Simon’s two-stage designs are frequently used in phase II single-arm trials for efficacy studies. A concern ofsafety studies is too many patients who experience an adverse event. We show that Simon’s two-stage designsfor efficacy studies can be similarly used to design a two-stage safety study by modifying some of the designparameters. Given the type I and II error rates and the proportion of adverse events experienced in the firststage cohort, we prescribe a procedure whether to terminate the trial or proceed with a stage 2 trial by recruitingadditional patients. We study the relationship between a two-stage design with a safety endpoint and an efficacyendpoint as well as use simulation studies to ascertain their properties. We provide a real-life application and afree R package gen2stage to facilitate direct use of two-stage designs in a safety study.

We develop a nature-inspired stochastic population-based algorithm and call it discrete particle swarm optimization tofind extended two-stage adaptive optimal designs that allow three target response rates for the drug in a phase II trial.Our proposed designs include the celebrated Simon’s two-stage design and its extension that allows two target responserates to be specified for the drug. We show that discrete particle swarm optimization not only frequently outperformsgreedy algorithms, which are currently used to find such designs when there are only a few parameters; it is also capableof solving design problems posed here with more parameters that greedy algorithms cannot solve. In stage 1 of ourproposed designs, futility is quickly assessed and if there are sufficient responders to move to stage 2, one tests one ofthe three target response rates of the drug, subject to various user-specified testing error rates. Our designs aretherefore more flexible and interestingly, do not necessarily require larger expected sample size requirements thantwo-stage adaptive designs. Using a real adaptive trial for melanoma patients, we show our proposed design requires onehalf fewer subjects than the implemented design in the study.

BACKGROUND: Initial primary head and neck cancer (IPHNC) is associated with second primary lung cancer (SPLC). We studied this association in a population with a high proportion of African American (AA) patients. METHODS: Patients with IPHNC and SPLC treated between 2000 and 2017 were reviewed for demographic, disease, and treatment-related characteristics and compared to age-and-stage-matched controls without SPLC. Logistic and Cox regression models were used to analyze the relationship of these characteristics with the development of SPLC and overall survival (OS). RESULTS: Eighty-seven patients and controls were compared respectively. AA race was associated with a significantly higher risk of developing SPLC (OR 2.92, 95% CI 1.35-6.66). After correcting for immortal time bias, patients with SPLC had a significantly lower OS when compared with controls (HR 0.248, 95% CI 0.170-0.362). CONCLUSIONS: We show that AA race is associated with an increased risk of SPLC after IPHNC; reasons of this increased risk warrant further investigation.