PR Newswire, Friday, January 10, 1997 at 09:54
Clinical Data Published in New England Journal of Medicine by SmithKline
Beecham and Walter Reed Army Institute of Research
HAMILTON, Mont., Jan. 10 /PRNewswire/ -- The use of MPL immunostimulant as
an adjuvant component is critical to the efficacy of an experimental malaria
vaccine, according to human clinical data published this week in The New
England Journal of Medicine by SmithKline Beecham Biologicals (SB Bio) and
Walter Reed Army Institute of Research (WRAIR).
MPL immunostimulant is a product of Ribi ImmunoChem Research, Inc.
(Nasdaq: RIBI) and has been licensed to SmithKline Beecham (NYSE: SBH) for use
in the development and potential commercialization of vaccines for malaria and
other diseases. SB Bio is the vaccine-development subsidiary of SmithKline
Beecham.
According to the published data, three doses of an experimental malaria
vaccine incorporating MPL immunostimulant in addition to another adjuvant
component known as QS21 protected six of seven volunteers against a challenge
infection, for an efficacy rate of 86%. The challenge was by bites by
mosquitoes infected with the malaria-causing organism. The data showed that
the formulation incorporating MPL stimulated the highest levels of antibodies
to an important malaria antigen. The researchers noted further that this
formulation probably stimulated an unidentified cellular immune mechanism
because another formulation excluding MPL that achieved similar antibody
levels protected only two of seven volunteers against the challenge infection.
An associated editorial in the same issue of The New England Journal of
Medicine stated that "these results represent a considerable advance in the
development of malaria vaccines" and also noted that "the design of this trial
showed the important role of these immune potentiators in inducing protection.
The striking effect of certain adjuvants on the efficacy of immunization is
noteworthy and likely to be applicable to other microbial sub-unit vaccines."
In a related announcement, SB said that a series of further clinical
studies, including a limited field trial in West Africa, using the formulation
incorporating MPL will be initiated in the next few months to determine
duration of immunity and other aspects of the immune mechanisms involved.
Malaria, which is caused primarily by the parasite Plasmodium falciparum,
occurs in more than 90 countries, results in up to 500 million clinical cases
annually and causes more than 2 million deaths annually. With rare exceptions,
it is transmitted via mosquito bites, and no preventive vaccine is now
available. Development of multi-drug resistance by the organisms that cause
malaria has led to considerably higher treatment costs, accentuating the need
for a preventive vaccine.
"The data generated by SB Bio and WRAIR is most interesting since it may
point the way to an effective malaria vaccine. The combination of QS21 and MPL
as the adjuvant system once again establishes Ribi adjuvants (MPL) as the
cornerstone of many adjuvant systems," said Robert E. Ivy, Chief Executive
Officer, President and Chairman of Ribi ImmunoChem.
Ribi ImmunoChem Research, Inc., a biopharmaceutical company founded in
1981, is engaged in the development of immunostimulants for use in preventing
and treating human disease.
Ribi ImmunoChem news releases are now available via the Internet at PR
Newswire's Company News on Call: prnewswire.com.
SOURCE Ribi ImmunoChem Research Inc.
-0- 01/10/97
/CONTACT: Jeffrey S. McDowell, Corporate Information Manager of Ribi
ImmunoChem Research, Inc., 406-363-6214, ext. 153/
/Ribi ImmunoChem Research Inc. press releases available through Company
News On-Call by fax, 800-758-5804, ext. 752250, or at
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