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    Reporting Gaps in Migraine Clinical Trial Results

    Global database assessing migraine trial results shows gaps in reporting of clinical trial data, according to new research at CPMCRI

    September 5, 2014 (San Francisco, CA)

    Results from 40 percent of clinical trials for migraine on the world’s registries are not readily available more than two years after study completion, according to a thorough analysis and scorecard for public availability of results.

    Global findings from the Repository of Registered Migraine Trials (RReMiT) database were published in the September 5, 2014 issue of Neurology®, the medical journal of the American Academy of Neurology.

    To capture a snapshot of registered clinical trials related to migraine and a scorecard of the availability of trial results, Michael Rowbotham (M.D.)—Scientific Director of the California Pacific Medical Center Research Institute (CPMCRI) and senior study author—and colleagues created RReMiT. The initiative follows their earlier work in creating a similar database for registered analgesic trials (RReACT) of common pain disorders. The new survey of migraine trials includes results from trials of 15 major registries accessible through the World Health Organization International Clinical Trials Registry Platform (ICTRP).

    “Transparency in research requires public access to unbiased information prior to trial initiation and openly available results upon study completion,” said Dr. Rowbotham. “By initiating RReMiT, our goal was to enable greater public access to the results of clinical research in migraine treatment and prophylaxis.”

    Clinical trials conducted in the U.S. are required to be registered on— the world’s largest global registry and a service of the National Institutes of Health (NIH)—and certain categories of industry-sponsored trial results must be posted within one year of a study’s completion.

    Dr. Rowbotham and colleagues Faustine Dufka (B.A., lead study author and UCSF medical student) and Robert Dworkin (Ph.D., Professor in the Departments of Anesthesiology and Neurology at the University of Rochester School of Medicine and Dentistry) analyzed trial registration, registry functionality, and results reporting on all 15 primary registries in the ICTRP for trials of migraine treatment and migraine prophylaxis (totaling 447 investigational agents), excluding device studies.

    Trial results were searched for in the peer-reviewed literature and the ‘grey literature’ (conference abstracts and/or posters, and press releases), and only unique trials were analyzed. Results were sought except for trials shown as actively recruiting, withdrawn prior to subject enrollment, or not yet open for recruitment.

    Overall, 237 trials were eligible for a results search. Of 163 trials completed at least one year earlier, 57 percent had peer-reviewed literature results, and registries/grey literature added another 13 percent.

    The main factor associated with the availability of results was time since study completion. Also, trials registered on and trials with industry as the primary sponsor were significantly more likely to have results compared with those not industry-sponsored. Recently completed trials appeared to rarely have publicly available results; two years after completion, the peer-reviewed literature contained results for less than 60 percent of completed migraine trials.

    “By searching all the major clinical trial registries and analyzing nearly 300 migraine studies, the RReMiT database is an important contribution to the literature on trial registration and transparency in reporting of results,” said Dr. Rowbotham , noting that peer-reviewed literature may be an imperfect and incomplete resource for constructing evidence-based guidelines.

    “Biased recommendations could result if the published literature does not accurately reflect the full range of potentially available results. Even for large, well-designed drug registration trials, studies with negative results are much less likely to be published.”

    The study was funded by the ACTTION initiative, a public-private partnership between the U.S. Food and Drug Administration, NIH, industry, and academia. The RReMiT and RReACT databases are freely accessible via the ACTTION website (