ATLAS trial of adjuvant axitinib in patients with renal cell carcinoma: subgroup analyses with focus on axitinib dosing and racial groups

The ATLAS trial, investigating adjuvant axitinib versus placebo in renal cell carcinoma (RCC), was stopped for futility at a preplanned interim analysis. We report subgroup outcome analyses by ethnicity, time on treatment, dose modification and toxicity.Patient demographics, baseline characteristics, treatment duration and exposure and safety were analysed for Asian versus non-Asian patients treated with axitinib versus placebo. Disease-free survival (DFS) was analysed by ethnicity, treatment duration (≥1 versus <1 year), dose modification and adverse event (AE) grade.No DFS benefit was observed for Asian {hazard ratio (HR) 0.883 [95% confidence interval (CI) 0.638-1.220]} or non-Asian [HR 0.828 (95% CI 0.490-1.400)] patients treated with axitinib or placebo. Fewer Asian versus non-Asian patients were in the highest-risk group in axitinib (51.9% versus 72.3%) or placebo (51.5% versus 66.0%) arm. Highest-risk patients in both subgroups had no DFS benefit with either treatment. More axitinib-treated Asian versus non-Asian patients had dose reductions due to AEs (58.8% versus 46.0%; P = 0.028). Asian patients experienced more nasopharyngitis but less fatigue or asthenia than non-Asians. Among Asian patients, proteinuria, hypothyroidism, nasopharyngitis, and hypertension were more common in Japanese patients than Korean patients and more common in Korean patients than Chinese patients. Patients receiving axitinib >1 year versus ≤1 year did not have different DFS: HR 0.572 (95% CI 0.247-1.327); P = 0.1874. Compared with patients on stable axitinib dose, DFS was longer in patients with dose reduction [HR 0.458 (95% CI 0.305-0.687); P = 0.0001], whereas DFS was not different in those with dose escalation [HR 1.936 (95% CI 0.937-3.997); P = 0.0685]. DFS was not different in patients experiencing grade ≥2 versus <2 AEs within 6 months of initiating axitinib: HR 0.885 (95% CI 0.419-1.869); P = 0.7488.Asian versus non-Asian subgroup analysis revealed differences in AE experience and drug exposure. There were no DFS differences based on ethnicity or treatment duration, but axitinib dose reduction led to longer DFS.