Five‐year survival and clinical correlates among patients with advanced non‐small cell lung cancer, melanoma and renal cell carcinoma treated with immune check‐point inhibitors in Australian tertiary oncology centres

AIMS: There is robust trial evidence for improved overall survival (OS) with immunotherapy in advanced solid organ malignancies. The real‐world long‐term survival data and the predictive variables are not yet known. Our aim was to evaluate factors associated with 3‐year and 5‐year OS for patients treated with immune checkpoint inhibitors (ICIs). METHODS: We performed a retrospective study of patients who received ICIs as management of advanced solid organ malignancies in two tertiary Australian oncology centres from 2012–2017. Data pertaining to clinical characteristics, metastatic disease burden, immune‐related adverse events (IRAEs) and tumour responses were collected and their relationship to survival examined. RESULTS: In this analysis of 264 patients, 202 (76.5%) had melanoma, 46 (17.4%) had non‐small cell lung cancer (NSCLC), 12 (4.5%) had renal cell carcinoma (RCC) and 4 (1.5%) had mesothelioma. The 5‐year OS rates were 42.1% in patients with melanoma, 19.6% with NSCLC, 75% with RCC, and none of the mesothelioma patients were alive at 5 years. In multivariate analysis, an ECOG score of 0 (Hazard ratio [HR] 0.39; 95% confidence interval [CI] 0.23–0.66; p < 0.001) and the occurrence of IRAE's of any grade (HR 0.61; 95% CI 0.37–0.95; p = 0.05) were associated with better 5‐year survival. The presence of bone metastases (HR 1.62; 95% CI 1.03–2.82; p = 0.05) and liver metastases (HR 1.76; 95% CI 1.07–2.89; p = 0.03) were associated with worse 5‐year survival. CONCLUSIONS: These results support the long‐term benefits of immunotherapy that in some patients, extend to at least 5 years. ECOG performance status of 0 and the occurrence of irAEs are associated with better long‐term survival. Survival is significantly influenced by metastatic site and cancer type. These predictive clinical correlates aid discussions and planning in the delivery of ICIs to patients.