Elan up on positive Tsyabri data

Two-year data from a phase III monotherapy trial, named AFFIRM, showed that treatment with Tsyabri (natalizumab) led to a significant reduction in disability progression, the rate of clinical relapses and brain lesions in patients with relapsing forms of multiple sclerosis (MS).

AFFIRM met all primary and secondary endpoints, including disability progression and relapse rate and Tsyabri treatment was also associated with a low level of immunogenicity.

Tsyabri treatment led to a 42% reduction in the risk of disability progression compared to placebo. Tsyabri also reduced the rate of clinical relapses by 67% compared to placebo, which was sustained and consistent with the previously reported one-year results.

On February 28, 2005, Biogen Idec and Elan announced that they voluntarily suspended Tsyabri from the US market and all ongoing clinical trials. This decision was based on reports of progressive multifocal leukoencephalopathy (PML), a rare and frequently fatal, demyelinating disease of the central nervous system. A safety evaluation concerning Tsyabri and any possible link to PML is ongoing and the results of this evaluation will be discussed with regulatory agencies to determine possible re-initiation of dosing in clinical trials and future commercial availability.

“While an evaluation is underway to better understand recent developments with Tsyabri, these data confirm the efficacy of Tsyabri on clinical relapse and define its impact on disability progression,” said Dr Chris Polman, lead investigator of the AFFIRM study, professor of neurology at Free University Medical Centre, and clinical and scientific director of the Multiple Sclerosis Centre at the VU Medical Centre, Amsterdam. “The efficacy of Tsyabri underscores its importance for MS patients.”