Corixa Reports Positive Preliminary Results for Its Phase III Pivotal Trial of RC-529 Synthetic Adjuvant for Use In Preventing Hepatitis B Infection
Primary and Secondary Efficacy Endpoints Met with High Degrees of Statistical Significance
SEATTLE and The Netherlands--(BUSINESS WIRE)--Jan. 8, 2002--Corixa Corporation (Nasdaq:CRXA - news), a developer of immunotherapeutics, and Rhein Biotech, N.V. (Neuer Markt, RBO 919544), a developer, producer and marketer of vaccines, today announced highly statistically significant preliminary results of an ongoing Phase III, randomized, controlled pivotal trial to test the efficacy and safety of Corixa's RC-529 synthetic adjuvant when used in combination with Rhein Biotech's yeast Hansenula polymorpha based recombinant Hepatitis B antigen (HBsAg), the active ingredient of commercially approved Hepatitis B vaccines (Hepavax-Gene®, AgB®, Biovac B®).
Results of the primary efficacy analyses showed that there were significantly more patients seroprotected after two immunizations with Rhein Biotech's Hepatitis B vaccine plus RC-529 than with the Hepatitis B vaccine alone (95.5 percent vs. 82.1 percent, p=0.001). Preliminary results were presented today by Corixa and Rhein Biotech at the World Health Organization's ``Third Meeting on Novel Adjuvants Currently In/Close to Human Clinical Testing'' in Annecy, France. Safety data will not be available until the completion of the study.
Trial Design
The study was designed to compare the efficacy and safety of vaccination with the Hepatitis B vaccine plus Corixa's RC-529 adjuvant to vaccination with the Hepatitis B vaccine alone in healthy adults who were not immune to Hepatitis B virus (HBV). Healthy adults were randomized to one of two treatment arms and will have received three intramuscular injections of either the Hepatitis B vaccine plus RC-529 or the Hepatitis B vaccine alone on days 0, 30 and 180. The primary objective was to evaluate the number of patients who were seroprotected at day 90 following two vaccinations with the Hepatitis B vaccine plus RC-529 compared to the Hepatitis B vaccine alone. Secondary efficacy endpoints were: the number (percentage) of patients achieving seroprotection at days 30, 60, 90, 180 and 210; the number (percentage) of patients achieving seroconversion (defined as an anti-HbsAg titer of greater than or equal to 1 MIU/mL) at day 30, 60, 90, 180 or 210; and the anti-HbsAg titer (antibody levels) at days 30, 60, 90, 180 and 210.
Efficacy Analysis
A total of 285 patients received at least one vaccination. A total of 272 of these patients were evaluated for efficacy - 132 patients in the Hepatitis B vaccine plus RC-529 group and 140 patients in the Hepatitis B vaccine alone group. In the Hepatitis B vaccine plus RC-529 group, 126 of 132 (95.5 percent) of the patients achieved seroprotection by day 90, compared to 115 of 140 (82.1 percent) of the patients in the the Hepatitis B vaccine alone group. The difference in percentage of patients achieving seroprotection was statistically significant (p=0.001).
Moreover, 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) showed a statistically significant benefit in favor of vaccination with the Hepatitis B vaccine plus RC-529 as opposed to vaccination with the Hepatitis B vaccine alone. Historically, it is important to note that higher antibody titers have been found to correlate with a longer duration of protection. Final analysis of all other secondary endpoint values (days 180 and 210) cannot be completed until these remaining visits have occured.
``We are extremely pleased with the results of this trial,'' stated Steven Gillis, Ph.D., chairman and chief executive officer of Corixa. ``We hope the data obtained will prove useful for further commercial development of RC-529 with Rhein Biotech and other vaccine partners and provide further evidence of the potential value of our proprietary adjuvant portfolio. RC-529 is one of several immunostimulatory aminoalkyl glucosaminide phosphate derivatives currently being tested in clinical settings. We are encouraged by these initial results particularly as they are derived from a randomized, blinded and controlled clinical trial.''
``The results of the study confirm our expectations of being able to reduce the amount of injections needed for full protection against Hepatitis B infection from three doses to two,'' stated Dr. Zbigniew Janowicz, vice president R&D of Rhein Biotech. ``This improved vaccine will be very important for vaccination of travelers, healthcare professionals, patients undergoing surgery, and other people who need fast protection against Hepatitis B. The two-dose Hepatitis B vaccine is also interesting for alternative vaccination programs of children and adolescents, as currently evaluated by various national vaccination authorities. Furthermore, we are pleased about the successful scientific cooperation with our partner, Corixa, and are looking forward to the continuation of the collaboration.''
About Hepatitis B and HBV Vaccines
Commercial vaccines based on Hepatitis B surface antigen (HBsAg) are currently available that are safe and effective in prophylactic reduction of the incidence of HBV infection. Generally those vaccines are given in a three-dose regime. Using synthetic chemistry techniques, Corixa has developed RC-529, an aminoalkyl glucosaminide 4-phosphate molecule which, when added to certain vaccines, has been shown in preclinical experiments to enhance the specific immune response to the vaccine antigen. In these experiments, the addition of RC-529 to AgB resulted in higher anti-Hepatitis B antibody responses in mice and rabbits as compared to vaccination with AgB alone.
Hepatitis B is a disease caused by the Hepatitis B virus present in the blood and body fluids of an infected individual. HBV infection can cause acute illness, and in some people, may develop into a chronic infection. Chronic HBV infection may lead to serious problems including chronic liver disease, cirrhosis, hepatocellular carcinoma, and death. According to the World Health Organization, of the 2 billion people who have been infected with the Hepatitis B virus, more than 350 million have chronic (lifelong) infections. These chronically infected persons are at high risk of death from cirrhosis of the liver and liver cancer, diseases that kill about one million persons each year (Fact Sheet World Health Organization/204, October 2000).
About Corixa
Corixa is a developer of immunotherapeutics with a commitment to treating and preventing autoimmune diseases, cancer and infectious diseases by understanding and directing the immune system. Corixa is focused on immunotherapeutic products and has a broad technology platform enabling both fully integrated vaccine design and the use of its separate, proprietary product components on a stand-alone basis. Corixa currently has 16 programs in clinical development and 22 programs in preclinical development, including its most advanced product candidate, Bexxar®, a monoclonal antibody conjugated to a radioisotope.
The company partners with numerous developers and marketers of pharmaceuticals, targeting products that are Powered by Corixa(TM) technology with the goal of making its potential products available to patients around the world. Corixa was founded in 1994 and is headquartered in Seattle, Washington, with additional operations in Hamilton, Montana and South San Francisco, California. For more information, please visit Corixa's Website at www.corixa.com or call the company's investor relations information line at 1.877.4CORIXA or 877/426-7492.
About Rhein
Rhein Biotech is a global biotechnology group, which develops, produces and markets vaccines and therapeutic compounds based on its platform technologies. With Hepavax-Gene®, manufactured by subsidiary GreenCross Vaccine, the Group has advanced to the world's third largest producer of Hepatitis B vaccine. Rhein Biotech currently markets 13 products reaching 75 percent of the world's population. The Group employs over 300 people, with one third in R&D. Rhein Biotech has been listed on the Neuer Markt (Frankfurt) since April 1999 and has been included in the Nemax 50 index as of December 2001. For more information on Rhein Biotech, visit www.rheinbiotech.com.
Forward Looking Statements
Except for the historical information presented, certain matters discussed in this press release are forward-looking statements. Forward-looking statements are based on the opinions and estimates of management at the time the statements are made. They are subject to certain risks and uncertainties that could cause actual results to differ materially from any future results, performance or achievements expressed or implied by such statements. Factors that could affect Corixa's actual results include, but are not limited to, the ``Factors Affecting Our Operating Results, Our Business and Our Stock Price,'' described in Corixa's Quarterly Report on Form 10-Q for the quarter ended September 30, 2001, copies of which are available from Corixa's investor relations department. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this release.
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Contact:
Corixa Corporation
Jim DeNike, 206/754-5716
denike@corixa.com
or
FitzGerald Communications
Jen Reinhard, 415/986-9500
jreinhard@fitzgerald.com |
