An evaluation of a Simon 2-Stage phase II clinical trial design incorporating toxicity monitoring

Phase II clinical trials are usually designed to measure efficacy but patient safety is also a very important aspect. Previous authors suggested a methodology that allows one to monitor the cumulative number of toxic events after each patient is treated, which is also known as continuous toxicity monitoring. In this work we describe how to combine the continuous toxicity monitoring methodology with the Simon 2-Stage design for response. Then we investigate through simulation the combined procedure's type I and type II error rates under various combinations of design parameters. We include the underlying relationship between toxicity and response in our examination of the error rates.