Teva Pharmaceutical (Nasdaq: TEVA) is doing everything it can to get multiple sclerosis (MS) patients onto its MS treatment, Copaxone. In December it released data showing that the drug helped patients early in their MS progression. Yesterday it published data supporting Copaxone's use in patients that failed their first therapy.

The data showed that patients who switched after failing treatment on an interferon beta -- such as Biogen Idec's (Nasdaq: BIIB) Avonex or EMD Serono's and Pfizer's (NYSE: PFE) Rebif -- to Copaxone showed a 77% reduction in the per-year relapse rate. Perhaps more importantly, the fraction of patients not experiencing any relapses during the three-year study period jumped from 16% before to 68% following the switch. In contrast, the fraction of relapse-free patients who merely switched from one interferon beta to another remained similar before and after that switch.

Teva is pushing its data hard, because relative newcomer Tysabri -- from Biogen and Elan (NYSE: ELN) -- is doing well. It's not approved as a front-line treatment, so it won't take all of Teva's patients, but Teva and its marketing partner Sanofi-Aventis (NYSE: SNY) would clearly like to get a shot at patients coming off interferon beta treatments before Biogen and Elan can.

Last year Copaxone's global sales increased 21% year over year, so it looks like Teva is doing a pretty good job selling the drug. Hopefully, as Biogen and Elan continue to push toward their own goal of 100,000 patients using Tysabri by the end of 2010, Teva will continue to push back. Yesterday's data won't hurt.

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Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. Biogen is a pick of the Stock Advisor newsletter. Pfizer is a pick of both the Income Investor and Inside Value newsletters. The Fool has a disclosure policy.