Neoadjuvant SHR-1701 with or without chemotherapy in unresectable stage III NSCLC (TRAILBLAZER): Efficacy, safety and feasibility of surgical conversion outcomes from a proof-of-concept, phase 2 trial.

Abstract

8082 Background: Consolidation immunotherapy after chemoradiation is the standard of care for unresectable stage III NSCLC. Addition of immunotherapy-based induction treatment may further improve outcome, partly by enabling surgery. We conducted a proof-of-concept, phase 2 trial to assess neoadjuvant SHR-1701 (an anti-PD-L1/TGF-β bifunctional fusion protein) with or without chemotherapy, followed by surgery or radiotherapy in unresectable stage III NSCLC and without EGFR/ ALK alterations. Methods: Patients with MDT-assessed surgically unresectable disease were given 3 cycles of neoadjuvant SHR-1701 (30 mg/kg Q3W) with or without chemotherapy (paclitaxel 175 mg/m2 Q3W + carboplatin AUC = 5 Q3W).Patients with PD-L1 TPS < 50% received combination therapy (arm A) and those with PD-L1 TPS ≥50% were randomized (1:1) to receive combination therapy (arm B) or SHR-1701 alone (arm C). After reassessment by MDT, patients received either surgery or definitive radiotherapy (60 Gy/30 fractions) plus concurrent cisplatin (30 mg/m2 QW), all followed by consolidation SHR-1701 for 16 cycles. The primary endpoints were post-induction objective response rate (ORR) and 18-month event-free survival (EFS) rate. Arm A+B (patients receiving neoadjuvant chemoimmunotherapy) was the primary analysis cohort. Results: Between Nov. 20, 2020 and Jan. 27, 2022, 107 patients were enrolled (arm A/B/C, n = 88/9/10). Median follow-up was 22.2 months. In arm A+B, both primary endpoints were met, with a post-induction ORR of 58% (95% CI 47-68) and an 18-month EFS rate of 56.6% (95% CI 45.2-66.5). In arm C, the post-induction ORR was 40% (95% CI 12-74) and 18-month EFS rate was 77.1% (95% CI 34.5-93.9). 24-month overall survival rate was 78.3% (95% CI 68.0-85.7) in arm A+B and 100% in arm C. Overall, 27 (25% of 107; arm A+B/C, n = 24/3) patients underwent surgery; all achieved R0 resection. Among them, 12 (44%) MPR and seven (26%) pCR were recorded. The 18-month EFS rate was 74.1% (95% CI 53.2-86.7) in resected patients and 57.3% (43.0-69.3) in those receiving radiotherapy. Across arms, all grade ≥3 TRAEs with frequency ≥10% were hematological toxicities. No new safety signals were identified. Conclusions: NeoadjuvantSHR-1701 with chemotherapy, followed by surgery or radiotherapy, showed promising anti-tumor activity with a tolerable safety profile in unresectable stage III NSCLC. We provided first evidence that surgical conversion was feasible in a notable proportion of patients, and was associated with better survival outcomes. Clinical trial information: NCT04580498 .