Drug & Device Development

Peptide vaccine shows some promise in hard-to-treat HCV

Last Updated: 2008-06-30 15:20:51 -0400 (Reuters Health)

NEW YORK (Reuters Health) - The synthetic peptide vaccine IC41 induces a T-cell response specific to hepatitis C virus (HCV) in patients with chronic HCV infection refractory to standard therapy, German researchers report.

"This clinical study with the HCV therapeutic vaccine IC41clearly shows that a T lymphocyte immune response can be induced in the difficult-to-treat non-responders to previous interferon-based HCV therapies," lead investigator Dr. Michael P. Manns told Reuters Health.

In the May issue of Gastroenterology, Dr. Manns of Hannover Medical School and colleagues note that in an earlier study with healthy volunteers the vaccine was shown to be safe and capable of eliciting HCV-specific immune response.

In the current trial, the team studied 60 patients with chronic HCV infection who were not responding or were relapsing on standard therapy. The patients were randomized into five groups. Three groups received one of three doses of a total of six IC41 vaccinations; a fourth group received HCV peptides alone (control group); and a fifth group received the poly-L-arginine adjuvant alone (control group).

The researchers detected T-cell proliferation in 67% of patients who received the vaccine compared with 17% in those who received the HCV peptides alone. No response was seen in patients who received the adjuvant alone.

Three patients had a plasma HCV RNA response; all were in one of the two highest dose vaccine groups. These patients had a greater than 1 log decline in HCV RNA. However, this was transient and was followed by a rebound to baseline levels.

Nevertheless, concluded Dr. Manns, "although the decrease in viral load is minor, the stimulation of the cellular immune response against important HCV T lymphocytes is encouraging."

In an accompanying editorial, Dr. Carlo Ferrari of Azienda Ospedaliero-Universitaria di Parma, Italy, observes: "Although definitive answers are still lacking, what is promising for immunotherapy is that our knowledge of the complex mechanisms governing T-cell differentiation and influencing T-cell dysfunction in chronic hepatitis C are rapidly improving."

Gastroenterology 2008;134:1385-1395,1601-1614.