Drug comparisons: why are they so difficult?

Comparing therapeutic agents in a drug class can be difficult. This article examines the ways in which the triptans can be and have been compared and evaluates the advantages and disadvantages of the approaches. Direct comparative trials are clearly the best method for evaluating the triptans, however, there is a scarcity of this type of data on the currently available compounds. Indirect comparison such as meta-analysis is a second method of comparing these agents but only serves as an estimate of relative efficacy or safety based on a comparison of pooled data derived from a number of different trials for each agent. Comparison of the data found in the regulatory documents represents another type of indirect comparison that can be done so long as the data is presented in a consistent format across products.