We have been using interferon and glatiramer for the
last 15 years for treatment of MS. In the studies of the effectiveness of each drug, they reduced the number of relapses
by about 30% compared with placebo. Direct comparisons of high dose interferon (Betaseron, Rebif) with low dose interferon
(Avonex) have shown the higher doses are more effective. Until now, there have not been any well done comparisons of
the relative effectiveness of interferon and glatiramer. Now preliminary results from two studies, one comparing
Rebif and Copaxone and the other comparing Betaseron and Copaxone, have been reported.
study: These results were reported at the ECTRIMS meeting in October 2007. This was a large
clinical study comparing the effectiveness of Rebif, an interferon, with Copaxone, glatiramer acetate. The trial was
funded by EMD Serono, the makers of Rebif. There were 386 people on Rebif and 378 on Copaxone followed for 96 weeks.
The main outcome measure was the time to first relapse. They did not find any difference between the two treatments,
but the number of relapses observed was less than expected. The number of patients who completed the study was similar
in both groups. The MRI measures favored Rebif, which is expected since interferon has a larger effect on MRI activity
than glatiramer does.
BEYOND study: This study has only been reported
as a press release on the Bayer website, so the data available are limited. This study compared Betaseron, double-dose
Betaseron, and Copaxone in 2,244 patients. The main outcome measure was the risk for relapse, and there was no difference
between the three groups. The number of people completing the study was similar in each group. MRI results are
not reported yet.
Conclusions: There is not a significant difference
in the effectiveness of interferon and glatiramer in their ability to prevent relapses. There also does not appear to
be much difference in the tolerability of the two treatments. The side effects are quite different, but the number of
people staying on therapy is similar. Either interferon or glatiramer is a good choice for relapsing-remitting
MS, and there is no reason to prefer one over the other based on effectiveness or tolerability. The currently marketed
dose of Betaseron is sufficient to get the maximum benefit.
We should have more detailed information from both
of these studies in the next few months.