Efficacy and safety analysis of adjuvant atezolizumab in non-small cell lung cancer patients in China: A single center retrospective analysis.

e20007 Background: Atezolizumab after adjuvant chemotherapy has become a promising treatment option for patients with resected early-stage NSCLC. We aimed to retrospective analysis the efficacy and safety for patients who received adjuvant atezolizumab after adjuvant platinum-based chemotherapy in real world. Methods: This study is a single center, retrospective study. Eligible patients were 18 years or older with completely resected stage IB (tumours ≥4 cm) to IIIA NSCLC per the Union Internationale Contre le Cancer and American Joint Committee on Cancer staging system (8th edition). The surgery requires lobectomy combined with mediastinal lymph node dissection, and the surgical margin is negative. Patients whose tumours expressed PD-L1 on 1% or more of tumour cells (Dako 22C3) receive adjuvant atezolizumab (1200 mg every 21 days; for 16 cycles or 1 year) after adjuvant platinum-based chemotherapy (up to four cycles). We assessed 1-year and 2-year DFS rates and OS rates. Safety of immunotherapy was evaluated in all patients. Results: From June 21, 2022 to December 19, 2024, we provided adjuvant atezolizumab to 20 patients who underwent radical surgery diagnosed non-small cell lung cancer including 12 squamous and 8 non-squamous. There were 10 patients in the stage IB-IIB and 10 in the stage IIIA. 13 patients got lymph node metastasis (3 for pN1 and 10 for pN2). After radical surgery, patients need to complete up to 4 cycles of adjuvant chemotherapy. During the chemotherapy phase, 8 patients received carboplatin plus pemetrexed, 12 received platinum plus taxanes (1 for cisplatin and 11 for carboplatin). The median number of adjuvant chemotherapy cycles received was four (only 1 patient for 3cycles, 19 patients for 4 cycles). All the patients had tumours expressing PD-L1 on 1% or more of tumour cells per Dako 22C3, including 6 patients had PD-L1 TPS≥50%. The median interval between the last chemotherapy and the first immunotherapy is 39 days. At a median follow-up time of 14.5 months, 7 patients completed 16 cycles of atezolizumab, 9 patients continued immunotherapy, 1 patient discontinued due to irAE, and 3 patients experienced disease progression. Among all patients, the 1-year and 2-year DFS rates were 95% and 85%, and the 1-year and 2-year OS rates were 100% and 95%, respectively. The median DFS and OS have not been reached. The most common atezolizumab-related adverse events were hypothyroidism in 3 patients, hyperthyroidism in 2 patients, psoriasis in 1 patient and myocarditis in 1 patient. All the irAE were grade 2. Conclusions: Based on the results of our single center retrospective study, the adjuvant atezolizumab treatment strategy is an effective and safe novel model for early lung cancer patients undergoing radical resection.