An Evidenced-Based Prior for Estimating the Treatment Effect of Phase III Randomized Trials in Oncology
Purpose: The primary results of phase III oncology trials may be challenging to interpret, given that such results are generally based on meeting P-value thresholds. The probability of whether a treatment is beneficial, although a more intuitive summary of the results, is not provided by most trials. In this study, we developed and released a user-friendly tool that calculates the probability that a treatment studied in a phase III oncology trial is beneficial using published summary statistics. Methods: We curated the primary time-to-event outcomes of 415 phase III, superiority design, therapeutic randomized controlled trials of oncologic treatments enrolling 338,600 patients and published between 2004 and 2020. A phase III oncology-specific prior probability distribution for the treatment effect was developed based on an estimated three-component zero-mean mixture distribution of the observed z-scores. Using this prior, we computed the probability of any benefit (hazard ratio < 1) an