The following is a summary of “Outcome Reporting Bias in Clinical Trials Researching Disease-Modifying Therapy in Patients With Multiple Sclerosis,” published in the February 2024 issue of Neurology by Lemmens et al.

While the development of immunomodulatory drugs for multiple sclerosis (MS) has surged, concerns regarding publication bias threaten the validity of trial results due to selective reporting based on their significance.

Researchers conducted a retrospective study to thoroughly investigate the presence of outcome reporting bias in these trials and explore potential underlying factors.

They identified clinical trials assessing the effectiveness and safety of immunomodulatory drugs in patients diagnosed with MS, registered on ClinicalTrials.gov (September 2007 to the end of 2018). Details regarding study design, funding sources, and primary and secondary outcome measures were extracted from the registry. They reviewed the timing of registration concerning study initiation and any subsequent modifications to the intended outcomes. They identified related publications across various bibliographic databases using the trial registration number. Primary and secondary outcomes, as registered, were documented for each trial and compared with the outcomes reported in the main trial publication.

The results showed that of the 535 eligible registered clinical trials identified through ClinicalTrials.gov, 101 had corresponding publications. Discrepancies between registered and published primary and secondary outcomes were observed in 95% of these trials, with discrepancies between registered and published primary outcomes found in 26 publications. About 44%of the published secondary outcomes were absent from the registry, and a similar proportion of registered and nonregistered reported positive primary efficacy outcomes (favored the intervention). Nonindustry-funded and open-label trials in MS demonstrated a higher tendency for selective primary outcome reporting, although these findings did not reach statistical significance. Two-thirds of the trials were registered in ClinicalTrials.gov before the trial start date, and 62% of trials made amendments to registered outcomes during or after the trial period.

Investigators concluded that despite prevalent selective outcome reporting in MS drug trials, proposed methods aim to mitigate this bias in future research.

Source: neurology.org/doi/10.1212/WNL.0000000000208032