Abstract
INTRODUCTION: Our preclinical work suggests that low-dose angiogenesis inhibition could potentiate programmed cell death protein 1 and programmed death-ligand 1 (PD-L1) blockade. In a cohort of our multicenter phase 1b and 2 study (NCT03083041), promising antitumor activity was observed with camrelizumab plus low-dose apatinib in chemotherapy-pretreated patients with advanced nonsquamous NSCLC. We hereby reported the results in treatment-naive patients (cohort 4) from the same study. METHODS: Eligible patients had untreated advanced nonsquamous NSCLC with a high tumor mutational burden (TMB) (tissue TMB >10 mutations per megabase or blood TMB ≥1.54 mutations per megabase) and without sensitizing EGFR or ALK alterations. Patients received camrelizumab 200 mg intravenously every 2 weeks plus apatinib 250 mg orally once daily. The primary end point was the objective response rate (ORR) per investigator. RESULTS: A total of 25 patients were enrolled and treated. A total of 10 (40.0%) confirmed partial responses and 13 (52.0%) stable diseases were observed. The ORR was 40.0% (95% confidence interval [CI]: 21.1-61.3) and disease control rate was 92.0% (95% CI: 74.0-99.0). With a median follow-up of 19.5 months, the median progression-free survival was 9.6 months (95% CI: 5.5-not reached), whereas the overall survival was not reached; the median duration of response was 15.6 months (95% CI: 3.8-not reached). Similar ORR and progression-free survival were observed regardless of PD-L1 tumor proportion score (≥1% versus <1%). The most common treatment-related grade 3 or higher adverse events were increased gamma-glutamyltransferase (24.0%), increased alanine aminotransferase (16.0%), and abnormal hepatic function (16.0%). CONCLUSIONS: Frontline camrelizumab plus low-dose apatinib exhibited promising clinical activity with acceptable safety in patients with advanced nonsquamous NSCLC regardless of PD-L1 expression.