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BackgroundPD-1 and PD-L1 inhibitors have emerged as promising treatments for patients with head and neck squamous cell carcinoma (HNSCC).MethodsSystematic review and meta-analysis of PD-1 and PD-L1 inhibitors in HNSCC. Outcomes: median overall survival (mOS), median progression-free survival (mPFS), Response Evaluation Criteria in Solid Tumors (RECIST) and treatment-related adverse events (TRAEs).ResultsEleven trials reported data on 1088 patients (mean age: 59.9 years, range: 18-90). The total mOS was 7.97 months (range: 6.0-16.5). Mean mPFS for all studies was 2.84 months (range: 1.9-6.5). PD-1 inhibitors had a lower rate of RECIST Progressive Disease than PD-L1 inhibitors (42.61%, 95% confidence interval [CI]: 36.29-49.06 vs. 56.79%, 95% CI: 49.18-64.19, P < 0.001). The rate of TRAEs of any grade (62.7%, 95% CI: 59.8-65.6) did not differ.ConclusionsMeta-analysis shows the efficacy of PD-1 and PD-L1 inhibitors in HNSCC and suggests a possible difference in certain RECIST criterion between PD-1 and PD-L1 inhibitors. Future work to investigate the clinical significance of these findings is warranted.

PurposeInvestigate whether adjuvant everolimus, an mTOR inhibitor, improves progression-free survival (PFS) in advanced-stage head and neck squamous cell carcinoma (HNSCC) and provide outcomes related to correlative biological factors associated with disease control.Patients and methodsThis was a prospective, randomized, double-blind phase II trial of patients with advanced-stage HNSCC from 13 institutions who were confirmed disease-free post-definitive therapy and enrolled between December 2010 and March 2015. Patients received adjuvant everolimus or placebo daily (10 mg, oral) for a maximum of 1 year. p16 IHC as a surrogate marker for human papillomavirus infection and whole-exome sequencing were performed. Cox proportional hazard models estimated hazard rates. Log-rank tests evaluated differences in survival. The primary endpoint was PFS. Secondary endpoints and objectives included overall survival (OS) and toxicity assessment.Results52 patients [median (range) age, 58 (37-76) years; 43 men (83%), 9 women (17%)] were randomized to placebo (n = 24) or everolimus (n = 28). PFS favored everolimus, but was not significant [log-rank P = 0.093; HR = 0.44; 95% confidence interval (CI), 0.17-1.17]. There was no difference in OS (P = 0.29; HR = 0.57; 95% CI, 0.20-16.2). Everolimus resulted in significant improvement in PFS for p16-negative patients (n = 31; P = 0.031; HR = 0.26; 95% CI, 0.07-0.97), although subgroup analysis showed no difference for p16-positive patients (n = 21; P = 0.93). Further, PFS was significantly higher in TP53-mutated (TP53mut) patients treated with everolimus compared with placebo (log-rank P = 0.027; HR = 0.24; 95% CI, 0.06-0.95). No treatment difference was seen in patients with TP53 wild-type tumors (P = 0.79).Conclusionsp16-negative and TP53mut patients may benefit from adjuvant treatment with everolimus.

PurposeWe studied the impact of mTOR signaling inhibition with rapamycin in head and neck squamous cell carcinoma (HNSCC) in the neoadjuvant setting. The goals were to evaluate the mTOR pathway as a therapeutic target for patients with advanced HNSCC, and the clinical safety, antitumor, and molecular activity of rapamycin administration on HNSCC.Patients and methodsPatients with untreated stage II-IVA HNSCC received rapamycin for 21 days (day 1, 15 mg; days 2-12, 5 mg) prior to definitive treatment with surgery or chemoradiation. Treatment responses were assessed clinically and radiographically with CT and FDG-PET. Pre- and posttreatment biopsies and blood were obtained for toxicity, immune monitoring, and IHC assessment of mTOR signaling, as well as exome sequencing.ResultsSixteen patients (eight oral cavity, eight oropharyngeal) completed rapamycin and definitive treatment. Half of patients were p16 positive. One patient had a pathologic complete response and four (25%) patients met RECIST criteria for response (1 CR, 3 PR, 12 SD). Treatment was well tolerated with no grade 4 or unexpected toxicities. No significant immune suppression was observed. Downstream mTOR signaling was downregulated in tumor tissues as measured by phosphorylation of S6 (P < 0.0001), AKT (P < 0.0001), and 4EBP (P = 0.0361), with a significant compensatory increase in phosphorylated ERK in most patients (P < 0.001). Ki67 was reduced in tumor biopsies in all patients (P = 0.013).ConclusionsRapamycin treatment was well tolerated, reduced mTOR signaling and tumor growth, and resulted in significant clinical responses despite the brief treatment duration, thus supporting the potential role of mTOR inhibitors in treatment regimens for HNSCC.