Best practices in phase III clinical trials on DMTs for multiple sclerosis: a systematic analysis and appraisal of published trials.

Background: Great advances have been made in the field of multiple sclerosis (MS) therapy due to the publication of numerous randomised clinical trials (RCTs). In this study, we carried out a critical appraisal of phase III RCTs of disease-modifying therapies (DMTs) for MS published after 2010, intending to identify critical areas of improvement.

Methods: We performed a systematic search of published RCTs on MS from January 2010 until December 2021. RCTs were assessed using an ad-hoc tool. This tool was developed based on existing generic methodological instruments and MS-specific guidelines and methodological papers. It included 14 items grouped in 5 domains: methodological quality, adequacy and measurement of outcomes, adverse event reporting, applicability and relevance of results, and transparency and conflict of interest.

Results: We identified 31 phase III RCTs. Most of them were fully compliant in terms of sample size (87%), randomisation (68%), blinding (61%), participant selection (68%), adverse event reporting (84%) and clinical relevance (52%). Only a few were compliant in terms of participant description (6%), comparison (42%), attrition bias (26%), adequacy of outcome measures (26%), applicability (23%), transparency (36%) and conflict of interest (6%). None were compliant in terms of analysis and reporting of outcomes. The most common limitations related to the absence of comorbidity data, unjustified use of placebo, inadequacy of outcomes design and absence of protocol and/or prospective registration.

Conclusions: RCTs for DMTs in MS have relevant and frequent limitations. These should be addressed to enhance their quality, transparency and external validity.