Purpose: Mucosal melanoma is an aggressive malignancy with a poor response to conventional therapies. The efficacy and safety of nivolumab (a programmed death-1 checkpoint inhibitor), alone or combined with ipilimumab (a cytotoxic T-lymphocyte antigen-4 checkpoint inhibitor), have not been reported in this rare melanoma subtype. Patients and Methods: Data were pooled from 889 patients who received nivolumab monotherapy in clinical studies, including phase III trials; 86 (10%) had mucosal melanoma and 665 (75%) had cutaneous melanoma. Data were also pooled for patients who received nivolumab combined with ipilimumab (n = 35, mucosal melanoma; n = 326, cutaneous melanoma). Results: Among patients who received nivolumab monotherapy, median progression-free survival was 3.0 months (95% CI, 2.2 to 5.4 months) and 6.2 months (95% CI, 5.1 to 7.5 months) for mucosal and cutaneous melanoma, with objective response rates of 23.3% (95% CI, 14.8% to 33.6%) and 40.9% (95% CI, 37.1% to 44.7%), respectively. Median progression-free survival in patients treated with nivolumab combined with ipilimumab was 5.9 months (95% CI, 2.8 months to not reached) and 11.7 months (95% CI, 8.9 to 16.7 months) for mucosal and cutaneous melanoma, with objective response rates of 37.1% (95% CI, 21.5% to 55.1%) and 60.4% (95% CI, 54.9% to 65.8%), respectively. For mucosal and cutaneous melanoma, respectively, the incidence of grade 3 or 4 treatment-related adverse events was 8.1% and 12.5% for nivolumab monotherapy and 40.0% and 54.9% for combination therapy. Conclusion: To our knowledge, this is the largest analysis of data for anti–programmed death-1 therapy in mucosal melanoma to date. Nivolumab combined with ipilimumab seemed to have greater efficacy than either agent alone, and although the activity was lower in mucosal melanoma, the safety profile was similar between subtypes.

We evaluated the safety and activity of autologous T cells expressing NY-ESO-1^c259, an affinity-enhanced T-cell receptor (TCR) recognizing an HLA-A2–restricted NY-ESO-1/LAGE1a–derived peptide, in patients with metastatic synovial sarcoma (NY-ESO-1^c259T cells). Confirmed antitumor responses occurred in 50% of patients (6/12) and were characterized by tumor shrinkage over several months. Circulating NY-ESO-1^c259T cells were present postinfusion in all patients and persisted for at least 6 months in all responders. Most of the infused NY-ESO-1^c259T cells exhibited an effector memory phenotype following ex vivo expansion, but the persisting pools comprised largely central memory and stem-cell memory subsets, which remained polyfunctional and showed no evidence of T-cell exhaustion despite persistent tumor burdens. Next-generation sequencing of endogenous TCRs in CD8⁺ NY-ESO-1^c259T cells revealed clonal diversity without contraction over time. These data suggest that regenerative pools of NY-ESO-1^c259T cells produced a continuing supply of effector cells to mediate sustained, clinically meaningful antitumor effects. Significance: Metastatic synovial sarcoma is incurable with standard therapy. We employed engineered T cells targeting NY-ESO-1, and the data suggest that robust, self-regenerating pools of CD8⁺ NY-ESO-1^c259T cells produce a continuing supply of effector cells over several months that mediate clinically meaningful antitumor effects despite prolonged exposure to antigen. Cancer Discov; 8(8); 944–57. ©2018 AACR. See related commentary by Keung and Tawbi, p. 914. This article is highlighted in the In This Issue feature, p. 899

Metastatic Merkel cell carcinoma (mMCC) is a rare, aggressive skin cancer with poor survival.¹ Merkel cell carcinoma (MCC) is associated with Merkel cell polyomavirus infection, UV light exposure, and advanced age; additional risk factors include fair skin and male sex.^1,2 Despite MCC being a chemosensitive disease, durable responses are rare.³ In retrospective studies of first-line chemotherapy in patients with mMCC, median progression-free survival (PFS) was 3.1 to 4.6 months,^4,5 highlighting the need for improved treatment options. Programmed cell death ligand 1 (PD-L1) is expressed on MCC tumor cells and in the MCC tumor microenvironment, indicating a potential role for immune checkpoint inhibitors such as anti–PD-L1 and anti–programmed cell death 1 (PD-1) antibodies.^6-8 Trials involving anti–PD-1/PD-L1 antibodies have shown clinical activity and durable responses in patients with advanced MCC.^9-11 Based on findings from the phase 2 trial of avelumab, an IgG1 anti–PD-L1 monoclonal antibody, in patients with MCC (JAVELIN Merkel 200), avelumab became the first treatment for patients with mMCC to receive approval in the United States, the European Union, and Japan.^11-15 Herein, we report data from an interim analysis of avelumab as first-line treatment in patients with mMCC.

Background Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer associated with poor survival outcomes in patients with distant metastatic disease (mMCC). In an initial analysis from JAVELIN Merkel 200, a phase 2, prospective, open-label, single-arm trial in mMCC, avelumab—a human anti–programmed death-ligand 1 (PD-L1) monoclonal antibody—showed promising efficacy and a safety profile that was generally manageable and tolerable. Here, we report the efficacy of avelumab after ≥1 year of follow-up in patients with distant mMCC that had progressed following prior chemotherapy for metastatic disease. Patients and methods Patients received avelumab 10 mg/kg by 1-h intravenous infusion every 2 weeks until confirmed disease progression, unacceptable toxicity, or withdrawal. The primary endpoint was best overall response. Secondary endpoints included duration of response (DOR), progression-free survival (PFS), and overall survival (OS). Results Patients (N = 88) were followed for a minimum of 12 months. The confirmed objective response rate was 33.0% (95% CI, 23.3%-43.8%; complete response: 11.4%). An estimated 74% of responses lasted ≥1 year, and 72.4% of responses were ongoing at data cutoff. Responses were durable, with the median DOR not yet reached (95% CI, 18.0 months-not estimable), and PFS was prolonged; 1-year PFS and OS rates were 30% (95% CI, 21%-41%) and 52% (95% CI, 41%-62%), respectively. Median OS was 12.9 months (95% CI, 7.5-not estimable). Subgroup analyses suggested a higher probability of response in patients receiving fewer prior lines of systemic therapy, with a lower baseline disease burden, and with PD-L1–positive tumors; however, durable responses occurred irrespective of baseline factors, including tumor Merkel cell polyomavirus status. Conclusions With longer follow-up, avelumab continues to show durable responses and promising survival outcomes in patients with distant mMCC whose disease had progressed after chemotherapy. Trial registration Clinicaltrials.gov identifier: NCT02155647.

Background Cytokine release syndrome (CRS) has been reported after immunologic manipulations, most often through therapeutic monoclonal antibodies. To our knowledge, CRS after radiation therapy (RT) for cancer has not been reported before. The development of unusual clinical signs and symptoms after RT led us to investigate the possibility of CRS after RT and review the medical literature on this topic. Case presentation A 65 year-old man with untreated chronic lymphocytic leukemia and recurrent, metastatic Merkel cell carcinoma undergoing anti-programmed death 1 (PD1) immunotherapy was referred for palliative RT to sites of progressing metastases. Within hours of each weekly dose of RT, he experienced fever, tachycardia, hypotension, rash, dyspnea, and rigors. Based on clinical suspicion for CRS, blood cytokine measurements were performed 1 h after the second and third dose of RT and demonstrated tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) levels approximately ten-fold higher than normal. These were near normal immediately prior to the third dose of RT, and resolved to normal levels 3 weeks after RT. He experienced rapid regression of irradiated tumors, with development of new sites of metastases soon thereafter. A literature review revealed no clinical cases of CRS after RT for cancer. Conclusions RT during anti-PD1 immunotherapy in a patient with underlying immune dysfunction appeared to be the putative mediator of an immune process which yielded significant increases in pro-inflammatory cytokines, and produced the clinical symptoms meeting the definition of grade 3 CRS. This case demonstrates the capability of RT to elicit immune-related adverse events.