A phase II trial of neoadjuvant nivolumab, docetaxel, and cisplatin followed by surgery and radiation therapy for resectable high-grade salivary gland carcinoma.

Abstract

e18061 Background: High-grade resectable salivary gland carcinomas, typically treated with surgery and adjuvant therapies, often recur. This study explores combining an immune checkpoint inhibitor (ICI) with chemotherapy as neoadjuvant therapy to improve outcomes in high-risk, operable cases. Methods: This trial enrolled high-grade SGC patients with clinically positive lymph nodes. Participants received three cycles of nivolumab in conjunction with docetaxel and cisplatin every three weeks. The primary response was assessed three weeks post-treatment, and surgery followed at seven weeks in cases deemed operable. The pathologic outcomes determined the need for adjuvant radiotherapy, administered at 59.4Gy (R0) or 66.0Gy (R1 or R2). The study's primary endpoint was the major pathologic response rate (MPR). We aimed to recruit 50 patients. Herein, we present an interim analysis (NCT05727410). Results: Since November 2022, 19 patients have enrolled; predominantly male (89.5%) with a median age of 62 (range 42-75). Histologic analysis identified various subtypes, primarily salivary duct carcinoma (68.4%). Other histologies included high-grade adenocarcinoma (10.5%), mucoepidermoid carcinoma (10.5%), basaloid squamous cell carcinoma (5.3%), and secretary carcinoma (5.3%). At the time point of analysis, surgery was performed on 16 patients, and 3 patients are still under neoadjuvant therapy. Complete resection (R0) was achieved in 87.5% (n=14) of the cases, with one patient having R1 and another R2 resection. Pathologic analysis showed 12.5% (n=2) achieving pathological complete response and 18.8% (n=3) achieving MPR. Tumor viability varied, with 37.5% (n=6) presenting with 10% to 50% viability and 31.3% (n=5) presenting with 50% or higher viability. A patient with salivary duct carcinoma histology with tumor viability of 20% after neoadjuvant treatment experienced recurrence after 4.1 months from surgery. Notably, throughout the neoadjuvant treatment phase, no patients discontinued due to toxicity or intolerance, indicating a favorable tolerance profile for the combination therapy. An ongoing exploratory biomarker study includes PD-L1 expression and genomic profiling. Conclusions: The preliminary findings of this study demonstrate that the neoadjuvant combination of immune checkpoint inhibitor with chemotherapy significantly reduces tumor burden in salivary gland carcinoma, as evidenced by the high rate of complete resections (R0) and favorable pathologic responses. This treatment strategy not only facilitates surgical outcomes but also exhibits an acceptable safety profile, with no instances of treatment discontinuation due to toxicity or intolerance. These promising results underscore the potential of ICI combination therapy in the management of SGC and warrant further detailed investigations. Clinical trial information: NCT05727410 .