Regulus rockets on positive mid-stage results for hepatitis C candidate RG-101

US microRNAs biotech firm Regulus Therapeutics (Nasdaq: RGLS) has announced positive interim results from one of the company's ongoing Phase II studies of RG-101 for the treatment of hepatitis C virus infection (HCV), with the news sending the company’s shares rocketing as much as 41.7% to $6.28 on Wednesday. The drug is under development with GlaxoSmithKline (LSE: GSK)

The study was designed to evaluate a shortened, four-week treatment regimen containing a subcutaneous administration of 2mg/kg of RG-101 at Day 1 and Day 29, in combination with four weeks of once/daily approved anti-viral agents Harvoni (ledipasvir and sofosbuvir, from Gilead), Olysio (simeprevir, from Janssen) or Daklinza (daclatasvir, from Bristol-Myers Squibb).  The study enrolled 79 treatment naïve genotype 1 and 4 HCV patients (Harvoni arm, n=27, Olysio arm, n=27, Daklinza arm, n=25).  38 patients have been evaluated through eight weeks of follow up. 97% of those patients (37/38) had HCV RNA viral load measurements below the limit of quantification.

To date, RG-101 has been generally well tolerated with the majority of adverse events considered mild or moderate, and with no study discontinuations.  For those patients through 12 weeks of follow-up, 100% remained below the limit of quantification (14/14). The primary endpoint analysis (12 week follow up) for all 79 patients in the study are anticipated to be reported in late second-quarter 2016.