Neoadjuvant tislelizumab combined with chemotherapy in locally advanced oral or oropharyngeal squamous cell carcinoma: A single-arm, phase II trial.

Abstract

e18072 Background: Previous studies confirmed locally advanced oral or oropharyngeal squamous cell carcinoma (LA OSCC or OPSCC) patients (pts) with a pathological response had higher probability of survival in neoadjuvant settings. Several ongoing trials of neoadjuvant immunotherapy in head and neck cancer showed promising results. However, the optimal regimen remains unclear. This trial aimed to evaluate the efficacy and safety of neoadjuvant therapy with anti-programmed cell death 1 (PD-1) mAb tislelizumab and chemotherapy, followed by surgery and adjuvant radiotherapy/chemoradiotherapy in LA OSCC or OPSCC. Methods: In this phase II, single-arm study, eligible pts aged 18-80 diagnosed with stage III-IV (AJCC v8) resectable or potentially resectable LA OSCC or OPSCC received neoadjuvant therapy with tislelizumab (200 mg), albumin-bound paclitaxel (260 mg/m2), and cisplatin (60-75 mg/m2) Q3W for 2 cycles, followed by surgery and adjuvant radiotherapy or concurrent chemoradiotherapy. The primary endpoint was major pathologic response (MPR). Secondary endpoints included pathological complete response (pCR), objective response rate (ORR), event-free survival (EFS), overall survival (OS) and safety. Results: Thirty-one pts were enrolled from Mar 2022 to Nov 2022, and completed neoadjuvant therapy, with an ORR of 61.3% (19/31) and CR rate of 6.5% (2/31). Of the 31 pts, 29 pts (18 OSCC, 13 OPSCC) successfully underwent surgery with a median age of 57 (34-72) yrs, smoking history 75.9%, alcohol history 72.4% and 82.8% of male. The clinical stage III, IVA and IVB accounted for 24.1%, 48.3% and 27.6%, respectively. The MPR rate was 65.5% (19/29), of which the pCR rate was 41.4% (12/29). R0 resection rate reached 100%. For the per-protocol population, 58.6% pts (17/29) complaint of symptoms included pain, trismus, dysphagic, and speech disorders, all of them reached remission after 2 cycles of neoadjuvant therapy. No delay of surgery occurred. Grade 3-4 adverse events (AEs) occurred in 3 pts including 3.4% G3 leukopenia, 6.9% G3 anemia and 3.4% G4 thrombocytopenia and mostly chemotherapy related. Grade 1-2 AEs included 13.8% anemia, 3.4% thrombocytopenia, 17.2% leukopenia, 13.8% increased aminotransferase, 3.4% increased creatinine, 3.4% hyperglycemia, 27.6% anorexia, 3.4% vomiting, 3.4% diarrhea, 10.3% constipation, 6.9% rash, 100% alopecia and 17.2% fatigue. Conclusions: Neoadjuvant tislelizumab combined with chemotherapy yielded promising MPR and pCR rates with an acceptable safety profile in LA OSCC or OPSCC. Further follow-up is needed to confirm the long-term efficacy. Clinical trial information: ChiCTR2200056354 .