Comparison of error rates in single-arm versus randomized phase II cancer clinical trials.
PURPOSE To improve the understanding of the appropriate design of phase II oncology clinical trials, we compared error rates in single-arm, historically controlled and randomized, concurrently controlled designs. PATIENTS AND METHODS We simulated error rates of both designs separately from individual patient data from a large colorectal cancer phase III trials and statistical models, which take into account random and systematic variation in historical control data. RESULTS In single-arm trials, false-positive error rates (type I error) were 2 to 4 times those projected when modest drift or patient selection effects (eg, 5% absolute shift in control response rate) were included in statistical models. The power of single-arm designs simulated using actual data was highly sensitive to the fraction of patients from treatment centers with high versus low patient volumes, the presence of patient selection effects or temporal drift in response rates, and random small-sample variation in historical controls. Increasing sample size did not correct the over optimism of single-arm studies. Randomized two-arm design conformed to planned error rates. CONCLUSION Variability in historical control success rates, outcome drifts in patient populations over time, and/or patient selection effects can result in inaccurate false-positive and false-negative error rates in single-arm designs, but leave performance of the randomized two-arm design largely unaffected at the cost of 2 to 4 times the sample size compared with single-arm designs. Given a large enough patient pool, the randomized phase II designs provide a more accurate decision for screening agents before phase III testing.
Tang
Hui
H
Mayo Clinic, 200 1st St SW, Rochester, MN 55905, USA. h.tang@mayo.edu
Foster
Nathan R
NR
Grothey
Axel
A
Ansell
Stephen M
SM
Goldberg
Richard M
RM
Sargent
Daniel J
DJ
D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D016022:Case-Control Studies; D017322:Clinical Trials, Phase II as Topic / Q000379:methods* / Q000592:standards; D015179:Colorectal Neoplasms / Q000188:drug therapy*; D003198:Computer Simulation; D023381:Endpoint Determination; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D011379:Prognosis; D016032:Randomized Controlled Trials as Topic / Q000379:methods* / Q000592:standards; D012107:Research Design; D018401:Sample Size; D015996:Survival Rate
D000970:Antineoplastic Agents