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Abstract
Background Patients with recurrent or metastatic squamous-cell carcinoma of the head
and neck after platinum chemotherapy have a very poor prognosis and limited therapeutic
options. Nivolumab, an anti-programmed death 1 (PD-1) monoclonal antibody, was assessed
as treatment for this condition. Methods In this randomized, open-label, phase 3 trial,
we assigned, in a 2:1 ratio, 361 patients with recurrent squamous-cell carcinoma of
the head and neck whose disease had progressed within 6 months after platinum-based
chemotherapy to receive nivolumab (at a dose of 3 mg per kilogram of body weight)
every 2 weeks or standard, single-agent systemic therapy (methotrexate, docetaxel,
or cetuximab). The primary end point was overall survival. Additional end points included
progression-free survival, rate of objective response, safety, and patient-reported
quality of life. Results The median overall survival was 7.5 months (95% confidence
interval [CI], 5.5 to 9.1) in the nivolumab group versus 5.1 months (95% CI, 4.0 to
6.0) in the group that received standard therapy. Overall survival was significantly
longer with nivolumab than with standard therapy (hazard ratio for death, 0.70; 97.73%
CI, 0.51 to 0.96; P=0.01), and the estimates of the 1-year survival rate were approximately
19 percentage points higher with nivolumab than with standard therapy (36.0% vs. 16.6%).
The median progression-free survival was 2.0 months (95% CI, 1.9 to 2.1) with nivolumab
versus 2.3 months (95% CI, 1.9 to 3.1) with standard therapy (hazard ratio for disease
progression or death, 0.89; 95% CI, 0.70 to 1.13; P=0.32). The rate of progression-free
survival at 6 months was 19.7% with nivolumab versus 9.9% with standard therapy. The
response rate was 13.3% in the nivolumab group versus 5.8% in the standard-therapy
group. Treatment-related adverse events of grade 3 or 4 occurred in 13.1% of the patients
in the nivolumab group versus 35.1% of those in the standard-therapy group. Physical,
role, and social functioning was stable in the nivolumab group, whereas it was meaningfully
worse in the standard-therapy group. Conclusions Among patients with platinum-refractory,
recurrent squamous-cell carcinoma of the head and neck, treatment with nivolumab resulted
in longer overall survival than treatment with standard, single-agent therapy. (Funded
by Bristol-Myers Squibb; CheckMate 141 ClinicalTrials.gov number, NCT02105636 .).
Many cancer types, including head and neck cancers (HNC), express programmed death ligand 1 (PD-L1). Interaction between PD-L1 and its receptor, programmed death 1 (PD-1), inhibits the function of activated T cells and results in an immunosuppressive microenvironment, but the stimuli that induce PD-L1 expression are not well characterized. Interferon gamma (IFNγ) and the epidermal growth factor receptor (EGFR) utilize Janus kinase 2 (JAK2) as a common signaling node to transmit tumor cell-mediated extrinsic or intrinsic signals, respectively. In this study, we investigated the mechanism by which these factors upregulate PD-L1 expression in HNC cells in the context of JAK/STAT pathway activation, Th1 inflammation, and HPV status. We found that wild-type, overexpressed EGFR significantly correlated with JAK2 and PD-L1 expression in a large cohort of HNC specimens. Furthermore, PD-L1 expression was induced in an EGFR- and JAK2/STAT1-dependent manner, and specific JAK2 inhibition prevented PD-L1 upregulation in tumor cells and enhanced their immunogenicity. Collectively, our findings suggest a novel role for JAK2/STAT1 in EGFR-mediated immune evasion, and therapies targeting this signaling axis may be beneficial to block PD-L1 upregulation found in a large subset of HNC tumors.
Immune rejection of tumors is mediated by IFNγ production and T-cell cytolytic activity. These processes are impeded by PD-1, a coinhibitory molecule expressed on T cells that is elevated in tumor-infiltrating lymphocytes (TIL). PD-1 elevation may reflect T-cell exhaustion marked by decreased proliferation, production of type I cytokines, and poor cytolytic activity. Although anti-PD-1 antibodies enhance IFNγ secretion after stimulation of the T-cell receptor (TCR), the mechanistic link between PD-1 and its effects on T-cell help (Tc1/Th1 skewing) remains unclear. In prospectively collected cancer tissues, we found that TIL exhibited dampened Tc1/Th1 skewing and activation compared with peripheral blood lymphocytes (PBL). When PD-1 bound its ligand PD-L1, we observed a marked suppression of critical TCR target genes and Th1 cytokines. Conversely, PD-1 blockade reversed these suppressive effects of PD-1:PD-L1 ligation. We also found that the TCR-regulated phosphatase SHP-2 was expressed higher in TIL than in PBL, tightly correlating with PD-1 expression and negative regulation of TCR target genes. Overall, these results defined a PD-1/SHP-2/STAT1/T-bet signaling axis mediating the suppressive effects of PD-1 on Th1 immunity at tumor sites. Our findings argue that PD-1 or SHP-2 blockade will be sufficient to restore robust Th1 immunity and T-cell activation and thereby reverse immunosuppression in the tumor microenvironment.
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