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Updated: May 19, 2026
10:46
A Method of Trigonometric Modelling of Seasonal Variation Demonstrated with Multiple Sclerosis Relapse Data
Published on: December 9, 2015
Time to first relapse as an endpoint in multiple sclerosis clinical trials
M P Sormani1, A Signori, P Siri
1Department of Health Sciences (DISSAL), University of Genova, Via Pastore 1, Genova, 16132, Italy. mariapia.sormani@unige.it
Multiple Sclerosis (Houndmills, Basingstoke, England)
|August 24, 2012
Summary
Time to first relapse is a viable endpoint for multiple sclerosis (MS) clinical trials, potentially requiring fewer patients than annualized relapse rate (ARR) and allowing for more ethical placebo use.
Area of Science:
- Neurology
- Clinical Trial Design
- Pharmacology
Background:
- Ethical concerns arise from placebo use in multiple sclerosis (MS) trials due to numerous effective therapies.
- Need for novel clinical trial designs in MS research is evident.
Purpose of the Study:
- To assess the efficacy of time to first relapse as a clinical trial endpoint for multiple sclerosis.
- Compare sample size requirements for time to first relapse versus annualized relapse rate (ARR) endpoints.
Main Methods:
- Utilized a model simulating time to first relapse in MS patients.
- Estimated sample sizes for trials using time to first relapse as an outcome.
- Compared these estimates with those for trials using ARR.
Main Results:
- Trials using time to first relapse are feasible and require similar or smaller sample sizes compared to ARR-based trials.
- For low ARR (0.4/year), 1-year trials detecting a 30% effect need 470 patients/arm for time to first relapse vs. 540 for ARR.
- Time to first relapse endpoint demonstrates comparable power to ARR.
Conclusions:
- Time to first relapse is a powerful and potentially useful primary outcome for MS trials.
- This endpoint supports ethically sound trial designs, allowing placebo patients to switch to active drugs upon relapse.
- Potential drawback: loss of data for other fixed time-point endpoints.
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