Can ad hoc analyses of clinical trials help personalize treatment decisions?

<p> The value of <em> ad hoc </em> analyses of clinical trials may not be clear. <em> Ad hoc </em> analyses are carried out after developing analysis plans and are considered exploratory in nature. Such analyses should be conducted on a &lsquo;rational&rsquo; biological basis, rather than &lsquo;aimless&rsquo; data dredging. <em> Ad hoc </em> analyses are done to generate new hypotheses that guide future research studies. Such retrospective analyses are of great value, especially if the differences for the primary outcome (adequately powered) were not detected. Analyses of positive trials can also identify populations that are treatment&hyphen;resistant or susceptible to adverse effects. <em> Ad hoc </em> analyses are highly underutilized to guide future studies to personalize treatment recommendations, but could have a great potential to personalize treatment decisions.</p>