Acorda Therapeutics Inc. reported that post-marketing study
results for Ampyra (Fampyra in Canada) have failed to show an
improvement in the walking speed of people with MS in the United
States.
Following approval of Ampyra 10 mg in 2010, the FDA requested
that Acorda conduct a clinical trial to assess the safety and
efficacy of a lower dose, 5mg taken twice daily as compared with
the approved 10 mg dose twice daily, and placebo. Both the 5 mg
and 10 mg treatment groups failed to show improvement in walking
speed when compared with placebo. When investigators analyzed the
data using methods similar to the previous studies, the 10-mg
dose significantly improved walking speed compared with placebo
in responders, but the 5-mg dose did not. In addition there were
significantly more responders (average improvement in walking
speed of at least 20% from baseline) in the 10-mg group compared
to the placebo group.
Acorda reported that two trial participants, each from the 5 mg
and 10 mg treatment group, experienced serious adverse events,
including the loss of consciousness in the 10 mg group. This
follows the recent safety warning issued in July by the FDA about the increased risk of
seizures from the drug in people with kidney impairment in July.
What do these findings mean for Canadians currently being
treated with Fampyra?
At this point, Health Canada has not made a formal statement
related to these findings and it is not clear what the FDA plans
on doing with this new data. It is possible that the most recent
findings will be included in the product information (monograph)
for physicians to prescribe appropriately.
Health Canada approved fampridine, (PrFAMPYRA™) on
February 10, 2012 for the symptomatic improvement of walking in
adults with multiple sclerosis (MS) with walking disability.
Health Canada labeling for Fampyra currently recommends assessing
kidney function prior to treatment as well as ongoing monitoring
during treatment. Individuals who miss a dose are advised not to
take an additional dose of Ampyra as it may increase the risk of
seizures. Individuals are strongly advised to follow the
prescribing instructions for taking FAMPYRA and to report any
worrying side-effects to their doctor immediately.