Phase II stopping rules employing response rates and early progression

2553 Background: Drug development in oncology has become increasingly resource intensive. Anything that might accelerate drug development would benefit patients and drug developers. Traditionally, tumour response rates (RR) have been used to assess the efficacy of new agents in phase II trials. High rates of early progression of disease (EPD) may also indicate lack of drug efficacy, and this endpoint has the potential to shorten trials compared to assessing RR alone. This work seeks to create a set of rules that will allow phase II drug assessment employing both RR and EPD. Previous work on this subject suffered from insufficient power, as determined by the authors [Freidlin et al, J Clin Oncol, 20:599, 2002]. Methods: Using TreeAge Pro Healthcare software, we created a computer model that would accept specified trial parameters and determine through simulations stopping rules based on observed number of responses and EPDs to achieve the desired power and alpha error for a single-armed two-stage study with 15 patients in each stage. The null hypothesis (H(nul)) specified the response rate (rr(nul)) and early progressive disease rate (epd(nul)) that would render a drug uninteresting for further development, such that: H(nul): rr LE rr(nul) & epd GE epd(nul), where rr is that actual response rate observed and epd is the actual rate of early progression. Similarly, the alternate hypothesis (H(alt)) specified the response rate (rr(alt)) and early progressive disease rate (epd(alt)) that would render a drug interesting for further development, such that: H(alt): rr GE rr(alt) or epd LE epd(alt). (LE, less than, equal to; GE, greater than, equal to) Results: Conclusions: The simulation was able to establish stopping rules for observed number of responses and EPDs to achieve the desired error rates. Variations on the rules based on other trial sample types and design parameters will be detailed. [Table: see text] No significant financial relationships to disclose.