-101 as monotherapy resulted in significant and sustained viral load reductions in all treated HCV patients, including patients with difficult to treat genotypes, various liver fibrosis status and those who have experienced viral relapse after a prior IFN-containing regimen.  To date, RG-101 has a favorable safety profile with no serious adverse events or discontinuations reported in the treated HCV patients.

Regulus’ Phase II program and development strategy for RG-101 includes evaluating RG-101 (1) in combination studies with different approved direct-acting anti-HCV agents (DAAs); (2) in combination with an investigational oral DAA that can be formulated into a Long Acting Parenteral formulation for injection (LAP) providing the potential for a single-visit therapy; and (3) in certain underserved HCV patient populations.

  1. Enrollment is complete in an ongoing Phase II study evaluating the combination of RG-101 with multiple approved DAAs. Treatment-naïve patients chronically infected with genotypes 1 or 4 were randomized to one of three treatment arms (n=78).  Patients receive a single subcutaneous injection of 2 mg/kg of RG-101, followed by 28 days of once/daily DAAs Harvoni®, Olysio®, or Daklinza®, followed by an additional subcutaneous injection of 2 mg/kg of RG-101 on Day 29.  Regulus is planning to report interim results from this study in mid-February 2016 and primary endpoint results for sustained viral response data 12 weeks following conclusion of treatment (SVR12) are anticipated to be disclosed late in Q2 2016.
  2. In early November, Regulus announced that the company entered into a clinical trial collaboration agreement with GlaxoSmithKline (“GSK”) to evaluate an HCV combination regimen. In March 2016, Regulus plans to initiate a multi-center, open-label Phase II study evaluating the combination of a single subcutaneous injection of 4 mg/kg of RG-101 and daily oral administrations of 20 mg of GSK2878175, an investigational non-nucleoside NS5B polymerase inhibitor, for up to 12 weeks in treatment-naïve patients chronically infected with HCV genotypes 1 and 3. Concurrently, GSK will work on developing a “LAP” formulation of GSK2878175 as a single intra-muscular injection, providing the potential for a single-visit therapeutic treatment for HCV that could improve patient compliance through reduced dosing intervals and potentially extend opportunities for HCV therapeutic intervention.  This LAP formulation of GSK2878175 may be used in additional clinical trials together with RG-101 following completion of the planned Phase II study, although any additional studies are not covered by the current collaboration agreement. Regulus expects to report safety and efficacy data from the GSK Phase II study before the end of 2016.
  3. In addition to the combination studies, Regulus has commenced enrolling patients in a multi-center, open label, non-randomized Phase I study to compare the safety, tolerability, pharmacokinetics, and pharmacodynamics of 2 mg/kg of RG-101 in subjects with severe renal insufficiency or end-stage renal disease (ESRD) to healthy control subjects, and further explore RG-101 in hepatitis C infected subjects with severe renal insufficiency or ESRD.  The Phase I study is designed to have three treatment arms (n=24): (i) healthy volunteers (n=8); (ii) patients with severe renal impairment or ESRD (n=8); and (iii) HCV patients with severe renal impairment or ESRD (n=8).  Enrollment is expected to be complete in the first half of 2016 with efficacy data from the HCV/severe renal impairment or ESRD arm anticipated in the second half of 2016.