Real world experience of treatment and outcome in ALK-rearranged metastatic nonsmall cell lung cancer: A multicenter study from India.

BACKGROUND

Anaplastic lymphoma kinase (ALK) rearranged metastatic non-small cell lung cancer (NSCLC) comprises 5%-7% of all lung cancer and carries a good prognosis with available ALK-inhibitors. Majority of registration trials in ALK-inhibitors did not include Indian patients. Hence, this study was planned to analyze the outcome of Indian patients treated with ALK-inhibitors and associated challenges.

METHODS

This is a multi-center study in 5 major tertiary care cancer centers across India treating ALK-rearranged NSCLC patients from April 2013 to April 2019. ALK rearrangement was determined by Ventana immunohistochemistry with D5F3 clone and/or by break-apart FISH. Patients treated with ALK-inhibitors in any lines of treatment were included in this study. Patients were evaluated for clinicopathologic features, patterns of ALK-inhibitors use and outcome. Progression free-survival (PFS) and overall survival (OS) were calculated and data were censored on April 30, 2019.

RESULTS

A total of 274 patients were studied, out of which 250 patients received ALK inhibitor and were analyzed further for outcome. The median age was 50 years (range: 24-82) and male to female ratio of 1.17:1. ALK was evaluated by immunohistochemistry in majority of patients (97%), 3 patients by FISH and 3 more patients were evaluated by both methods. Sixty-five percent (n = 162) of the patients received ALK-inhibitor as first line therapy, 51 patients received ALK-inhibitor as switch maintenance therapy after initial chemotherapy. Crizotinib and Ceritinib were used in 88% and 12%, respectively. One patient received Alectinib. Forty-one percent of patients had CNS progression. After median follow up of 27 months (1-72 months), the median OS was 24.7 months with OS rate of 72%, 51%, and 18% at 1, 2, and 4-years respectively. Median OS was 21.2, 26, and 38 months in the first line ALK-inhibitors use (n = 162), switch maintenance group (n = 51) and second line ALK-inhibitors use (postchemotherapy progression) (n = 33), respectively. No baseline variable predicted PFS. Presence of brain metastasis (P = 0.039) and first line ALK-inhibitors use (P = 0.032) emerged as poor prognostic factor for OS on multivariate analysis. PFS rate was 70%, 47%, and 31% at 6, 12, and 18 months respectively.

CONCLUSION

This is one of the largest real-world data on outcome of ALK inhibitors in ALK-rearranged NSCLC from Asia. In absence of second line ALK inhibitor, initial chemotherapy followed by ALK-inhibitors (switch maintenance) had better outcome. This fact may be studied in individual patient data meta-analysis. Poor performance status and brain metastases at presentation are poor prognostic factors for overall survival. Second-line ALK inhibitor use crucial for better outcome and access to clinical trials are much needed in Indian patients.