Despite the success of monotherapies based on blockade of programmed cell death 1 (PD-1) in human melanoma, most patients do not experience durable clinical benefit. Pre-existing T-cell infiltration and/or the presence of PD-L1 in tumours may be used as indicators of clinical response; however, blood-based profiling to understand the mechanisms of PD-1 blockade has not been widely explored. Here we use immune profiling of peripheral blood from patients with stage IV melanoma before and after treatment with the PD-1-targeting antibody pembrolizumab and identify pharmacodynamic changes in circulating exhausted-phenotype CD8 T cells (Tex cells). Most of the patients demonstrated an immunological response to pembrolizumab. Clinical failure in many patients was not solely due to an inability to induce immune reinvigoration, but rather resulted from an imbalance between T-cell reinvigoration and tumour burden. The magnitude of reinvigoration of circulating Tex cells determined in relation to pretreatment tumour burden correlated with clinical response. By focused profiling of a mechanistically relevant circulating T-cell subpopulation calibrated to pretreatment disease burden, we identify a clinically accessible potential on-treatment predictor of response to PD-1 blockade.

Objective To evaluate and validate the proposed 8th edition AJCC system for T and N staging of pancreatic adenocarcinoma. Summary Background Data Investigators have questioned the clinical relevance and reproducibility of previous AJCC staging for pancreatic adenocarcinoma. Methods Prospective databases at Memorial Sloan Kettering (MSK), Massachusetts General Hospital (MGH), and Johns Hopkins Hospital (JHH) were queried for patients who had undergone resection for pancreatic adenocarcinoma. Patients who underwent a margin-negative (R0) resection, and who had previously undergone pathologic review, were included. Patients were staged according to 7th edition AJCC criteria, as well as the proposed 8th edition system that includes different definitions of tumor size (T) and nodal status (N). The dataset was randomly split into training and test sets. Results 2,318 patients were identified who met inclusion criteria. Recursive partitioning on the training set (n=1,551) identified statistically appropriate cutoffs for tumor size (<2.2cm, ≥4.8cm,) and nodal status (no positive nodes, 1–3 positive nodes, ≥4 positive nodes) that supported the proposed 8th edition changes. Median survival in patients staged as T3, N0 by the 7th edition definitions was different between institutions (median Center 1, 24mo; Center 2, 37mo; Center 3, 29mo; p=0.054). This difference was not observed when patients were staged as T3, N0 by 8th edition criteria. Stage, and stage-specific outcome (7th edition), on the test set revealed a predominance of patients (68%) within the IIB subgroup, and a concordance probability estimate (CPE) of 0.57 for stage-specific survival. When assessed with 8th edition criteria, no stage subgroup had a majority of patients, and the CPE was 0.58. Conclusions The proposed 8th edition changes for T and N classification were statistically valid and may allow a more reproducible system of T staging. This system also stratifies patients more evenly across stages without sacrificing prognostic accuracy.

Objective To determine the prognostic significance of histologic type/subtype in a large series of patients with primary resected retroperitoneal sarcoma. Summary Background Data The histologic diversity and rarity of retroperitoneal sarcoma has hampered the ability to predict patient outcome. Methods From a single-institution, prospective database, 675 patients treated surgically for primary, non-metastatic retroperitoneal sarcoma during 1982–2010 were identified and histologic type/subtype was reviewed. Clinicopathologic variables were analyzed for association with disease-specific death (DSD), local recurrence (LR), and distant recurrence (DR). Results Median follow-up for survivors was 7.5 years. The predominant histologies were well-differentiated liposarcoma, dedifferentiated liposarcoma, and leiomyosarcoma. Five-year cumulative incidence of DSD was 31%, and factors independently associated with DSD were R2 resection, resection of ≥3 contiguous organs, and histologic type. Five-year cumulative incidence for LR was 39% and for DR was 24%. R1 resection, age, tumor size, and histologic type were independently associated with LR; size, resection of ≥3 organs, and histologic type were independently associated with DR. Liposarcoma and leiomyosarcoma were associated with late recurrence and DSD (as long as 15 years from diagnosis). For solitary fibrous tumor, local recurrence was uncommon (<10%), but early distant recurrence was common (36% at 5 years). Nomograms were developed to predict DSD, LR, and DR. Conclusions Histologic type/subtype is the most important independent predictor of DSD, LR, and DR in primary retroperitoneal sarcoma. Histology predicts the pattern and incidence of LR and DR and will aid in more accurate patient counseling and selection of patients for adjuvant therapy trials.

Ipilimumab, a monoclonal antibody against cytotoxic T lymphocyte antigen 4 (CTLA-4), has been shown to improve survival in patients with advanced metastatic melanoma. It also enhances immunity to NY-ESO-1, a cancer/testis antigen expressed in a subset of patients with melanoma. To characterize the association between immune response and clinical outcome, we first analyzed NY-ESO-1 serum antibody by ELISA in 144 ipilimumab-treated patients with melanoma and found 22 of 140 (16%) seropositive at baseline and 31 of 144 (22%) seropositive following treatment. These NY-ESO-1-seropositive patients had a greater likelihood of experiencing clinical benefit 24 wk after ipilimumab treatment than NY-ESO-1-seronegative patients (P = 0.02, relative risk = 1.8, two-tailed Fisher test). To understand why some patients with NY-ESO-1 antibody failed to experience clinical benefit, we analyzed NY-ESO-1-specific CD4 + and CD8 + T-cell responses by intracellular multicytokine staining in 20 NY-ESO-1-seropositive patients and found a surprising dissociation between NY-ESO-1 antibody and CD8 responses in some patients. NY-ESO-1-seropositive patients with associated CD8 + T cells experienced more frequent clinical benefit (10 of 13; 77%) than those with undetectable CD8 + T-cell response (one of seven; 14%; P = 0.02; relative risk = 5.4, two-tailed Fisher test), as well as a significant survival advantage (P = 0.01; hazard ratio = 0.2, time-dependent Cox model). Together, our data suggest that integrated NY-ESO-1 immune responses may have predictive value for ipilimumab treatment and argue for prospective studies in patients with established NY-ESO-1 immunity. The current findings provide a strong rationale for the clinical use of modulators of immunosuppression with concurrent approaches to favor tumor antigen-specific immune responses, such as vaccines or adoptive transfer, in patients with cancer.

The prognostic and predictive implications of programmed death-ligand 1 (PD-L1) is unknown in sarcoma. We sought to examine the immune milieu in sarcoma specimens. We evaluated PD-L1 expression by immunohistochemistry (IHC) in sarcoma specimens and quantified tumor infiltrating lymphocytes (TIL). We correlated expression with clinical parameters and outcomes. Fifty sarcoma patients treated at Memorial Sloan Kettering Cancer Center were selected. Using the DAKO PD-L1 IHC assay and archival formalin-fixed paraffin embedded tissue specimens; PD-L1 expression was examined. Macrophage and lymphocyte PD-L1 status was determined qualitatively. TIL was quantified. Associations between PD-L1 expression in tumor, macrophages and lymphocytes, TIL and clinical-pathological characteristics were performed. The median age was 46 years (range, 22 – 76) and 66% of patients were male. Tumor, lymphocyte and macrophage PD-L1 expression was noted in 12%, 30% and 58%, respectively with the highest prevalence in gastrointestinal stromal tumors (GIST) (29%.) Lymphocyte and macrophage infiltration was present in 98% and 90%, respectively. There was no association between clinical features, overall survival and PD-L1 expression in tumor or immune infiltrates. Lymphocyte and macrophage infiltration is common in sarcoma, but PD-L1 tumor expression is uncommon in sarcoma with the highest frequency observed in GIST. There was no association between PD-L1 expression, TIL and clinicopathological features and overall survival, however this is limited by the heterogenous patient sample and minimal death events in the studied cohort.

Background Therapeutic antibodies against programmed death receptor 1 (PD-1) are considered front-line therapy in metastatic melanoma. The efficacy of PD-1 blockade for patients with biologically distinct melanomas arising from acral and mucosal surfaces has not been well described. Methods A multi-institutional retrospective cohort analysis identified adults with advanced acral and mucosal melanoma treated with nivolumab or pembrolizumab as standard clinical practice, via expanded access programs, or published prospective trials. Objective responses were determined utilizing investigator-assessed Response Evaluation Criteria in Solid Tumors (RECIST) 1.1. Progression-free (PFS) and overall survival (OS) were assessed using Kaplan-Meier methods. Results 60 individuals were identified; 25 (42%) with acral and 35 (58%) with mucosal melanoma. Fifty-one (85%) patients had received prior therapy, including 77% with prior ipilimumab. Forty patients (67%) received pembrolizumab at 2mg/kg or 10mg/kg and 20 (33%) received nivolumab at 1mg/kg or 3mg/kg every 2–3 weeks. ORR (95% confidence interval, CI) was 32% (15–54%) in acral and 23% (10–40%) in mucosal melanoma. After a median follow up of 20 months in acral and 10.6 months in mucosal, median PFS was 4.1 months and 3.9 months, respectively. Only two patients (3%) discontinued treatment due to toxicity. Conclusions Response rates to PD-1 blockade in patients with acral and mucosal melanomas were comparable to published rates in cutaneous melanoma and support the routine use of PD-1 blockade in clinical practice. Further investigation is needed to identify the mechanisms of response and resistance to therapy in these subtypes.

BackgroundDespite the rapid adoption of immunotherapies in advanced non–small cell lung cancer (advNSCLC), knowledge gaps remain about their real‐world (rw) performance.MethodsThis retrospective, observational, multicenter analysis used the Flatiron Health deidentified electronic health record‐derived database of rw patients with advNSCLC who received treatment with PD‐1 and/or PD‐L1 (PD‐[L]1) inhibitors before July 1, 2017 (N = 5257) and had ≥6 months of follow‐up. The authors investigated PD‐(L)1 line of treatment and PD‐L1 testing rates and the relationship between overall survival (OS) and rw intermediate endpoints: progression‐free survival (rwPFS), rw time to progression (rwTTP), rw time to next treatment (rwTTNT), and rw time to discontinuation (rwTTD).ResultsFirst‐line PD‐(L)1 inhibitor use increased from 0% (in the third quarter of 2014 [Q3 2014]) to 42% (Q2 2017) over the study period. PD‐L1 testing also increased (from 3% in Q3 2015 to 70% in Q2 2017). The estimated median OS was 9.3 months (95% CI, 8.9‐9.8 months), and the estimated rwPFS was 3.2 months (95% CI, 3.1‐3.3 months). Longer OS and rwPFS were associated with ≥50% PD‐L1 percentage staining results. Correlations (⍴) between OS and intermediate endpoints were ⍴ = 0.75 (95% CI, 0.73‐0.76) for rwPFS and ⍴ = 0.60 (95% CI, 0.57‐0.63) for rwTTP, and, for treatment‐based intermediate endpoints, correlations were ⍴ = 0.60 (95% CI, 0.56‐0.64) for rwTTNT (N = 856) and ⍴ = 0.81 (95% CI, 0.80‐0.82) for rwTTD.ConclusionsThe use of first‐line PD‐(L)1 inhibitors and PD‐L1 testing has substantially increased, with better outcomes for patients who have ≥50% PD‐L1 percentage staining. Intermediate rw tumor‐dynamics estimates were moderately correlated with OS in patients with advNSCLC who received immunotherapy, highlighting the need for optimizing and standardizing rw endpoints to enhance the understanding of patient outcomes outside clinical trials.

A change in the cutoff age in the current AJCC/UICC staging system from 45 years to 55 years would lead to a downstaging of 12% of patients, and would improve the statistical validity of the model. Such a change would be clinically relevant for thousands of patients worldwide by preventing overstaging of patients with low-risk disease while providing a more realistic estimate of prognosis for those who remain high risk.