Failure to predict response to immunotherapy (IO) limited its benefit in the treatment of head and neck squamous cell cancer (HNSCC) to 20% of patients or less. Biomarkers including tumor mutational burden (TMB) and programmed death ligand-1 (PD-L1) were evaluated as predictors of response to IO, but the results are inconsistent and with a lack of standardization of their methods. In this retrospective study, TMB and PD-L1 were measured by commercially available methodologies and were correlated to demographics, outcome, and response to PD-1 inhibitors. No correlation was found between TMB and PD-L1 levels. High TMB was associated with smoking and laryngeal primaries. PD-L1 was significantly higher in African Americans, patients with earlier stage tumors, nonsmokers, and nonethanol drinkers. Patients with high TMB fared better in univariate and multivariate survival analysis. No correlation was found between PD-L1 expression and prognosis. There was a statistically significant association between PFS and response to IO and TMB. There was no association between response to ICI and PD-L1 in this study, possibly affected by variations in the reporting method. Further studies are needed to characterize the biomarkers for IO in HNSCC, and this study supports further research into the advancement of TMB in prospective studies.

The role of the microbiome in the development and propagation of head and neck squamous cell cancer (HNSCC) is largely unknown and the surrounding knowledge lags behind what has been discovered related to the microbiome and other malignancies. In this review, the authors performed a structured analysis of the available literature from several databases. The authors discuss the merits and detriments of several studies discussing the microbiome of the structures of the aerodigestive system throughout the development of HNSCC, the role of the microbiome in the development of malignancies (generally and in HNSCC) and clinical applications of the microbiome in HNSCC. Further studies will be needed to adequately describe the relationship between HNSCC and the microbiome, and to push this relationship into a space where it is clinically relevant outside of a research environment.

PARP inhibitors are currently approved for a limited number of cancers and targetable mutations in DNA damage repair (DDR) genes. In this single-institution retrospective study, the profiles of 170 patients with head and neck squamous cell cancer (HNSCC) and available tumor tissue DNA (tDNA) and circulating tumor DNA (ctDNA) results were analyzed for mutations in a set of 18 DDR genes as well as in gene subsets defined by technical and clinical significance. Mutations were correlated with demographic and outcome data. The addition of ctDNA to the standard tDNA analysis contributed to identification of a significantly increased incidence of patients with mutations in one or more genes in each of the study subsets of DDR genes in groups of patients older than 60 years, patients with laryngeal primaries, patients with advanced stage at diagnosis and patients previously treated with chemotherapy and/or radiotherapy. Patients with DDR gene mutations were found to be significantly less likely to have primary tumors within the in oropharynx or HPV-positive disease. Patients with ctDNA mutations in all subsets of DDR genes analyzed had significantly worse overall survival in univariate and adjusted multivariate analysis. This study underscores the utility of ctDNA analysis, alone, and in combination with tDNA, for defining the prevalence and the role of DDR gene mutations in HNSCC. Furthermore, this study fosters research promoting the utilization of PARP inhibitors in HNSCC precision oncology treatments.

Background: Immunotherapy with programmed death receptor-1 (PD-1) inhibitors, as a single agent or in combination with chemotherapy, is the standard first-line treatment for recurrent or metastatic head and neck squamous cell cancer (R/M HNSCC). Unfortunately, there is no established second-line treatment for the many patients who fail immunotherapy. Cetuximab is the only targeted therapy approved in HNSCC but historically has a low response rate of 13%. Objectives: We hypothesize that cetuximab monotherapy following an immune checkpoint inhibitor (ICI) will lead to increased efficacy due to a potential synergistic effect on the antitumor immune response, as a result of activation effects of both treatments on innate and adaptative immune responses. To the authors’ knowledge, this is the only ongoing prospective clinical study that evaluates the combination of cetuximab and ICIs administered sequentially. Methods and analysis: In this non-randomized, open-label, phase II trial, 30 patients with R/M HNSCC who have previously failed or could not tolerate a PD-1 inhibitor as a single agent or in combination with chemotherapy will subsequently be treated with cetuximab monotherapy. Outcomes of interest include overall response rate, duration of response, progression-free survival, overall survival, and treatment toxicity, as well as treatment outcome measured by a patient-reported outcome questionnaire. Saliva and blood will be collected for correlative studies to investigate the immune response status at the end of therapy with an ICI and the effect of cetuximab on the antitumor immune response. The results will be correlated with the response to cetuximab and the time window between the last administration of an ICI and the loading dose of cetuximab. The clinical study is actively recruiting. Ethics: This study was approved by the Wake Forest Comprehensive Cancer Center Institutional Review Board: IRB00065239. Clinical trial registration: This study is registered on ClinicalTrials.gov: NCT04375384.

β-arrestin 2 (ARRB2) is involved in the desensitization and trafficking of G protein-coupled receptors (GPCRs) and plays a critical role in cell proliferation, apoptosis, chemotaxis, and immune response modulation. The role of ARRB2 in the pathogenesis of multiple myeloma (MM) has not been elucidated. This study addressed this question by evaluating the expression of ARRB2 in bone marrow (BM) samples from newly diagnosed MM patients and deriving correlations with key clinical outcomes. In light of recent trends towards the use of immune checkpoint inhibitors across malignancies, the effect of ARRB2 in the regulation of the PD-1/PD-L1 axis was also investigated. The expression of ARRB2 was significantly higher in MM patients resistant to proteosome inhibitor (bortezomib) treatment compared to those who responded. Higher ARRB2 expression in the BM of newly diagnosed MM patients was associated with inferior progression-free survival and overall survival. PD-1 expression was downregulated in CD3 T cells isolated from ARRB2 knockout (KO) mice. Furthermore, knockdown of ARRB2 with siRNA reduced PD-1 expression in murine CD3 T cells and PD-L1 expression in murine myeloid-derived suppressor cells. These findings suggest an important role of ARRB2 in MM pathogenesis, potentially mediated via modulation of immune checkpoints in the tumor microenvironment. Our study provides new evidence that ARRB2 may have non-canonical functions independent of GPCRs with relevance to the understanding of MM pathobiology as well as immunotherapy and checkpoint inhibitor escape/resistance more broadly.

The current standard of care for inoperable stage III non-small cell lung cancer (NSCLC) is concurrent chemotherapy and radiation therapy with consolidation durvalumab. Despite this approach, about 50% of patients will experience disease recurrence, with about half of recurrence events occurring at distant metastatic sites. In this review, the authors performed a structured analysis of the available clinical trial data and literature related to the treatment of this disease. The authors discuss the detriments and merits of several of these trials and explore clinical and preclinical data that contribute to the growing body of literature supporting a future with new approaches, including new techniques in radiation therapy, sequencing, and agents. Upcoming trials may illuminate a path towards better outcomes for patients in this setting.