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Mixed Results Announced for Fampridine-SR Trials
"The MS study data further confirm results from two previous Phase 2 trials of Fampridine-SR's potential to benefit people with MS. We are excited by this result and are looking forward to discussing next steps with the FDA. While we are disappointed in the overall outcome of the SCI trials, they did provide further evidence of potential benefit in this indication, consistent with data from our previous studies. Acorda will continue to investigate the use of Fampridine-SR for spinal cord injury," said Ron Cohen, M.D., Acorda's President and Chief Executive Officer.
The MS trial showed a strong positive trend compared to placebo in its primary endpoint, improvement in walking speed, as measured by a timed 25-foot walk. The trial also showed a statistically significant improvement across dose groups in its secondary endpoint, the Lower Extremity Manual Muscle Test (LEMMT). These data are consistent with data from earlier double-blind trials that involved fewer subjects and shorter treatment periods. Because most people with MS experience both impairment in walking ability and weakened muscles, the Timed 25 Foot Walk is widely used to assess MS patients' functional status. The LEMMT is a standardized, 5-point manual assessment of strength, applied to leg muscle groups. Analysis of the other secondary endpoints in the trial is ongoing.
Andrew Goodman, M.D., Director of the MS Center at the University of Rochester Medical School and chair of the company's MS advisory group, said, "We are encouraged by the findings of this Phase 2 trial of Fampridine-SR in MS because impaired walking and muscle weakness are two of the most common and devastating aspects of this disease. There is a tremendous unmet need for treatments that can improve walking and weakness, as none of the currently available therapies can do so."
The two SCI trials did not reach statistical significance in their primary endpoints, reduction of spasticity as measured by the Ashworth score and improvement of patients' Subject Global Impression (SGI) rating. The Ashworth is a validated, 5-point clinician assessment of an individual's spasticity (the involuntary tension, stiffness or contraction of muscles.) The SGI is a seven-point scale in which study participants rate how they feel about the overall effect of the study drug. In one of the SCI studies, the data showed a positive trend (p=0.069) toward improvement on the Ashworth score when analyzed across all observations during the double-blind study drug period, the study's pre-specified plan of analysis. When analyzed based on the subjects' last observation carried forward (LOCF), a commonly used method of analysis, the Ashworth score in that study was statistically significant (p=0.006). The drug groups in both studies showed a progressive mean improvement on the Ashworth score during the double-blind study drug period. However, the placebo group in one of the studies showed a more pronounced reduction than expected. Analysis of the trials' secondary endpoints of improvement in bowel, bladder or sexual function is ongoing.
In both the SCI and MS studies, the adverse event profile, including serious adverse events, was consistent with that observed in previous studies. The most common adverse events were insomnia, paresthesias, dizziness and nausea, the majority of which were rated as mild to moderate.
Fampridine is a selective neuronal potassium channel blocker and has been shown to restore nerve conduction by blocking the exposed potassium channels in damaged nerve fibers that have lost their insulating sheath of myelin. By closing the channels, fampridine allows such nerve fibers to transmit impulses again. Fampridine-SR is an oral, sustained-release formulation of fampridine, designed for twice-daily dosing.
In addition to Fampridine-SR, Acorda's clinical-stage pipeline includes valrocemide, which it is developing with Teva Pharmaceutical Industries Ltd. for the treatment of epilepsy and bipolar disorder. The company's pre-clinical stage pipeline includes therapeutic candidates for remyelination and nerve repair in SCI, MS and other CNS conditions, and the Company is continuing to evaluate in-licensing opportunities for clinical and post-market stage products.
Source: Acorda Therapeutics