REMATCH2201: A phase II study on reducing surgical margins in HPV-negative advanced HNSCC with neoadjuvant PD-1 inhibitor and AP chemotherapy.

Abstract

6011 Background: The standard of care for resectable HNSCC includes extensive surgical margins to ensure complete oncologic resection, often at the expense of significant functional impairment. Recent advancements in neoadjuvant PD-1 inhibitors with chemotherapy, have shown potential in achieving substantial tumor regressions. This study posits that such neoadjuvant immunochemotherapy can allow for narrower surgical margins without compromising oncological outcomes, potentially preserving vital anatomical structures and function. Methods: This single-center, phase II clinical study (NCT05459415) enrolled 52 patients with operable, HPV-negative locally advanced HNSCC. Participants received three cycles of the AP chemotherapy regimen combined with 200 mg of the PD-1 inhibitor Penpulimab. Tumor response was assessed via MRI and laryngoscopy after the second cycle. Patients achieving greater than 50% reduction in tumor size were selected for conservative-margin surgical resection. Surgical Protocol: If imaging or endoscopy identifies residual tumor, margins will be expanded 5-10mm beyond the tumor edges to ensure clear margins, confirmed by intraoperative frozen section analysis by dual pathologists, ensuring maximal oncologic safety and functional preservation. For patients achieving CR, surgical planning relies on prior diagnostic imaging and endoscopic outcomes to guide precise resections of the larynx and hypopharynx. Post-surgical adjuvant treatment was based on final pathology results, including further immunotherapy for nine cycles. Results: Of the initial cohort, 50 patients were evaluable for response; the objective response rate (ORR) stood at 96%, and a pathologic complete response (pCR) was observed in 40.7% of patients. Forty-seven patients proceeded to surgery, all maintaining laryngeal function, and 91.5% underwent reduced-margin resection based on deep imaging response, with a pCR achieved in 44.2% of these cases. The study noted clinical adverse events, including three unrelated deaths and two instances of severe postoperative complications. The 12-month and 24-month Event-Free Survival (EFS) rates were calculated at 97.62% and 89.28% respectively. The overall survival (OS) rate at 24 months was 92.85%. Conclusions: The REMATCH2201 trial supports the feasibility of reduced-margin surgery in patients with HPV-negative advanced HNSCC following effective neoadjuvant immunochemotherapy, without increasing the risk of oncologic recurrence. This approach importantly spares critical functional anatomy, advocating for a paradigm shift in the surgical management of these tumors. Nevertheless, further research in a multi-center, randomized controlled trial setting is required to substantiate these findings and refine protocols for broader application in clinical practice. Clinical trial information: NCT05459415 .