Clinical trial evidence of quality-of-life effects of disease-modifying therapies for multiple sclerosis: a systematic analysis

Background: Increasingly, patients, clinicians, and regulators call for more evidence on the impact of innovative medicines on quality of life (QoL). We assessed the effects of disease-modifying therapies (DMTs) on QoL in people with multiple sclerosis (PwMS).

Methods: Randomized trials assessing approved DMTs in PwMS with results for at least one outcome referred to as "quality of life" were searched in PubMed and ClinicalTrials.gov.

Results: We identified 38 trials published between 1999 and 2023 with a median of 531 participants (interquartile range (IQR) 202 to 941; total 23,225). The evaluated DMTs were mostly interferon-beta (n = 10; 26%), fingolimod (n = 7; 18%), natalizumab (n = 5; 13%), and glatiramer acetate (n = 4; 11%). The 38 trials used 18 different QoL instruments, with up to 11 QoL subscale measures per trial (median 2; IQR 1-3). QoL was never the single primary outcome. We identified quantitative QoL results in 24 trials (63%), and narrative statements in 15 trials (39%). In 16 trials (42%), at least one of the multiple QoL results was statistically significant. The effect sizes of the significant quantitative QoL results were large (median Cohen's d 1.02; IQR 0.3-1.7; median Hedges' g 1.01; IQR 0.3-1.69) and ranged between d 0.14 and 2.91.

Conclusions: Certain DMTs have the potential to positively impact QoL of PwMS, and the assessment and reporting of QoL is suboptimal with a multitude of diverse instruments being used. There is an urgent need that design and reporting of clinical trials reflect the critical importance of QoL for PwMS.