Immune checkpoint inhibitors (ICI) are now widely used at different stages of non-small cell lung cancers (NSCLC). Some clinical studies suggest that chemotherapy and immunotherapy have synergic activities, raising the question of the best therapeutic sequence. We studied the effect of chemotherapy in advanced NSCLC when administered after immunotherapy by nivolumab.

We performed a bicentric, retrospective, case-control study in two French hospitals. Patients with NSCLC treated with chemotherapy after nivolumab between January 2015 and January 2016 were included. Each case was matched on age and number of previous lines to one lung cancer patient who had not received nivolumab. Each CT-scanner has been reviewed and the objective response to chemotherapy was assessed for each patient according to the RECIST 1.1 criteria.

31 patients with advanced NSCL who had at least received one cycle of chemotherapy after progression under nivolumab in the inclusion period were matched to 31 controls. The median age for cases was 59 yo and the predominant tumoral histology was adenocarcinoma (77%). The progression free survival (PFS) was 2.95 months in the studied group vs 2.69 months (p=0.18) in the control group. At best response, disease control (DC=partial response and stable disease) was better in the case group than in the control group (58% vs 39%, p 0.127). Cases were about five times more likely to get objective response to best evaluation than controls (OR=5.043 [95%CI: 0.975-26.086; p=0.054). The overall survival (OS) was 7.3 months in the case group and 3.3 months in the control group (p=0.074). Patients who have been treated with targeted therapy instead of chemotherapy and patients with squamous lung cancer had worst PFS and OS.

In advanced NSCLC, the chemotherapy progression free survival does not seem higher when administered after nivolumab. However, when administered post-nivolumab, traditional chemotherapy has 5 times more chances to achieve objective response and seems to improve overall survival of cases. Pooled analysis with other similar studies might be interesting for a next step.