Tumors can evade immune detection by exploiting inhibitory immune checkpoints such as the programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1) pathway. Antibodies that block this pathway offer a promising new approach to treatment in advanced/metastatic non-small cell lung cancer (NSCLC). A systematic review of the literature was conducted to assess the association of PD-L1 with important patient and disease characteristics, the prognostic significance of PD-L1 expressing NSCLC tumors, and the value of PD-L1 as a predictive biomarker of response to anti-PD-1/PD-L1 treatments in advanced/metastatic NSCLC. A total of 35 eligible studies were selected for analysis. Methods used to determine PD-L1 in NSCLC tissue varied considerably; with different PD-L1 antibodies, antibody detection methods, and staining cut-offs. Immunohistochemistry was the most frequent type of PD-L1 assay. Overall, study evidence did not support an association between PD-L1 expression and gender, age, smoking history, tumor histology (adenocarcinoma vs. squamous cell carcinoma), performance status, pathologic tumor grade or EGFR/KRAS/ALK mutational status. In several studies, high PD-L1 expression was associated with shorter survival compared with low expression. Most evidence indicated that patients with high vs. low PD-L1 expression were more likely to experience treatment benefit with anti-PD-1/PD-L1 agents (nivolumab, pembrolizumab, durvalumab, atezolizumab, and avelumab) in advanced NSCLC. Variability in the methods used to determine PD-L1 expression in NSCLC tissue suggests a need for standardized use of well-validated PD-L1 diagnostic assays. Although considerable research links PD-L1 expression in tumors to shorter survival in advanced/metastatic NSCLC, its use as a prognostic factor requires more study. As studies of anti-PD-1/PD-L1 agents continue, PD-L1 is likely to play an important role as a predictive biomarker for selecting patients deriving most benefit from anti-PD-1/PD-L1 monotherapy and directing patients with lower levels of tumor PD-L1 expression (with a high unmet medical need), to alternative treatments, such as combination immunotherapies.

This single-institution phase II study was performed to estimate the response rate to lapatinib in neurofibromatosis type 2 (NF2) patients with progressive vestibular schwannoma (VS). Twenty-one eligible patients were enrolled. Brain and spine MRIs, including 3-dimensional volumetric tumor analysis, and audiograms were performed once at baseline and again every 12 weeks. The primary response end point was evaluable in 17 patients and defined as ≥15% decrease in VS volume. Hearing was evaluable as a secondary end point in 13 patients, with responses defined as an improvement in the pure tone average of at least 10 dB  or a statistically significant increase in word recognition scores. Four of 17 evaluable patients experienced an objective volumetric response (23.5%; 95% confidence interval [CI], 10%-47%), with median time to response of 4.5 months (range, 3-12). In responders, reduction in VS volumes ranged from -15.7% to -23.9%. Four of 13 patients evaluable for hearing met hearing criteria for response (30.8%; 95% CI, 13%-58%). One sustained response exceeded 9 months in duration. Median time to overall progression (ie, volumetric progression or hearing loss) was 14 months. The estimated overall progression-free survival and volumetric progression-free survival at 12 months were 64.2% (95% CI, 36.9%-82.1%) and 70.6% (95% CI, 43.1%-86.6%), respectively. Toxicity was generally minor, and no permanent dose modifications were required. Lapatinib carries minor toxicity and has objective activity in NF2 patients with progressive VS, including volumetric and hearing responses. Future studies could explore combination therapy with other molecular targeted agents such as bevacizumab.

Anti-programmed cell death-1 and anti-programmed cell death ligand-1 (PD-L1) monotherapies have shown promising clinical activity in advanced, refractory non-small-cell lung cancer (NSCLC), but antitumor activity appears to be greater in patients with PD-L1(+) tumors compared with patients harboring PD-L1(-) tumors. Combining the anti-PD-L1 antibody durvalumab and the anti-cytotoxic T-lymphocyte antigen 4 antibody tremelimumab offers the potential for antitumor activity in patients with advanced NSCLC, regardless of PD-L1 tumor status. ARCTIC (NCT02352948) is a global, phase III, randomized, open-label multicenter study in patients with advanced NSCLC assessing the safety and clinical activity of durvalumab versus standard of care (SoC; erlotinib, gemcitabine, or vinorelbine) in patients with PD-L1(+) tumors (≥25% of tumor cells with membrane staining using VENTANA PD-L1 [SP263] CDx Assay) (Sub-study A) and the combination of durvalumab + tremelimumab or either agent as monotherapy versus SoC in patients with PD-L1(-) tumors (Sub-study B). Eligible patients are those with locally advanced or metastatic NSCLC (Stage IIIB/IV), without epidermal growth factor receptor tyrosine kinase activating mutations or anaplastic lymphoma kinase rearrangements, who have received at least 2 prior systemic regimens, including 1 platinum-based chemotherapy regimen. Co-primary endpoints are progression-free survival and overall survival. Secondary endpoints include the proportion of patients alive at 12 months, objective response rate, duration of response, progression-free survival at 6 and 12 months, safety and tolerability, pharmacokinetics, immunogenicity, and quality of life. The exploratory endpoints will assess potential biomarkers of treatment response. Recruitment started in January 2015 and is ongoing.