Accounting for Interim Analyses in the Assessment of Program Expected Net Present Value

Abstract

The calculation of the expected net present value of a clinical development program involves the integration of future outcomes with their timing, cash flows, and associated probabilities, both subjective and relative frequency. As applied to clinical trials, the outcomes are the clinical trial results, typically timed at the completion of the trial. When the trial design includes interim analyses with the possibility of early trial stopping with an efficacy or futility conclusion, we show that the expected net present value of the program can be meaningfully influenced through the inclusion of early stopping times and probabilities in the expected net present value calculations. This approach can be applied prior to the start of the trial, and it can also be applied during the course of the trial. In the latter case, given that interim analyses have been passed, the trial-stopping probabilities change, with resulting effects on the expected net present value. In both cases, the improved expected net present value figures should lead to better portfolio decisions.