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.