Prospective Observational Comparison of Clinical Outcomes Between African-American and Caucasian Patients Receiving Second-Line Treatment With Pemetrexed for Advanced Non–Small-Cell Lung Cancer

Abstract

IntroductionThis prospective observational study evaluated the effect of race on disease control rate (DCR), progression-free survival (PFS), and overall survival (OS) in patients with NSCLC treated with second-line pemetrexed. Patients and MethodsEligibility criteria included stage IIIB or IV NSCLC patients receiving single-agent pemetrexed for second-line therapy in routine clinical practice. Noninferiority was evaluated using logistic regression analysis of DCR, controlling for predefined covariates. Noninferiority was considered if the upper 95% confidence bound on the adjusted odds ratio (OR) for Caucasian vs. African-American individuals was less than 1.78, corresponding to a difference in proportion of 14% assuming Caucasian individuals to have a DCR of approximately 50%. The bound was chosen to be half of the anticipated difference between treatment and no second-line treatment. PFS and OS were estimated using the Kaplan–Meier method. Tools were used to measure functional status and symptom burden. ResultsThe unadjusted DCR was 43.7% (117/268) for Caucasian and 45.0% (27/60) for African-American individuals (unadjusted OR, 0.95; 95% confidence interval [CI], 0.54-1.66). The adjusted OR in the final logistic regression model was 0.82 (95% CI, 0.43-1.58). This upper 95% confidence bound was within the prespecified acceptable bound of 1.78. Median PFS times (months) were 2.7 (95% CI, 2.4-3.4) for Caucasian and 3.0 (95% CI, 2.3-4.7) for African-American individuals (P = .91). Median OS times (months) were 6.7 (95% CI, 5.7-7.9) for Caucasian and 6.9 (95% CI, 4.5-8.9) for African-American individuals (P = .92). Baseline and functional status after baseline assessment and mean symptom burden did not differ substantially among races. ConclusionAfrican-American race was not considered to be a significant predictor of disease control after second-line treatment with pemetrexed.