Disappointing Results from Trial of Rituximab
in Primary Progressive MS
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Medical Update Memo
April 29, 2008
SUMMARY
Drug did not achieve primary goal of slowing
progression, sponsors still analyzing other
outcomes.
DETAILS
A study of intravenous rituximab (Rituxan®,
Genentech and Biogen Idec) in 439 people with
primary-progressive MS * has shown that the
drug did not slow disease progression when
compared with inactive placebo, the primary
endpoint of the study. These results have been
announced in a press release from Genentech
and Biogen Idec dated April 14, 2008. The companies
say that they will continue to analyze the
data and will present the results at an upcoming
medical meeting.
Background:
Rituximab binds to a molecule (CD20)
on the surface of B cells and depletes them
from the circulation for an average of 9
months. B cells are immune cells that make antibodies
and may play a role in the immune attack
on
brain and spinal cord tissues in multiple
sclerosis. Rituximab is approved for treating
some forms
of cancer. Researchers reported earlier this
year that in a small preliminary study, one
intravenous course of rituximab reduced disease
activity and relapses for 48 weeks in people
with relapsing-remitting MS (The New
England Journal of Medicine 2008
Feb 14;358[7]:676-88).
The current study evaluated the safety and
effectiveness of rituximab in people with
primary-progressive MS, a course of MS for which
no treatments
are currently on the market.
The Study:
The study enrolled 439 subjects
at 60 sites in the United States and Canada.
Participants were age 18-65 years, had primary-progressive
MS, and had had MS for at least one year.
Patients were randomly assigned to receive either
four
intravenous doses of Rituxan or inactive
placebo every six months for 96 weeks. MRI evaluations
were conducted before treatment, and at weeks
6, 48, 96 and 122. The primary outcome measured
was the time to confirmed disease progression.
Results:
Rituximab did not reduce the time
to disease progression, as compared with placebo.
In the press release, Hal Barron, MD, Genentech
senior vice president, development and chief
medical officer, notes, "There was some
evidence of biologic activity, and we will
continue to review all the data to better understand
the role of B cells in MS."
The safety data from the study are still being
analyzed as well. Serious adverse events occurred
more often (16.4%) in the rituximab arm than
in the placebo group (13.6%), with serious
infections occurring more often in the rituximab
group (4.5% vs. less than 1%) as well. There
were more infusion-related reactions with rituximab,
mostly mild to moderate in severity.
"This announcement is disappointing to
be sure," said
John R. Richert, MD, executive vice president
for research and clinical programs at the National
MS Society. "It highlights the urgent
need for more focused research to understand
and uncover therapeutic targets for the progressive
phases of MS and to develop better tools to
assess brain and spinal cord tissues to help
track the effectiveness of therapies. We're
grateful that Genentech and Biogen Idec conducted
this study in the underserved patient population
with primary-progressive MS."
*To read more
about primary progressive MS please see www.mssociety.ca/en/information/types.htm#prog_prime
Rituxan is a registered trademark of Genentech
and Biogen Idec
[With information
from the National MS Society (USA)]
ASK MS Information System Code: 1.2.1.12.2.g
National Client Services
Medical Information and Education
Disponible en français.
Disclaimer
The Multiple Sclerosis Society of Canada is an independent, voluntary health
agency and does not approve, endorse or recommend any specific product or therapy,
but provides information to assist individuals in making their own decisions.
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