153P - Neoadjuvant therapy with tislelizumab plus chemotherapy followed by concurrent chemoradiotherapy in patients with stage IV a nasopharyngeal carcinoma: A single-arm, phase II trial

Background

The effect of comprehensive treatment for locally advanced nasopharyngeal carcinoma (LANPC) is still unsatisfied, especially for stage IVa NPC. 2 or 3 cycles of neoadjuvant therapy may not be enough. Immunotherapy has been reported to benefit patients with LANPC. Therefore, this study investigated the efficacy and safety of four cycles tislelizumab combined with neoadjuvant chemotherapy in treating stage IVa NPC.

Methods

Patients with stage IVa NPC were enrolled and treated with neoadjuvant chemotherapy (gemcitabine, 1000 mg/m2, days 1 and 8, cisplatin, 80 mg/m2, day 1) and tislelizumab (200mg, day 1) every 3 weeks for 4 cycles followed by standard concurrent chemoradiotherapy. The primary endpoint was complete response (CR) rate after neoadjuvant treatment. Secondary endpoints included overall response rate (ORR) after neoadjuvant treatment, disease-free survival, safety and so on.

Results

From February 2022 to June 2022, 25 patients were enrolled at Jiangmen Central Hospital. As of Sep 15^th 2022, the median follow-up time was 124.5 days. Overall, 24 patients were assessed by investigator according to RECIST v1.1 and 1 patient was withdrawn from the trial due to treatment of acute viral parotitis. All the 24 evaluable patients completed protocol-specified 4 cycles of therapy without delaying radiotherapy. 12 patients (50%) achieved CR after neoadjuvant therapy. The ORR of all evaluable patients was 91.7%. 13 (52%) of 25 patients had grade 3-4 treatment-related adverse events. Grade 1-2 immune-related adverse events(irAE) was recorded in 18 patients (72%). There were no grade 3-4 irAEs. Any grade of irAEs included hyperthyroidism, hypothyroidism, rash, and pruritus. A numerically higher CR rate of PD-L1 positive（TC≥1%）patients than PD-L1 negative(TC=0) patients (61% vs 0).

Conclusions

Four cycles tislelizumab in combination with neoadjuvant chemotherapy demonstrated a manageable safety profile and improved clinical response in high-risk LANPC patients. Patients with PD-L1 positive may be associated with favorable response. Long-term survival benefit will be followed continuously in this ongoing trial.

Clinical trial identification

ChiCTR2200056941.

Legal entity responsible for the study

Jiangmen Central Hospital.

Funding

BeiGene (Beijing) Co., Ltd.

Disclosure

All authors have declared no conflicts of interest.