BioWorld International Correspondent
Rhein Biotech NV and Corixa Corp. reported positive preliminary data from a Phase III trial of their two-dose hepatitis B vaccine.
Marcel Jacobs, spokesman for Maastricht, the Netherlands-based Rhein Biotech, said the final analysis of the data should be completed this quarter, when the safety data also will become available.
“We expect to file the registration by the end of this year,” he told BioWorld International.
The company plans to register and market the product initially in Argentina, where it performed the Phase III studies. The product is based on a combination of Rhein Biotech’s Hansenula polymorpha yeast-based recombinant hepatitis B antigen, which is the active ingredient in several commercially approved HBV vaccines, and Seattle-based Corixa’s synthetic adjuvant RC-529, an immunostimulatory derivative of aminoalkyl glucosaminide phosphate.
Two hundred and seventy-two of the 285 subjects enrolled in the study were evaluated for efficacy. Of these, 132 were administered hepatitis B vaccine plus RC-529 at days 0, 30 and 180, while 140 subjects received the vaccine alone at the same intervals. In the former group, 126 of the 132 trial participants (95.5 percent) attained seroprotection at day 90, whereas 115 of the 140 in the latter group (82.1 percent) achieved seroprotection in the same time frame. The difference was statistically significant.
Analysis of secondary efficacy endpoints (seroprotection at days 30 and 60, seroconversion rates at days 30 and 60, and antibody titer levels at days 30, 60 and 90) also demonstrated a statistically significant benefit in favor of vaccination with the vaccine plus RC-529, Rhein Biotech said.
“The main advantage of the vaccine is faster protection,” Jacobs said. The two-dose version of the vaccine cuts the total time required for immunization from six months to one month. But Rhein Biotech does not plan to replace its existing three-dose offering with the two-dose alternative. Instead, it is positioning the latter product as a niche offering for those who need vaccination quickly, such as travelers, health care professionals and surgical patients.
The company sold 150 million doses of its existing three-dose product last year, Jacobs said, in non-Western markets. This product is now the subject of a collaboration with Chiron Corp., of Emeryville, Calif., to develop a combination vaccine against diphtheria, tetanus, pertussis, hepatitis B and Haemophilus influenza B. The program is still in the preclinical stage, but the partners expect to launch a product in 2005, Jacobs said.
Rhein Biotech also disclosed a new research agreement last week, with Epimmune Inc., of San Diego. Terms were not disclosed, but Rhein Biotech plans to evaluate Epimmune’s PADRE T-cell activation technology. “As soon as we get some interesting results we would like to go into a commercial agreement with Epimmune,” Jacobs said.