Futility in Clinical Trials

Hypersensitivity to CGRP as a predictive biomarker of migraine prevention with erenumab

BACKGROUND

The present study aimed to investigate the predictive value of calcitonin gene-related peptide (CGRP)-induced migraine attacks for effectiveness to erenumab treatment in people with migraine.

METHODS

In total, 139 participants with migraine underwent a single experimental day involving a 20-min infusion with CGRP. Following this, the participants entered a 24-week treatment period with erenumab. The primary endpoints were the predictive value of CGRP-induced migraine attacks on the effectiveness of erenumab, defined as ≥50% reduction in monthly migraine days, or ≥ 50% reduction in either monthly migraine or monthly headache days of moderate to severe intensity.

RESULTS

Among participants with CGRP-induced migraine attacks, 60 of 99 (61%) achieved ≥50% reduction in monthly migraine days during weeks 13-24 with erenumab. Conversely, 13 of 25 (52%) where CGRP infusion did not induce a migraine achieved the same endpoint (p = 0.498). There were no significant differences between the ≥50% reduction in either monthly migraine or monthly headache days of moderate to severe intensity between CGRP-sensitive and non-sensitive participants (p = 0.625).

CONCLUSIONS

Our findings suggest that the CGRP-provocation model cannot be used to predict erenumab's effectiveness. It remains uncertain whether this finding extends to other monoclonal antibodies targeting the CGRP ligand or to gepants.Trial Registration: The study was registered at ClinicalTrials.gov (NCT04592952).

Factors Associated With Premature Termination of Hyperacute Stroke Trials: A Review

BACKGROUND

We performed a review of acute stroke trials to determine features associated with premature termination of trial enrollment, defined by the authors as not meeting preplanned sample size.

METHODS AND RESULTS

MEDLINE was searched for randomized clinical stroke trials published in 9 major clinical journals between 2013 and 2022. We included randomized clinical trials that were phase 2 or 3 with a preplanned sample size ≥100 and a time-to-treatment within 24 hours of onset for transient ischemic attack, ischemic stroke, or intracerebral hemorrhage. Data were abstracted on trial features including trial design, inclusion criteria, imaging, location and number of sites, masking, treatment complexity, control group (standard therapy, placebo), industry involvement, and preplanned stopping rules (futility and efficacy). Least absolute shrinkage and selection operator regression was used to select the most important factors associated with premature termination; then, a multivariable logistic regression was fit including only the least absolute shrinkage and selection operator selected variables. Of 1475 studies assessed, 98 trials met eligibility criteria. Forty-five (46%) trials were prematurely terminated, of which 27% were stopped for benefit/efficacy, 20% for lack of money/slow enrollment, 18% for futility, 16% for newly available evidence, 17% for other reasons, and 4% due to harm. Complex trials (adjusted odds ratio [aOR], 2.76 [95% CI, 1.13-7.49]), presence of a futility rule (aOR, 4.43 [95% CI, 1.62-17.91]), and exclusion of prestroke dependency (none/slight disability only; aOR, 2.19 [95% CI, 0.84-6.72] versus dependency allowed) were identified as the strongest predictors.

CONCLUSIONS

Nearly half of acute stroke trials were terminated prematurely. Broadening inclusion criteria and simplifying trial design may decrease the likelihood of unplanned termination, whereas planned futility analyses may appropriately terminate trials early, saving money and resources.