683P Pembrolizumab plus nabpaclitaxe and platinum as first-line treatment in patients with recurrent or metastatic head and neck squamous-cell carcinoma: A prospective phase II study

Abstract

Pembrolizumab plus platinum and fluorouracil is the standard first-line treatment in patients with recurrent/metastatic head and neck squamous-cell carcinoma (R/M HNSCC). The response rate of the regimen was comparable to the EXTREME regimen. There is great need to increase the efficacy of the first-line treatment for patients with R/M HNSCC. Patients with untreated R/M HNSCC of the oropharynx, hypopharynx, larynx or oral cavity and with ≥1 measurable lesion according to RECIST 1.1 were included. Patients received pembro 200mg, nabpaclitaxel 260mg/m2 plus cisplatin 75 mg/m2 on day 1 every 21 days for up to six cycles followed by pembro maintenance therapy until progression or unacceptable toxicity or 35 cycles, whichever occurred first. The primary endpoint was overall response rate (ORR). Secondary endpoints comprised safety, disease control rate (DCR), overall survival (OS) and progression free survival (PFS). From April 30, 2021 until December 15 2021, 20 patients were enrolled. Median age was 59 (range 46-69). There were 11 patients (55%) with distant metastatic disease,7 (35%) with local disease and 2 (10%) with distant and local diseases at enrollment. Three patients (15%) achieved complete response, and two of them had local diseases relapsed after radiotherapy. The ORR was 80% and the DCR was 90%. Median follow-up was 10.0 months, the median PFS was 6.9 months and the median OS was not reached. Myelosuppression was reported in all 20 patients. The most common immune-related AEs were hypothyroidism (40%). One patient (5%) experienced grade 3 immune hypoadrenocorticism. There was no treatment-related adverse event leading to treatment discontinuation.Table: 683PPatient Number20Age, years oldMedian (range)59 (46-69)Gender (male/female)18 / 2ECOG PS011 (55%)19 (45%)Primary tumorhypopharynx9 (45%)larynx6 (30%)oropharynx3 (15%)oral cavity2 (10%)PD-L1 combined positive score< 11 (5%)1-207 (35%)＞2012 (60%) Open table in a new tab Pembrolizumab combined with nabpaclitaxel and platinum shows encouraging antitumor activity accompanied with a manageable side effect profile in untreated R/M HNSCC patients.