NSCLC with uncommon EGFR mutations treated with atezolizumab plus bevacizumab and chemotherapy

Abstract

Objectives: For refractory NSCLC patients with EGFR mutations, recent studies have demonstrated a favorable response to the combination of anti-angiogenic therapy and checkpoint inhibition but included only very few patients with uncommon EGFR mutations for which treatment options are still limited despite new targeted treatments.

Materials and methods: Sixteen stage IV NSCLC patients with uncommon EGFR mutations from 9 different German centers were treated in first or further line with Atezolizumab, Bevacizumab, Carboplatin and (nab-)Paclitaxel (ABCP). PFS was evaluated from start of ABCP and OS from time of initial diagnosis of stage IV.

Results: Patients with either an Exon 20 insertion (n = 9) or other uncommon EGFR mutations (n = 7) received ABCP in first, second or further line. Nine patients had received a TKI therapy in first line with an ORR of 66.7 % and a median time-to-next-treatment of 6.7 months. After a median number of 4 ABCP cycles, 4 patients (25.0 %) required a dose reduction of chemotherapy and 5 patients (31.3 %) suffered from grade 3 or 4 toxicity. Overall response rate was 81.3 % and disease control rate 87.5 %. 14 patients (87.5 %) received a maintenance with AB and the median follow-up after initial diagnosis was 24.3 months. Median PFS was 13.6 months for both the entire cohort and for Exon 20 insertions. Corresponding median OS was either not reached or 30.7 months. Landmark analysis at 12 months gave a PFS of 42.8 % and an OS of 93.3 %. Four patients were rechallenged with ABCP while progressing under maintenance and responded again. In further line therapy, clinical benefit was achieved in all of 3 patients receiving Amivantamab, but in only one of four patients receiving mobocertinib.

Conclusion: In this retrospective analysis, ABCP achieves an encouraging outcome for patients with uncommon EGFR mutations and is a valuable option in the early treatment course.

Keywords: Exon 20 insertion; Non-small cell lung cancer; Quadruple therapy; Uncommon EGFR mutation.