Outcomes from salvage chemotherapy or pembrolizumab beyond progression with or without local ablative therapies for advanced non-small cell lung cancers with PD-L1 ≥50% who progress on first-line immunotherapy: Real-world data from a European cohort

Background: In this real-world multicenter study we addressed the activity of post-progression anticancer treatments after first-line pembrolizumab in advanced non-small cell lung cancer (NSCLC) patients with PD-L1 ≥50%. Methods: Clinico-pathological data of PD-L1 ≥50% advanced NSCLCs who failed first-line pembrolizumab were collected in 14 Oncologic Centers from different European countries. Types of subsequent anticancer treatment and outcomes on salvage chemotherapy or pembrolizumab beyond progression with or without the addition of local ablative therapies were reported. Results: Out of 173 patients, 100 had progressed on pembrolizumab, of which 60 patients (60%) met eligibility criteria and were treated with either salvage chemotherapy (42/60, 70%) or pembrolizumab beyond progression (18/60, 30%). Overall, median age was 66 years, 63.3% were male, 60.0% had a performance status of 0-1, 88.3% were smokers and 61.7% had adenocarcinoma histology. In patients evaluable for response, objective response rate to salvage chemotherapy was 41.9%, with no significant difference according to the type of regimen (42.9% for platinum-based and 40.0% for single-agent chemotherapy). Median progression-free survival (PFS) to salvage chemotherapy was 4.5 months. Among patients treated with pembrolizumab beyond progression, 13 out of 18 patients (72.2%) had progressive disease in ≤2 organ sites, of whom 9 (69.2%) were managed with the addition of local ablative therapies consisting of radiation at progressive lesion(s). No significant difference was noted in terms of post-progression survival between the salvage chemotherapy and the pembrolizumab beyond progression groups of patients (6.9 versus 8.1 months, respectively, P=0.08). Conclusions: In PD-L1 ≥50% advanced NSCLCs who progress on first-line pembrolizumab, salvage chemotherapy is associated with a remarkable anticancer activity, while select patients may benefit from continuation of pembrolizumab beyond progression, with the possible addition of local ablative radiotherapy in oligoprogressive cases.