Intercell and Romark Laboratories are teaming up to evaluate a combination of their respective HCV vaccine IC41 and antiviral drug nitazoxanide, in clinical trials against chronic HCV genotype-1. A European Phase II clinical trial is scheduled to start during the first half of 2011. It will include some 60 treatment-naive patients and compare treatment using either IC41 plus nitazoxanide, or treatment using IC41 plus nitazoxanide and Pegasys® (peginterferon), with the current standard of care regimen, which comprises Pegasys and Copegus® (ribavirin).
Intercell’s IC41 therapeutic HCV vaccine candidate combines five synthetic T-cell-stimulating peptides and the firm’s poly-arginine adjuvant IC30. The candidate has already undergone Phase II trials in treatment-naïve HCV genotype-1 patients. Trial data found that an optimized vaccination schedule resulted in viral load reductions of over 75% in patients with high baseline RNA levels. The reduction was sustained for at least six months after treatment ended.
The firm’s prophylactic vaccine against Japanese encephalitis has already been approved in major markets including the U.S., Europe, Canada, Australia, and most recently Switzerland. Its in-house and partnered clinical pipeline includes a Phase III-stage prophylactic vaccine patch against traveller’s diarrhea and a prophylactic vaccine against S. aureus , which is also undergoing Phase III studies. The Phase II pipeline includes prophylactic vaccines against Pseudomonas, and a prophylactic vaccine patch targeting pandemic influenza. Vaccines against seasonal influenza, tuberculosis, and pneumococcus are in Phase I development. Intercell is separately developing a preclinical pipeline of vaccine and antibody candidates against pathogens including Group A and B Streptococcus, Lyme Borreliosis, Staphylococcus. Aureus, and pneumococcus.
Nitazoxanide is the first of a new class of broad-spectrum thiazolide antiviral agents, Romark claims. The drug has been available commercially for over 10 years as a treatment, trademarked Alinia™, for diarrhea caused by Cryptosporidium and Giardia.
In May the firm reported final results from a U.S.-based Phase II trial evaluating nitazoxanide in 112 treatment-naïve patients with genotype 1 chronic hepatitis C, 35% of these patients had advanced stage 3 or 4 fibrosis. Patients were randomized to receive either nitazoxanide (500 mg twice daily) plus peginterferon alfa-2a and Copegus, or placebo plus Pegasys and Copegus. The results showed that a sustained virologic response (undetectable HCV RNA 24 weeks after the end of treatment) was achieved in 44% of patients treated with nitazoxanide plus standard therapy for 48 weeks, and 32% of patients treated with placebo plus standard therapy. SVR rates were consistently higher in subsets of patients with high baseline viral load (41% vs. 29%) and in African Americans (38% vs. 20%).
At the time the data was released, Romark stated plans to start Phase III trials of a controlled-release tablet formulation of nitazoxanide in combination with peginterferon, with or without ribavirin, later in 2010. Phase II evaluation of the controlled release tablets in genotype 1 and 4 patients are under way.
The U.S. AIDS Clinical Trials Group is separately studying nitazoxanide plus peginterferon and ribavirin for treating chronic hepatitis C in patients co-infected with HIV.