Stereotactic body radiotherapy with sequential tislelizumab and chemotherapy as neoadjuvant therapy in patients with resectable non-small-cell lung cancer in China (SACTION01): a single-arm, single-centre, phase 2 trial.

Background: Neoadjuvant immunotherapy with chemotherapy improves outcomes in patients with resectable non-small-cell lung cancer (NSCLC). Given its immunomodulating effect, we investigated whether stereotactic body radiotherapy (SBRT) enhances the effect of immunochemotherapy.

Methods: The SACTION01 study was a single-arm, open-label, phase 2 trial that recruited patients who were 18 years or older and had resectable stage IIA-IIIB NSCLC from the Sun Yat-sen University Cancer Center, Guangzhou, China. Eligible patients received SBRT (24 Gy in three fractions) to the primary tumour followed by two cycles of 200 mg intravenous PD-1 inhibitor, tislelizumab, plus platinum-based chemotherapy. Surgical resection was performed 4-6 weeks after neoadjuvant treatment. The primary endpoint was major pathological response (MPR), defined as no more than 10% residual viable tumour in the resected tumour. All analyses were conducted on an intention-to-treat basis, including all patients who were scheduled for neoadjuvant treatment. The trial was registered with ClinicalTrials.gov (NCT05319574) and is ongoing but closed to recruitment.

Findings: Between May 18, 2022, and June 20, 2023, 46 patients (42 men and four women) were enrolled and scheduled for neoadjuvant treatment. MPR was observed in 35 (76%, 95% CI 61-87) of 46 patients. The second cycle of immunochemotherapy was withheld in four (9%) patients due to pneumonia (n=2), colitis (n=1), and increased creatinine (n=1). Grade 3 or worse adverse events related to neoadjuvant treatment occurred in 12 (26%, 95% CI 14-41) patients. The most frequent treatment-related adverse event (TRAE) was alopecia (16 [35%] patients), and the most frequent grade 3 or worse TRAE was neutropenia (six [13%]). There was one treatment-related death, caused by neutropenia. No deaths within 90 days of surgery were reported.

Interpretation: Preoperative SBRT followed by immunochemotherapy is well tolerated, feasible, and leads to a clinically significant MPR rate. Future randomised trials are warranted to support these findings.

Funding: BeiGene.