Nivolumab with or without ipilimumab in patients with recurrent or metastatic cervical cancer (CheckMate 358): a phase 1-2, open-label, multicohort trial

BACKGROUND

In preliminary findings from the recurrent or metastatic cervical cancer cohort of CheckMate 358, nivolumab showed durable anti-tumour responses, and the combination of nivolumab plus ipilimumab showed promising clinical activity. Here, we report long-term outcomes from this cohort.

METHODS

CheckMate 358 was a phase 1-2, open-label, multicohort trial. The metastatic cervical cancer cohort enrolled patients from 30 hospitals and cancer centres across ten countries. Female patients aged 18 years or older with a histologically confirmed diagnosis of squamous cell carcinoma of the cervix with recurrent or metastatic disease, an Eastern Cooperative Oncology Group performance status of 0 or 1, and up to two previous systemic therapies were enrolled into the nivolumab 240 mg every 2 weeks group, the randomised groups (nivolumab 3 mg/kg every 2 weeks plus ipilimumab 1 mg/kg every 6 weeks [NIVO3 plus IPI1] or nivolumab 1 mg/kg every 3 weeks plus ipilimumab 3 mg/kg every 3 weeks for four cycles then nivolumab 240 mg every 2 weeks [NIVO1 plus IPI3]), or the NIVO1 plus IPI3 expansion group. All doses were given intravenously. Patients were randomly assigned (1:1) to NIVO3 plus IPI1 or NIVO1 plus IPI3 via an interactive voice response system. Treatment continued until disease progression, unacceptable toxicity, or consent withdrawal, or for up to 24 months. The primary endpoint was investigator-assessed objective response rate. Anti-tumour activity and safety were analysed in all treated patients. This study is registered with ClinicalTrials.gov (NCT02488759) and is now completed.

FINDINGS

Between October, 2015, and March, 2020, 193 patients were recruited in the recurrent or metastatic cervical cancer cohort of CheckMate 358, of whom 176 were treated. 19 patients received nivolumab monotherapy, 45 received NIVO3 plus IPI1, and 112 received NIVO1 plus IPI3 (45 in the randomised group and 67 in the expansion group). Median follow-up times were 19·9 months (IQR 8·2-44·8) with nivolumab, 12·6 months (7·8-37·1) with NIVO3 plus IPI1, and 16·7 months (7·2-27·5) with pooled NIVO1 plus IPI3. Objective response rates were 26% (95% CI 9-51; five of 19 patients) with nivolumab, 31% (18-47; 14 of 45 patients) with NIVO3 plus IPI1, 40% (26-56; 18 of 45 patients) with randomised NIVO1 plus IPI3, and 38% (29-48; 43 of 112 patients) with pooled NIVO1 plus IPI3. The most common grade 3-4 treatment-related adverse events were diarrhoea, hepatic cytolysis, hyponatraemia, pneumonitis, and syncope (one [5%] patient each; nivolumab group), diarrhoea, increased gamma-glutamyl transferase, increased lipase, and vomiting (two [4%] patients each; NIVO3 plus IPI1 group), and increased lipase (nine [8%] patients) and anaemia (seven [6%] patients; pooled NIVO1 plus IPI3 group). Serious treatment-related adverse events were reported in three (16%) patients in the nivolumab group, 12 (27%) patients in the NIVO3 plus IPI1 group, and 47 (42%) patients in the pooled NIVO1 plus IPI3 group. There was one treatment-related death due to immune-mediated colitis in the NIVO1 plus IPI3 group.

INTERPRETATION

Nivolumab monotherapy and nivolumab plus ipilimumab combination therapy showed promise in the CheckMate 358 study as potential treatment options for recurrent or metastatic cervical cancer. Future randomised controlled trials of nivolumab plus ipilimumab or other dual immunotherapy regimens are warranted to confirm treatment benefit in this patient population.

FUNDING

Bristol Myers Squibb and Ono Pharmaceutical.

Nivolumab + Tacrolimus + Prednisone ± Ipilimumab for Kidney Transplant Recipients With Advanced Cutaneous Cancers

PURPOSE

Cancer-related mortality rates among kidney transplant recipients (KTR) are high, but these patients have largely been excluded from trials of immune checkpoint inhibitors because of immunosuppression and risk of treatment-related allograft loss (TRAL). We conducted a prospective clinical trial testing nivolumab (NIVO) + tacrolimus (TACRO) + prednisone (PRED) ± ipilimumab (IPI) in KTR with advanced cutaneous cancers.

METHODS

Adult KTR with advanced melanoma or basal, cutaneous squamous, or Merkel cell carcinomas were eligible. Immunosuppression was standardized to TACRO (serum trough 2-5 ng/mL) + PRED 5 mg once daily. Patients then received NIVO 480 mg IV once every 4 weeks. The primary composite end point was partial or complete (tumor) response (CR) or stable disease per RECIST v1.1 without allograft loss at 16W. Patients with progressive disease (PD) could receive IPI 1 mg/kg IV + NIVO 3 mg/kg once every 3 weeks × 4 followed by NIVO. Donor-derived cell-free DNA (dd-cfDNA) levels were measured approximately once every 2 weeks as a potential predictor of allograft rejection.

RESULTS

Among eight evaluable patients, none met the trial's primary end point. All eight patients experienced PD on NIVO + TACRO + PRED; TRAL occurred in one patient. Six patients then received IPI + NIVO + TACRO + PRED. Best overall responses: two CR (one with TRAL) and four PD (one with TRAL). In total, 7 of 8 pre-NIVO tumor biopsies contained a paucity of infiltrating immune cells. In total, 2 of 5 on-NIVO biopsies demonstrated moderate immune infiltrates; both patients later experienced a CR to IPI + NIVO. In 2 of 3 patients with TRAL, dd-cfDNA elevations occurred 10 and 15 days before increases in serum creatinine.

CONCLUSION

In most KTR with advanced skin cancer, TACRO + PRED provides insufficient allograft protection and compromises immune-mediated tumor regression after administration of NIVO ± IPI. Elevated dd-cfDNA levels can signal treatment-related allograft rejection earlier than rises in serum creatinine.

Comparing anti-tumor and anti-self immunity in a patient with melanoma receiving immune checkpoint blockade

BACKGROUND

Tumor regression following immune checkpoint blockade (ICB) is often associated with immune-related adverse events (irAEs), marked by inflammation in non-cancerous tissues. This study was undertaken to investigate the functional relationship between anti-tumor and anti-self immunity, to facilitate irAE management while promoting anti-tumor immunity.

METHODS

Multiple biopsies from tumor and inflamed tissues were collected from a patient with melanoma experiencing both tumor regression and irAEs on ICB, who underwent rapid autopsy. Immune cells infiltrating melanoma lesions and inflamed normal tissues were subjected to gene expression profiling with multiplex qRT-PCR for 122 candidate genes. Subsequently, immunohistochemistry was conducted to assess the expression of 14 candidate markers of immune cell subsets and checkpoints. TCR-beta sequencing was used to explore T cell clonal repertoires across specimens.

RESULTS

While genes involved in MHC I/II antigen presentation, IFN signaling, innate immunity and immunosuppression were abundantly expressed across specimens, irAE tissues over-expressed certain genes associated with immunosuppression (CSF1R, IL10RA, IL27/EBI3, FOXP3, KLRG1, SOCS1, TGFB1), including those in the COX-2/PGE2 pathway (IL1B, PTGER1/EP1 and PTGER4/EP4). Immunohistochemistry revealed similar proportions of immunosuppressive cell subsets and checkpoint molecules across samples. TCRseq did not indicate common TCR repertoires across tumor and inflammation sites, arguing against shared antigen recognition between anti-tumor and anti-self immunity in this patient.

CONCLUSIONS

This comprehensive study of a single patient with melanoma experiencing both tumor regression and irAEs on ICB explores the immune landscape across these tissues, revealing similarities between anti-tumor and anti-self immunity. Further, it highlights expression of the COX-2/PGE2 pathway, which is known to be immunosuppressive and potentially mediates ICB resistance. Ongoing clinical trials of COX-2/PGE2 pathway inhibitors targeting the major COX-2 inducer IL-1B, COX-2 itself, or the PGE2 receptors EP2 and EP4 present new opportunities to promote anti-tumor activity, but may also have the potential to enhance the severity of ICB-induced irAEs.

Circulating cancer-specific CD8 T cell frequency is associated with response to PD-1 blockade in Merkel cell carcinoma

Understanding cancer immunobiology has been hampered by difficulty identifying cancer-specific T cells. Merkel cell polyomavirus (MCPyV) causes most Merkel cell carcinomas (MCCs). All patients with virus-driven MCC express MCPyV oncoproteins, facilitating identification of virus (cancer)-specific T cells. We studied MCPyV-specific T cells from 27 patients with MCC using MCPyV peptide-HLA-I multimers, 26-color flow cytometry, single-cell transcriptomics, and T cell receptor (TCR) sequencing. In a prospective clinical trial, higher circulating MCPyV-specific CD8 T cell frequency before anti-PD-1 treatment was strongly associated with 2-year recurrence-free survival (75% if detectable, 0% if undetectable, p = 0.0018; ClinicalTrial.gov: NCT02488759). Intratumorally, such T cells were typically present, but their frequency did not significantly associate with response. Circulating MCPyV-specific CD8 T cells had increased stem/memory and decreased exhaustion signatures relative to their intratumoral counterparts. These results suggest that cancer-specific CD8 T cells in the blood may play a role in anti-PD-1 responses. Thus, strategies that augment their number or mobilize them into tumors could improve outcomes.

T antigen-specific CD8+ T cells associate with PD-1 blockade response in virus-positive Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a highly immunogenic skin cancer primarily induced by Merkel cell polyomavirus, which is driven by the expression of the oncogenic T antigens (T-Ags). Blockade of the programmed cell death protein-1 (PD-1) pathway has shown remarkable response rates, but evidence for therapy-associated T-Ag-specific immune response and therapeutic strategies for the nonresponding fraction are both limited. We tracked T-Ag-reactive CD8+ T cells in peripheral blood of 26 MCC patients under anti-PD1 therapy, using DNA-barcoded pMHC multimers, displaying all peptides from the predicted HLA ligandome of the oncoproteins, covering 33 class I haplotypes. We observed a broad T cell recognition of T-Ags, including identification of 20 T-Ag-derived epitopes we believe to be novel. Broadening of the T-Ag recognition profile and increased T cell frequencies during therapy were strongly associated with clinical response and prolonged progression-free survival. T-Ag-specific T cells could be further boosted and expanded directly from peripheral blood using artificial antigen-presenting scaffolds, even in patients with no detectable T-Ag-specific T cells. These T cells provided strong tumor-rejection capacity while retaining a favorable phenotype for adoptive cell transfer. These findings demonstrate that T-Ag-specific T cells are associated with the clinical outcome to PD-1 blockade and that Ag-presenting scaffolds can be used to boost such responses.

Neoadjuvant immune checkpoint blockade: A window of opportunity to advance cancer immunotherapy

Among new treatment approaches for patients with cancer, few have accelerated as quickly as neoadjuvant immune checkpoint blockade (ICB). Neoadjuvant cancer therapy is administered before curative-intent surgery in treatment-naïve patients. Conventional neoadjuvant chemotherapy and radiotherapy are primarily intended to reduce tumor size, improving surgical resectability. However, recent scientific evidence outlined here suggests that neoadjuvant immunotherapy can expand and transcriptionally modify tumor-specific T cell clones to enhance both intratumoral and systemic anti-tumor immunity. It further offers a unique "window of opportunity" to explore mechanisms and identify novel biomarkers of ICB response and resistance, opening possibilities for refining long-term clinical outcome predictions and developing new, more highly effective ICB combination therapies. Here, we examine advances in clinical and scientific knowledge gleaned from studies in select cancers and describe emerging key principles relevant to neoadjuvant ICB across many cancer types.

Combinatorial biomarker for predicting outcomes to anti-PD-1 therapy in patients with metastatic clear cell renal cell carcinoma

With a rapidly developing immunotherapeutic landscape for patients with metastatic clear cell renal cell carcinoma, biomarkers of efficacy are highly desirable to guide treatment strategy. Hematoxylin and eosin (H&E)-stained slides are inexpensive and widely available in pathology laboratories, including in resource-poor settings. Here, H&E scoring of tumor-infiltrating immune cells (TILplus) in pre-treatment tumor specimens using light microscopy is associated with improved overall survival (OS) in three independent cohorts of patients receiving immune checkpoint blockade. Necrosis score alone does not associate with OS; however, necrosis modifies the predictive effect of TILplus, a finding that has broad translational relevance for tissue-based biomarker development. PBRM1 mutational status is combined with H&E scores to further refine outcome predictions (OS, p = 0.007, and objective response, p = 0.04). These findings bring H&E assessment to the fore for biomarker development in future prospective, randomized trials, and emerging multi-omics classifiers.

Five-Year Clinical Outcomes after Neoadjuvant Nivolumab in Resectable Non-Small Cell Lung Cancer

PURPOSE

Neoadjuvant anti-PD-1 therapy has shown promise for resectable non-small cell lung cancer (NSCLC). We reported the first phase I/II trial of neoadjuvant nivolumab in resectable NSCLC, finding it to be safe and feasible with encouraging major pathological responses (MPR). We now present 5-year clinical outcomes from this trial, representing to our knowledge, the longest follow-up data for neoadjuvant anti-PD-1 in any cancer type.

PATIENTS AND METHODS

Two doses of nivolumab (3 mg/kg) were administered for 4 weeks before surgery to 21 patients with Stage I-IIIA NSCLC. 5-year recurrence-free survival (RFS), overall survival (OS), and associations with MPR and PD-L1, were evaluated.

RESULTS

With a median follow-up of 63 months, 5-year RFS and OS rates were 60% and 80%, respectively. The presence of MPR and pre-treatment tumor PD-L1 positivity (TPS ≥1%) each trended toward favorable RFS; HR, 0.61 [95% confidence interval (CI), 0.15-2.44] and HR, 0.36 (95% CI, 0.07-1.85), respectively. At 5-year follow-up, 8 of 9 (89%) patients with MPR were alive and disease-free. There were no cancer-related deaths among patients with MPR. In contrast, 6/11 patients without MPR experienced tumor relapse, and 3 died.

CONCLUSIONS

Five-year clinical outcomes for neoadjuvant nivolumab in resectable NSCLC compare favorably with historical outcomes. MPR and PD-L1 positivity trended toward improved RFS, though definitive conclusions are limited by cohort size.

Survival, Durable Tumor Remission, and Long-Term Safety in Patients With Advanced Melanoma Receiving Nivolumab

PURPOSE

Programmed cell death 1 (PD-1) is an inhibitory receptor expressed by activated T cells that downmodulates effector functions and limits the generation of immune memory. PD-1 blockade can mediate tumor regression in a substantial proportion of patients with melanoma, but it is not known whether this is associated with extended survival or maintenance of response after treatment is discontinued.

PATIENTS AND METHODS

Patients with advanced melanoma (N = 107) enrolled between 2008 and 2012 received intravenous nivolumab in an outpatient setting every 2 weeks for up to 96 weeks and were observed for overall survival, long-term safety, and response duration after treatment discontinuation.

RESULTS

Median overall survival in nivolumab-treated patients (62% with two to five prior systemic therapies) was 16.8 months, and 1- and 2-year survival rates were 62% and 43%, respectively. Among 33 patients with objective tumor regressions (31%), the Kaplan-Meier estimated median response duration was 2 years. Seventeen patients discontinued therapy for reasons other than disease progression, and 12 (71%) of 17 maintained responses off-therapy for at least 16 weeks (range, 16 to 56+ weeks). Objective response and toxicity rates were similar to those reported previously; in an extended analysis of all 306 patients treated on this trial (including those with other cancer types), exposure-adjusted toxicity rates were not cumulative.

CONCLUSION

Overall survival following nivolumab treatment in patients with advanced treatment-refractory melanoma compares favorably with that in literature studies of similar patient populations. Responses were durable and persisted after drug discontinuation. Long-term safety was acceptable. Ongoing randomized clinical trials will further assess the impact of nivolumab therapy on overall survival in patients with metastatic melanoma.

Phase I Study of Single-Agent Anti-Programmed Death-1 (MDX-1106) in Refractory Solid Tumors: Safety, Clinical Activity, Pharmacodynamics, and Immunologic Correlates

PURPOSE

Programmed death-1 (PD-1), an inhibitory receptor expressed on activated T cells, may suppress antitumor immunity. This phase I study sought to determine the safety and tolerability of anti-PD-1 blockade in patients with treatment-refractory solid tumors and to preliminarily assess antitumor activity, pharmacodynamics, and immunologic correlates.

PATIENTS AND METHODS

Thirty-nine patients with advanced metastatic melanoma, colorectal cancer (CRC), castrate-resistant prostate cancer, non-small-cell lung cancer (NSCLC), or renal cell carcinoma (RCC) received a single intravenous infusion of anti-PD-1 (MDX-1106) in dose-escalating six-patient cohorts at 0.3, 1, 3, or 10 mg/kg, followed by a 15-patient expansion cohort at 10 mg/kg. Patients with evidence of clinical benefit at 3 months were eligible for repeated therapy.

RESULTS

Anti-PD-1 was well tolerated: one serious adverse event, inflammatory colitis, was observed in a patient with melanoma who received five doses at 1 mg/kg. One durable complete response (CRC) and two partial responses (PRs; melanoma, RCC) were seen. Two additional patients (melanoma, NSCLC) had significant lesional tumor regressions not meeting PR criteria. The serum half-life of anti-PD-1 was 12 to 20 days. However, pharmacodynamics indicated a sustained mean occupancy of > 70% of PD-1 molecules on circulating T cells ≥ 2 months following infusion, regardless of dose. In nine patients examined, tumor cell surface B7-H1 expression appeared to correlate with the likelihood of response to treatment.

CONCLUSION

Blocking the PD-1 immune checkpoint with intermittent antibody dosing is well tolerated and associated with evidence of antitumor activity. Exploration of alternative dosing regimens and combinatorial therapies with vaccines, targeted therapies, and/or other checkpoint inhibitors is warranted.

Proceedings From the ASCO/College of American Pathologists Immune Checkpoint Inhibitor Predictive Biomarker Summit

PURPOSE

Immune checkpoint inhibition (ICI) therapy represents one of the great advances in the field of oncology, highlighted by the Nobel Prize in 2018. Multiple predictive biomarkers for ICI benefit have been proposed. These include assessment of programmed death ligand-1 expression by immunohistochemistry, and determination of mutational genotype (microsatellite instability or mismatch repair deficiency or tumor mutational burden) as a reflection of neoantigen expression. However, deployment of these assays has been challenging for oncologists and pathologists alike.

METHODS

To address these issues, ASCO and the College of American Pathologists convened a virtual Predictive Factor Summit from September 14 to 15, 2021. Representatives from the academic community, US Food and Drug Administration, Centers for Medicare and Medicaid Services, National Institutes of Health, health insurance organizations, pharmaceutical companies, in vitro diagnostics manufacturers, and patient advocate organizations presented state-of-the-art predictive factors for ICI, associated problems, and possible solutions.

RESULTS

The Summit provided an overview of the challenges and opportunities for improvement in assay execution, interpretation, and clinical applications of programmed death ligand-1, microsatellite instability-high or mismatch repair deficient, and tumor mutational burden-high for ICI therapies, as well as issues related to regulation, reimbursement, and next-generation ICI biomarker development.

CONCLUSION

The Summit concluded with a plan to generate a joint ASCO/College of American Pathologists strategy for consideration of future research in each of these areas to improve tumor biomarker tests for ICI therapy.

Analysis of multispectral imaging with the AstroPath platform informs efficacy of PD-1 blockade

Next-generation tissue-based biomarkers for immunotherapy will likely include the simultaneous analysis of multiple cell types and their spatial interactions, as well as distinct expression patterns of immunoregulatory molecules. Here, we introduce a comprehensive platform for multispectral imaging and mapping of multiple parameters in tumor tissue sections with high-fidelity single-cell resolution. Image analysis and data handling components were drawn from the field of astronomy. Using this "AstroPath" whole-slide platform and only six markers, we identified key features in pretreatment melanoma specimens that predicted response to anti-programmed cell death-1 (PD-1)-based therapy, including CD163⁺PD-L1^- myeloid cells and CD8⁺FoxP3⁺PD-1^low/mid T cells. These features were combined to stratify long-term survival after anti-PD-1 blockade. This signature was validated in an independent cohort of patients with melanoma from a different institution.

Analysis of multispectral imaging with the AstroPath platform informs efficacy of PD-1 blockade

Next-generation tissue-based biomarkers for immunotherapy will likely include the simultaneous analysis of multiple cell types and their spatial interactions, as well as distinct expression patterns of immunoregulatory molecules. Here, we introduce a comprehensive platform for multispectral imaging and mapping of multiple parameters in tumor tissue sections with high-fidelity single-cell resolution. Image analysis and data handling components were drawn from the field of astronomy. Using this "AstroPath" whole-slide platform and only six markers, we identified key features in pretreatment melanoma specimens that predicted response to anti-programmed cell death-1 (PD-1)-based therapy, including CD163⁺PD-L1^- myeloid cells and CD8⁺FoxP3⁺PD-1^low/mid T cells. These features were combined to stratify long-term survival after anti-PD-1 blockade. This signature was validated in an independent cohort of patients with melanoma from a different institution.

Neoadjuvant nivolumab for patients with resectable HPV-positive and HPV-negative squamous cell carcinomas of the head and neck in the CheckMate 358 trial

BACKGROUND

Head and neck squamous cell carcinomas (HNSCCs) are common malignancies caused by carcinogens, including tobacco and alcohol, or infection with human papillomavirus (HPV). Immune checkpoint inhibitors targeting the programmed cell death 1 (PD-1) pathway are effective against unresectable recurrent/metastatic HNSCC. Here, we explored the safety and efficacy of anti-PD-1 therapy in at-risk resectable HPV-positive and HPV-negative HNSCC in the neoadjuvant setting.

METHODS

The phase I/II CheckMate 358 trial in virus-associated cancers assessed neoadjuvant nivolumab in patients with previously untreated, resectable HPV-positive or HPV-negative HNSCC. Patients received nivolumab 240 mg intravenously on days 1 and 15, with surgery planned by day 29. Safety/tolerability (primary endpoint) was assessed by monitoring adverse events (AEs) and surgical delays. Radiographic response was measured before surgery using RECIST v1.1, adapted for a single post-nivolumab evaluation. Pathologic specimens were examined for treatment response using immune-based criteria.

RESULTS

From November 2015 to December 2017, 52 patients with AJCC (seventh edition) stage III-IV resectable HNSCC received neoadjuvant nivolumab (26 HPV-positive, 26 HPV-negative). Any-grade treatment-related AEs (TRAEs) occurred in 19 patients (73.1%) and 14 patients (53.8%) in the HPV-positive and HPV-negative cohorts, respectively; grade 3-4 TRAEs occurred in five (19.2%) and three patients (11.5%), respectively. No patient had a protocol-defined TRAE-related surgical delay (>4 weeks). Thirty-eight patients were reported as undergoing complete surgical resection, 10 had a planned post-nivolumab biopsy instead of definitive surgery due to a protocol misinterpretation, and four did not undergo surgery or biopsy, including two with tumor progression. Radiographic response rates in 49 evaluable patients were 12.0% and 8.3% in the HPV-positive and HPV-negative cohorts, respectively. There were no complete pathologic responses by site or central review in operated patients. Among 17 centrally evaluable HPV-positive tumors, one (5.9%) achieved major pathological response and three (17.6%) achieved partial pathologic response (pPR); among 17 centrally evaluable HPV-negative tumors, one (5.9%) achieved pPR.

CONCLUSIONS

Neoadjuvant nivolumab was generally safe and induced pathologic regressions in HPV-positive (23.5%) and HPV-negative (5.9%) tumors. Combinatorial neoadjuvant treatment regimens, and continued postoperative therapy for high-risk tumors, are warranted in future trials to enhance the efficacy of this approach.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT02488759; https://clinicaltrials.gov/ct2/show/NCT02488759.

Three-year survival, correlates and salvage therapies in patients receiving first-line pembrolizumab for advanced Merkel cell carcinoma

Background

Merkel cell carcinoma (MCC) is an aggressive skin cancer associated with poor survival. Programmed cell death-1 (PD-1) pathway inhibitors have shown high rates of durable tumor regression compared with chemotherapy for MCC. The current study was undertaken to assess baseline and on-treatment factors associated with MCC regression and 3-year survival, and to explore the effects of salvage therapies in patients experiencing initial non-response or tumor progression after response or stable disease following first-line pembrolizumab therapy on Cancer Immunotherapy Trials Network-09/KEYNOTE-017.

Methods

In this multicenter phase II trial, 50 patients with advanced unresectable MCC received pembrolizumab 2 mg/kg every 3 weeks for ≤2 years. Patients were followed for a median of 31.8 months.

Results

Overall response rate to pembrolizumab was 58% (complete response 30%+partial response 28%; 95% CI 43.2 to 71.8). Among 29 responders, the median response duration was not reached (NR) at 3 years (range 1.0+ to 51.8+ months). Median progression-free survival (PFS) was 16.8 months (95% CI 4.6 to 43.4) and the 3-year PFS was 39.1%. Median OS was NR; the 3-year OS was 59.4% for all patients and 89.5% for responders. Baseline Eastern Cooperative Oncology Group performance status of 0, greater per cent tumor reduction, completion of 2 years of treatment and low neutrophil-to-lymphocyte ratio were associated with response and longer survival. Among patients with initial disease progression or those who developed progression after response or stable disease, some had extended survival with subsequent treatments including chemotherapies and immunotherapies.

Conclusions

This study represents the longest available follow-up from any first-line anti-programmed death-(ligand) 1 (anti-PD-(L)1) therapy in MCC, confirming durable PFS and OS in a proportion of patients. After initial tumor progression or relapse following response, some patients receiving salvage therapies survived. Improving the management of anti-PD-(L)1-refractory MCC remains a challenge and a high priority.

Trial registration number

NCT02267603.

The Genetic Evolution of Treatment-Resistant Cutaneous, Acral, and Uveal Melanomas

PURPOSE

Melanoma is a biologically heterogeneous disease composed of distinct clinicopathologic subtypes that frequently resist treatment. To explore the evolution of treatment resistance and metastasis, we used a combination of temporal and multilesional tumor sampling in conjunction with whole-exome sequencing of 110 tumors collected from 7 patients with cutaneous (n = 3), uveal (n = 2), and acral (n = 2) melanoma subtypes.

EXPERIMENTAL DESIGN

Primary tumors, metastases collected longitudinally, and autopsy tissues were interrogated. All but 1 patient died because of melanoma progression.

RESULTS

For each patient, we generated phylogenies and quantified the extent of genetic diversity among tumors, specifically among putative somatic alterations affecting therapeutic resistance.

CONCLUSIONS

In 4 patients who received immunotherapy, we found 1-3 putative acquired and intrinsic resistance mechanisms coexisting in the same patient, including mechanisms that were shared by all tumors within each patient, suggesting that future therapies directed at overcoming intrinsic resistance mechanisms may be broadly effective.

Neoadjuvant Therapy for Melanoma: A U.S. Food and Drug Administration-Melanoma Research Alliance Public Workshop

Tremendous progress has been made in treating patients with metastatic melanoma over the past decade. In that timeframe, the FDA has approved 12 novel treatments for patients with advanced unresectable melanoma, comprising both kinase-targeted therapies and immune checkpoint inhibitors (ICI), and five treatments for adjuvant (postoperative) use in patients with high-risk resectable stage III melanoma. It is not known whether outcomes can be further improved by administering kinase inhibitors or ICI in the neoadjuvant (presurgical) setting in patients with high-risk resectable melanomas. Noting research community interest in exploring the neoadjuvant approach for treating melanoma and recognizing that early harmonization of methodologies may expedite the development of therapeutics in this space, the FDA and Melanoma Research Alliance convened a public workshop on November 6, 2019, in National Harbor, Maryland, to discuss key issues. The workshop consisted of 23 faculty and included more than 250 live participants. Topics discussed included opportunities for advancing novel endpoints for regulatory purposes as well as translational research, clinical trial design considerations, and strategies for optimizing patient selection while mitigating risk.

Integrative Tumor and Immune Cell Multi-omic Analyses Predict Response to Immune Checkpoint Blockade in Melanoma

In this study, we incorporate analyses of genome-wide sequence and structural alterations with pre- and on-therapy transcriptomic and T cell repertoire features in immunotherapy-naive melanoma patients treated with immune checkpoint blockade. Although tumor mutation burden is associated with improved treatment response, the mutation frequency in expressed genes is superior in predicting outcome. Increased T cell density in baseline tumors and dynamic changes in regression or expansion of the T cell repertoire during therapy distinguish responders from non-responders. Transcriptome analyses reveal an increased abundance of B cell subsets in tumors from responders and patterns of molecular response related to expressed mutation elimination or retention that reflect clinical outcome. High-dimensional genomic, transcriptomic, and immune repertoire data were integrated into a multi-modal predictor of response. These findings identify genomic and transcriptomic characteristics of tumors and immune cells that predict response to immune checkpoint blockade and highlight the importance of pre-existing T and B cell immunity in therapeutic outcomes.

Unmet need for integrated molecular models that interpret immunotherapy response

Genomic, transcriptomic, and T and B cell sequence data integration by machine learning

T cell dynamism is a hallmark of response to immune checkpoint blockade

The combined contributions of B, T, and tumor cell features predict clinical outcome

Characterization of the tumor immune microenvironment in human papillomavirus-positive and -negative head and neck squamous cell carcinomas

Approximately 15% of advanced head and neck squamous cell carcinomas (HNSCC) respond to anti-PD-(L)1 monotherapies. Tumor PD-L1 expression and human papillomavirus (HPV) status have been proposed as biomarkers to identify patients likely to benefit from these treatments. We aimed to understand the potential immune effects of HPV in HNSCC and to characterize additional potentially targetable immune-regulatory pathways in primary, treatment-naïve tumors. CD3, CD4, CD8, CD20, CD68, FoxP3, PD-1, PD-L2, LAG-3, IDO-1, and GITR cell densities were determined in 27 HNSCC specimens. IHC for PD-L1 assessed percentage of positive tumor cells and immune cells separately or as a combined positive score (CPS), and whether PD-L1 was expressed in an adaptive or constitutive pattern (i.e., PD-L1+ tumor cells juxtaposed to TILs or in the absence of TILs, respectively). HPV testing with p16 IHC was confirmed by HPV genotyping. When compared to HPV(-) tumors (n = 14), HPV+ tumors (n = 13) contained significantly higher densities of CD3+, CD4+, CD8+, CD20+, and PD-1+ cells (P < 0.02), and there was a trend towards increased density of FoxP3 + cells. PD-L1 expression patterns did not vary by tumor viral status, suggesting possible heterogeneous mechanisms driving constitutive vs adaptive PD-L1 expression patterns in HNSCC. IDO-1 expression was abundant (> 500 IDO-1+ cells/mm² in 17/27 specimens) and was found on tumor cells as well as immune cells in 12/27 (44%) cases (range 5-80% tumor cells+). Notably, the studied markers varied on a per-patient basis and were not always related to the degree of T cell infiltration. These findings may inform therapeutic co-targeting strategies and raise consideration for a personalized treatment approach.

Conserved Interferon-γ Signaling Drives Clinical Response to Immune Checkpoint Blockade Therapy in Melanoma

We analyze the transcriptome of baseline and on-therapy tumor biopsies from 101 patients with advanced melanoma treated with nivolumab (anti-PD-1) alone or combined with ipilimumab (anti-CTLA-4). We find that T cell infiltration and interferon-γ (IFN-γ) signaling signatures correspond most highly with clinical response to therapy, with a reciprocal decrease in cell-cycle and WNT signaling pathways in responding biopsies. We model the interaction in 58 human cell lines, where IFN-γ in vitro exposure leads to a conserved transcriptome response unless cells have IFN-γ receptor alterations. This conserved IFN-γ transcriptome response in melanoma cells serves to amplify the antitumor immune response. Therefore, the magnitude of the antitumor T cell response and the corresponding downstream IFN-γ signaling are the main drivers of clinical response or resistance to immune checkpoint blockade therapy.

Abstract IA21: Translating immunotherapy from melanoma to other skin cancers

The PD-1 pathway, including the immune cell receptor Programmed Cell Death 1 (PD-1) and its ligands, PD-L1 (B7-H1) and PD-L2 (B7-DC), mediates immunosuppression within the tumor microenvironment. Drugs designed to “release the brakes” on antitumor immunity by blocking PD-1 have demonstrated substantial and durable activity in patients with advanced unresectable melanoma, as well as those with resected melanomas having a high risk for postsurgical relapse. These findings supported FDA approvals for anti-PD-1 drugs in the adjuvant and advanced melanoma settings. Research in melanoma subtypes and other kinds of cancers has identified two tumor markers associated with the likelihood of anti-PD-1 response: PD-L1 protein expression and tumor mutational burden (TMB), reflecting neoantigen load. Cutaneous melanomas are often caused by UV irradiation, harbor high TMBs, and frequently express PD-L1. Other types of skin cancers caused by UV irradiation, such as squamous cell and basal cell carcinomas, harbor high TMBs, express PD-L1, and have shown sensitivity to anti-PD-1. Merkel cell carcinoma has a unique biology, since only ~20% of cases are caused by UV light (high TMB), while the remaining 80% are associated with the oncogenic Merkel cell polyomavirus (very low TMB). Interestingly, both varieties are highly responsive to PD-1 pathway blockade, indicating that a limited number of strong tumor antigens (viral antigens) can compensate for low TMB to elicit antitumor immunity and tumor rejection. Anti-PD-1 has shown promising activity in neoadjuvant (presurgical) trials in melanoma and Merkel cell carcinoma. Neoadjuvant trials afford the opportunity for in-depth tissue analysis, and a variety of tumor markers are under investigation for correlation with treatment outcomes. The continued interrogation of tumor markers potentially predictive of clinical outcomes is expected to further refine the risk:benefit profile for PD-1/PD-L1 antagonists in melanoma and other skin cancers. Future clinical investigations will focus on difficult-to-treat populations such as immunosuppressed patients, including solid organ transplant recipients and those with HIV infection, who are at increased risk to develop aggressive skin cancers. Supported by National Institutes of Health R01 CA142779, Bristol-Myers Squibb, Melanoma Research Alliance, Barney Foundation, Laverna Hahn Charitable Trust, and Moving for Melanoma of Delaware.

Citation Format: Suzanne L. Topalian. Translating immunotherapy from melanoma to other skin cancers [abstract]. In: Proceedings of the AACR Special Conference on Melanoma: From Biology to Target; 2019 Jan 15-18; Houston, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(19 Suppl):Abstract nr IA21.

Neoadjuvant Nivolumab for Patients With Resectable Merkel Cell Carcinoma in the CheckMate 358 Trial

PURPOSE

Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer commonly driven by the Merkel cell polyomavirus (MCPyV). The programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) immunosuppressive pathway is often upregulated in MCC, and advanced metastatic MCC frequently responds to PD-1 blockade. We report what we believe to be the first trial of anti-PD-1 in the neoadjuvant setting for resectable MCC.

METHODS

In the phase I/II CheckMate 358 study of virus-associated cancer types, patients with resectable MCC received nivolumab 240 mg intravenously on days 1 and 15. Surgery was planned on day 29. Tumor regression was assessed radiographically and microscopically. Tumor MCPyV status, PD-L1 expression, and tumor mutational burden (TMB) were assessed in pretreatment tumor biopsies.

RESULTS

Thirty-nine patients with American Joint Committee on Cancer stage IIA-IV resectable MCC received ≥ 1 nivolumab dose. Three patients (7.7%) did not undergo surgery because of tumor progression (n = 1) or adverse events (n = 2). Any-grade treatment-related adverse events occurred in 18 patients (46.2%), and grade 3-4 events in 3 patients (7.7%), with no unexpected toxicities. Among 36 patients who underwent surgery, 17 (47.2%) achieved a pathologic complete response (pCR). Among 33 radiographically evaluable patients who underwent surgery, 18 (54.5%) had tumor reductions ≥ 30%. Responses were observed regardless of tumor MCPyV, PD-L1, or TMB status. At a median follow-up of 20.3 months, median recurrence-free survival (RFS) and overall survival were not reached. RFS significantly correlated with pCR and radiographic response at the time of surgery. No patient with a pCR had tumor relapse during observation.

CONCLUSION

Nivolumab administered approximately 4 weeks before surgery in MCC was generally tolerable and induced pCRs and radiographic tumor regressions in approximately one half of treated patients. These early markers of response significantly predicted improved RFS. Additional investigation of these promising findings is warranted.

Defining tumor resistance to PD-1 pathway blockade: recommendations from the first meeting of the SITC Immunotherapy Resistance Taskforce

As the field of cancer immunotherapy continues to advance at a fast pace, treatment approaches and drug development are evolving rapidly to maximize patient benefit. New agents are commonly evaluated for activity in patients who had previously received a programmed death receptor 1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitor as standard of care or in an investigational study. However, because of the kinetics and patterns of response to PD-1/PD-L1 blockade, and the lack of consistency in the clinical definitions of resistance to therapy, the design of clinical trials of new agents and interpretation of results remains an important challenge. To address this unmet need, the Society for Immunotherapy of Cancer convened a multistakeholder taskforce-consisting of experts in cancer immunotherapy from academia, industry, and government-to generate consensus clinical definitions for resistance to PD-(L)1 inhibitors in three distinct scenarios: primary resistance, secondary resistance, and progression after treatment discontinuation. The taskforce generated consensus on several key issues such as the timeframes that delineate each type of resistance, the necessity for confirmatory scans, and identified caveats for each specific resistance classification. The goal of this effort is to provide guidance for clinical trial design and to support analyses of emerging molecular and cellular data surrounding mechanisms of resistance.

Pan-Tumor Pathologic Scoring of Response to PD-(L)1 Blockade

PURPOSE

Pathologic response assessment of tumor specimens from patients receiving systemic treatment provides an early indication of therapeutic efficacy and predicts long-term survival. Grading systems for pathologic response were first developed for chemotherapy in select tumor types. Immunotherapeutic agents have a mechanism of action distinct from chemotherapy and are being used across a broad array of tumor types. A standardized, universal scoring system for pathologic response that encompasses features characteristic for immunotherapy and spans tumor types is needed.

EXPERIMENTAL DESIGN

Hematoxylin and eosin-stained slides from neoadjuvant surgical resections and on-treatment biopsies were assessed for features of immune-related pathologic response (irPR). A total of 258 specimens from patients with 11 tumor types as part of ongoing clinical trials for anti-PD-(L)1 were evaluated. An additional 98 specimens from patients receiving anti-PD-(L)1 in combination with other treatments were also reviewed, including those from three additional tumor types.

RESULTS

Common irPR features (immune activation, cell death, tissue repair, and regression bed) were present in all tumor types reviewed, including melanoma, non-small cell lung, head and neck squamous cell, Merkel cell, and renal cell carcinoma, among others. Features were consistent across primary tumors, lymph nodes, and distant metastases. Specimens from patients treated with anti-PD-(L)1 in combination with another agent also exhibited irPR features.

CONCLUSIONS

irPR features are consistent across tumor types and treatment settings. Standardized, pan-tumor irPR criteria (irPRC) are defined and associated specimen-handling considerations are described. Future, prospective studies are merited to validate irPRC in larger datasets and to associate pathologic features with long-term patient outcomes.

Neoadjuvant checkpoint blockade for cancer immunotherapy

Cancer immunotherapies that target the programmed cell death 1 (PD-1):programmed death-ligand 1 (PD-L1) immune checkpoint pathway have ushered in the modern oncology era. Drugs that block PD-1 or PD-L1 facilitate endogenous antitumor immunity and, because of their broad activity spectrum, have been regarded as a common denominator for cancer therapy. Nevertheless, many advanced tumors demonstrate de novo or acquired treatment resistance, and ongoing research efforts are focused on improving patient outcomes. Using anti-PD-1 or anti-PD-L1 treatment against earlier stages of cancer is hypothesized to be one such solution. This Review focuses on the development of neoadjuvant (presurgical) immunotherapy in the era of PD-1 pathway blockade, highlighting particular considerations for biological mechanisms, clinical trial design, and pathologic response assessments. Findings from neoadjuvant immunotherapy studies may reveal pathways, mechanisms, and molecules that can be cotargeted in new treatment combinations to increase anti-PD-1 and anti-PD-L1 efficacy.

Pathologic features of response to neoadjuvant anti-PD-1 in resected non-small-cell lung carcinoma: a proposal for quantitative immune-related pathologic response criteria (irPRC)

Background

Neoadjuvant anti-PD-1 may improve outcomes for patients with resectable NSCLC and provides a critical window for examining pathologic features associated with response. Resections showing major pathologic response to neoadjuvant therapy, defined as ≤10% residual viable tumor (RVT), may predict improved long-term patient outcome. However, %RVT calculations were developed in the context of chemotherapy (%cRVT). An immune-related %RVT (%irRVT) has yet to be developed.

Patients and methods

The first trial of neoadjuvant anti-PD-1 (nivolumab, NCT02259621) was just reported. We analyzed hematoxylin and eosin-stained slides from the post-treatment resection specimens of the 20 patients with non-small-cell lung carcinoma who underwent definitive surgery. Pretreatment tumor biopsies and preresection radiographic 'tumor' measurements were also assessed.

Results

We found that the regression bed (the area of immune-mediated tumor clearance) accounts for the previously noted discrepancy between CT imaging and pathologic assessment of residual tumor. The regression bed is characterized by (i) immune activation-dense tumor infiltrating lymphocytes with macrophages and tertiary lymphoid structures; (ii) massive tumor cell death-cholesterol clefts; and (iii) tissue repair-neovascularization and proliferative fibrosis (each feature enriched in major pathologic responders versus nonresponders, P < 0.05). This distinct constellation of histologic findings was not identified in any pretreatment specimens. Histopathologic features of the regression bed were used to develop 'Immune-Related Pathologic Response Criteria' (irPRC), and these criteria were shown to be reproducible amongst pathologists. Specifically, %irRVT had improved interobserver consistency compared with %cRVT [median per-case %RVT variability 5% (0%-29%) versus 10% (0%-58%), P = 0.007] and a twofold decrease in median standard deviation across pathologists within a sample (4.6 versus 2.2, P = 0.002).

Conclusions

irPRC may be used to standardize pathologic assessment of immunotherapeutic efficacy. Long-term follow-up is needed to determine irPRC reliability as a surrogate for recurrence-free and overall survival.

Mechanisms regulating PD-L1 expression on tumor and immune cells

BACKGROUND

The PD-1/PD-L1 checkpoint is a central mediator of immunosuppression in the tumor immune microenvironment (TME) and is primarily associated with IFN-g signaling. To characterize other factors regulating PD-L1 expression on tumor and/or immune cells, we investigated TME-resident cytokines and the role of transcription factors in constitutive and cytokine-induced PD-L1 expression.

METHODS

Thirty-four cultured human tumor lines [18 melanomas (MEL), 12 renal cell carcinomas (RCC), 3 squamous cell carcinomas of the head and neck (SCCHN), and 1 non-small-cell lung carcinoma (NSCLC)] and peripheral blood monocytes (Monos) were treated with cytokines that we detected in the PD-L1+ TME by gene expression profiling, including IFN-g, IL-1a, IL-10, IL-27 and IL-32g. PD-L1 cell surface protein expression was detected by flow cytometry, and mRNA by quantitative real-time PCR. Total and phosphorylated STAT1, STAT3, and p65 proteins were detected by Western blotting, and the genes encoding these proteins were knocked down with siRNAs. Additionally, the proximal promoter region of PDL1 (CD274) was sequenced in 33 cultured tumors.

RESULTS

PD-L1 was constitutively expressed on 1/17 cultured MELs, 8/11 RCCs, 3/3 SCCHNs, and on Monos. Brief IFN-g exposure rapidly induced PD-L1 on all tumor cell lines and Monos regardless of constitutive PD-L1 expression. PD-L1 mRNA levels were associated with protein expression, which was diminished by exposure to transcriptional inhibitors. siRNA knockdown of STAT1 but not STAT3 reduced IFN-g- and IL-27-induced PD-L1 protein expression on tumor cells. In contrast, STAT3 knockdown in Monos reduced IL-10-induced PD-L1 protein expression, and p65 knockdown in tumor cells reduced IL-1a-induced PD-L1 expression. Notably, constitutive PD-L1 expression was not affected by knocking down STAT1, STAT3, or p65. Differential effects of IFN-g, IL-1a, and IL-27 on individual tumor cell lines were not due to PDL1 promoter polymorphisms.

CONCLUSIONS

Multiple cytokines found in an immune-reactive TME may induce PD-L1 expression on tumor and/or immune cells through distinct signaling mechanisms. Factors driving constitutive PD-L1 expression were not identified in this study. Understanding complex mechanisms underlying PD-L1 display in the TME may allow treatment approaches mitigating expression of this immunosuppressive ligand, to enhance the impact of PD-1 blockade.

Safety and Efficacy of Nivolumab Monotherapy in Recurrent or Metastatic Cervical, Vaginal, or Vulvar Carcinoma: Results From the Phase I/II CheckMate 358 Trial

PURPOSE

Nivolumab was assessed in patients with virus-associated tumors in the phase I/II CheckMate 358 trial (ClinicalTrials.gov identifier: NCT02488759). We report on patients with recurrent/metastatic cervical, vaginal, or vulvar cancers.

PATIENTS AND METHODS

Patients received nivolumab 240 mg every 2 weeks. Although patients with unknown human papillomavirus status were enrolled, patients known to have human papillomavirus-negative tumors were ineligible. The primary end point was objective response rate. Duration of response (DOR), progression-free survival, and overall survival were secondary end points. Safety and patient-reported outcomes were exploratory end points.

RESULTS

Twenty-four patients (cervical, n = 19; vaginal/vulvar, n = 5) were enrolled. Most patients had received prior systemic therapy for metastatic disease (cervical, 78.9%; vaginal/vulvar, 80.0%). Objective response rates were 26.3% (95% CI, 9.1 to 51.2) for cervical cancer and 20.0% (95% CI, 0.5 to 71.6) for vaginal/vulvar cancers. At a median follow-up of 19.2 months, median DOR was not reached (range, 23.3 to 29.5+ months; + indicates a censored observation) in the five responding patients in the cervical cohort; the DOR was 5.0 months in the single responding patient in the vaginal/vulvar cohort. Median overall survival was 21.9 months (95% CI, 15.1 months to not reached) among patients with cervical cancer. Any-grade treatment-related adverse events were reported in 12 of 19 patients (63.2%) in the cervical cohort and all five patients in the vaginal/vulvar cohort; there were no treatment-related deaths. In the cervical cohort, nivolumab treatment generally resulted in stabilization of patient-reported outcomes associated with health status and health-related quality of life.

CONCLUSION

The efficacy of nivolumab in patients with recurrent/metastatic cervical and vaginal or vulvar cancers is promising and warrants additional investigation. No new safety signals were identified with nivolumab treatment in this population.

Five-Year Survival and Correlates Among Patients With Advanced Melanoma, Renal Cell Carcinoma, or Non-Small Cell Lung Cancer Treated With Nivolumab

IMPORTANCE

Nivolumab, a monoclonal antibody that inhibits programmed cell death 1, is approved by the US Food and Drug Administration for treating advanced melanoma, renal cell carcinoma (RCC), non-small cell lung cancer (NSCLC), and other malignancies. Data on long-term survival among patients receiving nivolumab are limited.

OBJECTIVES

To analyze long-term overall survival (OS) among patients receiving nivolumab and identify clinical and laboratory measures associated with tumor regression and OS.

DESIGN, SETTING, AND PARTICIPANTS

This was a secondary analysis of the phase 1 CA209-003 trial (with expansion cohorts), which was conducted at 13 US medical centers and included 270 patients with advanced melanoma, RCC, or NSCLC who received nivolumab and were enrolled between October 30, 2008, and December 28, 2011. The analyses were either specified in the original protocol or included in subsequent protocol amendments that were implemented between 2008 and 2012. Statistical analysis was performed from October 30, 2008, to November 11, 2016.

INTERVENTION

In the CA209-003 trial, patients received nivolumab (0.1-10.0 mg/kg) every 2 weeks in 8-week cycles for up to 96 weeks, unless they developed progressive disease, achieved a complete response, experienced unacceptable toxic effects, or withdrew consent.

MAIN OUTCOMES AND MEASURES

Safety and activity of nivolumab; OS was a post hoc end point with a minimum follow-up of 58.3 months.

RESULTS

Of 270 patients included in this analysis, 107 (39.6%) had melanoma (72 [67.3%] male; median age, 61 [range, 29-85] years), 34 (12.6%) had RCC (26 [76.5%] male; median age, 58 [range, 35-74] years), and 129 (47.8%) had NSCLC (79 [61.2%] male; median age, 65 [range, 38-85] years). Overall survival curves showed estimated 5-year rates of 34.2% among patients with melanoma, 27.7% among patients with RCC, and 15.6% among patients with NSCLC. In a multivariable analysis, the presence of liver (odds ratio [OR], 0.31; 95% CI, 0.12-0.83; P = .02) or bone metastases (OR, 0.31; 95% CI, 0.10-0.93; P = .04) was independently associated with reduced likelihood of survival at 5 years, whereas an Eastern Cooperative Oncology Group performance status of 0 (OR, 2.74; 95% CI, 1.43-5.27; P = .003) was independently associated with an increased likelihood of 5-year survival. Overall survival was significantly longer among patients with treatment-related AEs of any grade (median, 19.8 months; 95% CI, 13.8-26.9 months) or grade 3 or more (median, 20.3 months; 95% CI, 12.5-44.9 months) compared with those without treatment-related AEs (median, 5.8 months; 95% CI, 4.6-7.8 months) (P < .001 for both comparisons based on hazard ratios).

CONCLUSIONS AND RELEVANCE

Nivolumab treatment was associated with long-term survival in a subset of heavily pretreated patients with advanced melanoma, RCC, or NSCLC. Characterizing factors associated with long-term survival may inform treatment approaches and strategies for future clinical trial development.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00730639.

Durable Tumor Regression and Overall Survival in Patients With Advanced Merkel Cell Carcinoma Receiving Pembrolizumab as First-Line Therapy

PURPOSE

Merkel cell carcinoma (MCC) is an aggressive skin cancer often caused by the Merkel cell polyomavirus. Clinical trials of programmed cell death-1 pathway inhibitors for advanced MCC (aMCC) demonstrate increased progression-free survival (PFS) compared with historical chemotherapy data. However, response durability and overall survival (OS) data are limited.

PATIENTS AND METHODS

In this multicenter phase II trial (Cancer Immunotherapy Trials Network-09/Keynote-017), 50 adults naïve to systemic therapy for aMCC received pembrolizumab (2 mg/kg every 3 weeks) for up to 2 years. Radiographic responses were assessed centrally per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1.

RESULTS

Among 50 patients, the median age was 70.5 years, and 64% had Merkel cell polyomavirus-positive tumors. The objective response rate (ORR) to pembrolizumab was 56% (complete response [24%] plus partial response [32%]; 95% CI, 41.3% to 70.0%), with ORRs of 59% in virus-positive and 53% in virus-negative tumors. Median follow-up time was 14.9 months (range, 0.4 to 36.4+ months). Among 28 responders, median response duration was not reached (range, 5.9 to 34.5+ months). The 24-month PFS rate was 48.3%, and median PFS time was 16.8 months (95% CI, 4.6 months to not estimable). The 24-month OS rate was 68.7%, and median OS time was not reached. Although tumor viral status did not correlate with ORR, PFS, or OS, there was a trend toward improved PFS and OS in patients with programmed death ligand-1-positive tumors. Grade 3 or greater treatment-related adverse events occurred in 14 (28%) of 50 patients and led to treatment discontinuation in seven (14%) of 50 patients, including one treatment-related death.

CONCLUSION

Here, we present the longest observation to date of patients with aMCC receiving first-line anti-programmed cell death-1 therapy. Pembrolizumab demonstrated durable tumor control, a generally manageable safety profile, and favorable OS compared with historical data from patients treated with first-line chemotherapy.

Merkel cell polyomavirus-specific immune responses in patients with Merkel cell carcinoma receiving anti-PD-1 therapy

BACKGROUND

Merkel cell carcinoma (MCC) is an aggressive skin cancer that frequently responds to anti-PD-1 therapy. MCC is associated with sun exposure and, in 80% of cases, Merkel cell polyomavirus (MCPyV). MCPyV-specific T and B cell responses provide a unique opportunity to study cancer-specific immunity throughout PD-1 blockade therapy.

METHODS

Immune responses were assessed in patients (n = 26) with advanced MCC receiving pembrolizumab. Peripheral blood mononuclear cells (PBMC) were collected at baseline and throughout treatment. MCPyV-oncoprotein antibodies were quantified and T cells were assessed for MCPyV-specificity via tetramer staining and/or cytokine secretion. Pre-treatment tumor biopsies were analyzed for T cell receptor clonality.

RESULTS

MCPyV oncoprotein antibodies were detectable in 15 of 17 (88%) of virus-positive MCC (VP-MCC) patients. Antibodies decreased in 10 of 11 (91%) patients with responding tumors. Virus-specific T cells decreased over time in patients who had a complete response, and increased in patients who had persistent disease. Tumors that were MCPyV(+) had a strikingly more clonal (less diverse) intratumoral TCR repertoire than virus-negative tumors (p = 0.0001).

CONCLUSIONS

Cancer-specific T and B cell responses generally track with disease burden during PD-1 blockade, in proportion to presence of antigen. Intratumoral TCR clonality was significantly greater in VP-MCC than VN-MCC tumors, suggesting expansion of a limited number of dominant clones in response to fewer immunogenic MCPyV antigens. In contrast, VN-MCC tumors had lower clonality, suggesting a diverse T cell response to numerous neoantigens. These findings reveal differences in tumor-specific immunity for VP-MCC and VN-MCC, both of which often respond to anti-PD-1 therapy.

Multidimensional, quantitative assessment of PD-1/PD-L1 expression in patients with Merkel cell carcinoma and association with response to pembrolizumab

Background

We recently reported a 56% objective response rate in patients with advanced Merkel cell carcinoma (MCC) receiving pembrolizumab. However, a biomarker predicting clinical response was not identified.

Methods

Pretreatment FFPE tumor specimens (n = 26) were stained for CD8, PD-L1, and PD-1 by immunohistochemistry/immunofluorescence (IHC/IF), and the density and distribution of positive cells was quantified to determine the associations with anti-PD-1 response. Multiplex IF was used to test a separate cohort of MCC archival specimens (n = 16), to identify cell types expressing PD-1.

Results

Tumors from patients who responded to anti-PD-1 showed higher densities of PD-1+ and PD-L1+ cells when compared to non-responders (median cells/mm², 70.7 vs. 6.7, p = 0.03; and 855.4 vs. 245.0, p = 0.02, respectively). There was no significant association of CD8+ cell density with clinical response. Quantification of PD-1+ cells located within 20 μm of a PD-L1+ cell showed that PD-1/PD-L1 proximity was associated with clinical response (p = 0.03), but CD8/PD-L1 proximity was not. CD4+ and CD8+ cells in the TME expressed similar amounts of PD-1.

Conclusions

While the binomial presence or absence of PD-L1 expression in the TME was not sufficient to predict response to anti-PD-1 in patients with MCC, we show that quantitative assessments of PD-1+ and PD-L1+ cell densities as well as the geographic interactions between these two cell populations correlate with clinical response. Cell types expressing PD-1 in the TME include CD8+ T-cells, CD4+ T-cells, T_regs, and CD20+ B-cells, supporting the notion that multiple cell types may potentiate tumor regression following PD-1 blockade.

Electronic supplementary material

The online version of this article (10.1186/s40425-018-0404-0) contains supplementary material, which is available to authorized users.

Abstract LB-154: Pathologic features of response to neoadjuvant anti-PD-1 in resected non-small cell lung carcinoma (NSCLC): A proposal for quantitative immune-related pathologic response criteria (irPRC)

There is great interest in using PD-(L)1 blockading drugs as neoadjuvant therapy for patients with resectable NSCLC. Early results demonstrated a 45% (9/20) major pathologic response (MPR) rate in patients with Stage I-III NSCLC after receiving nivolumab (NCT02259621). Major pathologic response (MPR) criteria were developed in the context of cytotoxic chemotherapy, defined as ≤10% residual viable tumor cells (RVT). The features of immune-mediated tumor regression following anti-PD-1 have yet to be described. We reviewed H&E-stained slides from resection specimens in 19 patients treated with neoadjuvant nivolumab [n=9 MPR, n=3 partial responders, n=7 non-responders (&gt;70% RVT)] to identify histopathologic features of immune-mediated tumor regression. Specimens were assessed for immune characteristics (tumor infiltrating lymphocyte (TIL) and macrophage density, and presence/absence of, lymphoid aggregates, tertiary lymphoid structures (TLS), dense plasma cell infiltrates, neutrophils, giant cells, etc.) and non-immune features (necrosis, hemosiderin, hyalinized and proliferative fibrosis). We found that immune-mediated tumor regression is characterized by a fibroinflammatory stroma with features of (1) immune activation, including dense TIL and macrophages, TLS, and granulomas; (2) massive [tumor] cell death, including cholesterol clefts and giant cells; and (3) tissue repair, including neovascularization and proliferative fibrosis (each enriched in MPR vs. non-responders, Fisher's exact test p&lt;0.05). An “outside-in” pattern of regression was noted, which has important implications for defining total tumor bed area. As such, we propose “Immune-Related Pathologic Response Criteria” (irPRC), with tumor bed defined by RVT + necrosis + surrounding fibroinflammatory stroma. The areas of each are summed across all slides to calculate %RVT (RVT area/tumor bed area). This differs from chemotherapy MPR criteria, where %RVT is determined for each slide and then averaged, and the distinct fibroinflammatory regression stroma and peripheral regression bed are not acknowledged. The surgical resection specimens were then evaluated by four independent pathologists blinded to response to assess inter-observer variability. Compared to %RVT using chemotherapy criteria, irPRC had improved inter-observer variability [median per-case %RVT variability 5% (0-29%) vs. 10% (0-58%), paired t test p=0.007] and a two-fold decrease in median standard deviation across pathologists within a sample (4.6 vs 2.2, F-test p=0.002). We propose irPRC to standardize pathologic assessment of immune-mediated tumor regression and immunotherapeutic efficacy. Long-term follow up is needed to determine the reliability of irPRC as a surrogate for clinical outcomes such as recurrence-free and overall survival.

Citation Format: Tricia R. Cottrell, Julie E. Stein, Jamie E. Chaft, Elizabeth D. Thompson, Natasha Rekhtman, Valsamo Anagnostou, Kellie N. Smith, Amy S. Duffield, Robert A. Anders, James M. Isbell, David R. Jones, Jonathan D. Cuda, Richard Battafarano, Stephen C. Yang, Peter B. Illei, Edward Gabrielson, Frederic Askin, Moises Velez, Matthew D. Hellmann, Jennifer L. Sauter, Ludmila Danilova, Victor E. Velculescu, Jedd D. Wolchok, Suzanne L. Topalian, Julie R. Brahmer, Drew M. Pardoll, Ashley Cimino-Mathews, Patrick M. Forde, Janis M. Taube. Pathologic features of response to neoadjuvant anti-PD-1 in resected non-small cell lung carcinoma (NSCLC): A proposal for quantitative immune-related pathologic response criteria (irPRC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-154.

Abstract 4750: The immunosuppressive tumor microenvironment (TME) in nasopharyngeal carcinoma: implications for immunotherapy

Nasopharyngeal carcinoma (NPC) is an EBV-driven tumor that shows variable expression of PD-L1 and ~20% objective response rate to anti-PD-1 monotherapy. As novel immune checkpoint inhibitors are being developed, combination therapies may allow for more effective treatment of both newly diagnosed and relapsed NPC. We characterized the TME in 13 cases of EBV+ NPC from the Johns Hopkins Pathology archives (7 primary tumors, 6 metastases). EBV status was confirmed with EBER ISH. Immunohistochemistry (IHC) was conducted on all cases for CD3, CD4, CD8, CD20, FoxP3, PD-1, PD-L1, LAG-3, TIM-3, GITR, IDO, COX2, and pSTAT3. Gene expression profiling (GEP) was performed on 7 cases with sufficient material (4 primary lesions, 3 metastases), using multiplex qRT-PCR for a panel of 61 candidate immune-related genes (Duffield, Blood Advances 2017). The immunosuppressive ligand PD-L1 was expressed on tumor cells in 11/13 cases (mean 22% tumor cells+, range 0-57%), as well as on infiltrating macrophages. The NPC inflammatory infiltrate was diverse, including CD4+, CD8+, CD20+ and CD68+ cells, and showed variable expression of immune-regulatory molecules. In all 13 cases, lymphocytes expressing PD-1 (mean 36% positive, range 8-70%), LAG-3 (7%; 1-30%) and GITR (12%; 2-27%) were found. FoxP3+ and TIM-3+ lymphocytes were infrequent. IDO+ macrophages were also infrequent; however, 7/13 NPCs showed expression of the immunosuppressive metabolic enzyme IDO by a proportion of tumor cells. Compared to 12 EBV+ Hodgkin lymphomas (Duffield, Blood Advances 2017), EBV+ NPCs demonstrated a Th17 cytokine profile with overexpression of IL1A, IL17RC, IL23A, and IL23R. The generation of pathogenic Th17 responses requires phosphorylation of the STAT3 transcription factor, and IHC confirmed that a subset of inflammatory cells in all NPC cases expressed pSTAT3 (mean 10%; range 1-40%). Additionally, upregulated gene expression characterizing activated macrophages was found (IDO, IL1A, IL12A, LYZ, TLR3). Of note, several molecules upregulated in the NPC TME are capable of inducing PD-L1 expression on human monocytes in vitro, including IL-1A and IL-32-gamma (Taube, Clin Cancer Res 2015; Duffield, Blood Advances 2017). Importantly PTGS2 (COX2), with known proinflammatory and immunosuppressive properties, was over-expressed in NPCs along with the downstream modulator CXCL8 (IL-8); IHC revealed COX2 expression in tumor cells but not infiltrating immune cells. In summary, NPC is characterized by markers of an immunosuppressive TME, including immune checkpoints and metabolic modulators. While these findings should be explored in a larger cohort, they have potential implications for designing combination NPC treatment regimens with anti-PD-1, which might include inhibitors of LAG-3, IDO, IL-17/-23, COX2, and/or IL-8. Funded by the Bristol-Myers Squibb International Immuno-Oncology Network and NCI R01 CA142779

Citation Format: Amy S. Duffield, Maria Libera Ascierto, Robert A. Anders, Janis M. Taube, Tracee L. McMiller, Elizabeth L. Engle, Alan K. Meeker, Alan E. Berger, Drew M. Pardoll, Richard F. Ambinder, Suzanne L. Topalian. The immunosuppressive tumor microenvironment (TME) in nasopharyngeal carcinoma: implications for immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4750.

Neoadjuvant PD-1 Blockade in Resectable Lung Cancer

BACKGROUND

Antibodies that block programmed death 1 (PD-1) protein improve survival in patients with advanced non-small-cell lung cancer (NSCLC) but have not been tested in resectable NSCLC, a condition in which little progress has been made during the past decade.

METHODS

In this pilot study, we administered two preoperative doses of PD-1 inhibitor nivolumab in adults with untreated, surgically resectable early (stage I, II, or IIIA) NSCLC. Nivolumab (at a dose of 3 mg per kilogram of body weight) was administered intravenously every 2 weeks, with surgery planned approximately 4 weeks after the first dose. The primary end points of the study were safety and feasibility. We also evaluated the tumor pathological response, expression of programmed death ligand 1 (PD-L1), mutational burden, and mutation-associated, neoantigen-specific T-cell responses.

RESULTS

Neoadjuvant nivolumab had an acceptable side-effect profile and was not associated with delays in surgery. Of the 21 tumors that were removed, 20 were completely resected. A major pathological response occurred in 9 of 20 resected tumors (45%). Responses occurred in both PD-L1-positive and PD-L1-negative tumors. There was a significant correlation between the pathological response and the pretreatment tumor mutational burden. The number of T-cell clones that were found in both the tumor and peripheral blood increased systemically after PD-1 blockade in eight of nine patients who were evaluated. Mutation-associated, neoantigen-specific T-cell clones from a primary tumor with a complete response on pathological assessment rapidly expanded in peripheral blood at 2 to 4 weeks after treatment; some of these clones were not detected before the administration of nivolumab.

CONCLUSIONS

Neoadjuvant nivolumab was associated with few side effects, did not delay surgery, and induced a major pathological response in 45% of resected tumors. The tumor mutational burden was predictive of the pathological response to PD-1 blockade. Treatment induced expansion of mutation-associated, neoantigen-specific T-cell clones in peripheral blood. (Funded by Cancer Research Institute-Stand Up 2 Cancer and others; ClinicalTrials.gov number, NCT02259621 .).

Association of HIV Status With Local Immune Response to Anal Squamous Cell Carcinoma: Implications for Immunotherapy

IMPORTANCE

The programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) pathway play an important immunosuppressive role in cancer and chronic viral infection, and have been effectively targeted in cancer therapy. Anal squamous cell carcinoma (SCC) is associated with both human papillomavirus and HIV infection. To date, patients with HIV have been excluded from most trials of immune checkpoint blocking agents, such as anti-PD-1 and anti-PD-L1, because it was assumed that their antitumor immunity was compromised compared with immunocompetent patients.

OBJECTIVE

To compare the local tumor immune microenvironment (TME) in anal SCCs from HIV-positive and HIV-negative patients.

DESIGN, SETTING, AND PARTICIPANTS

Anal SCC tumor specimens derived from the AIDS and Cancer Specimen Resource (National Cancer Institute) and Johns Hopkins Hospital included specimens. Tumors were subjected to immunohistochemical analysis for immune checkpoints (PD-L1, PD-1, LAG-3) and immune cell (IC) subsets (CD3, CD4, CD8, CD68). Expression profiling for immune-related genes was performed on select HIV-positive and HIV-negative cases in PD-L1+ tumor areas associated with ICs.

MAIN OUTCOMES AND MEASURES

Programmed death-ligand 1 expression on tumor cells and ICs, PD-L1 patterns (adaptive vs constitutive), degree of IC infiltration, quantified densities of IC subsets, and gene expression profiles in anal SCCs from HIV-positive vs HIV-negative patients.

RESULTS

Approximately half of 40 tumor specimens from 23 HIV-positive and 17 HIV-negative patients (29 men and 11 women; mean [SD] age, 51 [9.9] years) demonstrated tumor cell PD-L1 expression, regardless of HIV status. Median IC densities were not significantly decreased in HIV-associated tumors for any cellular subset studied. Both adaptive (IC-associated) and constitutive PD-L1 expression patterns were observed. Immune cell PD-L1 expression correlated with increasing intensity of IC infiltration (r = 0.52; 95% CI, 0.26-0.78; P < .001) and with CD8+ T-cell density (r = 0.35; 95% CI, 0.11-0.59; P = .03). Gene expression profiling revealed comparable levels of IFNG in the TME of both HIV-positive and HIV-negative patients. A significant increase in IL18 expression levels was observed in HIV-associated anal SCCs (fold change, 12.69; P < .001).

CONCLUSIONS AND RELEVANCE

HIV status does not correlate with the degree or composition of IC infiltration or PD-L1 expression in anal SCC. These findings demonstrate an immune-reactive TME in anal SCCs from HIV-positive patients and support clinical investigations of PD-1/PD-L1 checkpoint blockade in anal SCC, irrespective of patient HIV status.

Abstract 662: The differential association of PD-1, PD-L1, and CD8+ cells with response to pembrolizumab and presence of Merkel cell polyomavirus (MCPyV) in patients with Merkel cell carcinoma (MCC)

We recently reported a 56% objective response rate in patients with advanced MCC receiving pembrolizumab (anti-PD-1) as first-line therapy. However, a tumor biomarker predicting clinical response was not defined. The purpose of this study was to determine potential associations of anti-PD-1 response (RECIST 1.1, analysis 8/1/16) and the presence of MCPyV, with the density and distribution of CD8+, PD-1+ and PD-L1+ cell populations in the tumor microenvironment (TME). Pretreatment FFPE tumor specimens were stained for CD8 (n=23) and PD-L1 (n=16, 22C3 assay) with immunohistochemistry (IHC). Immunofluorescence (IF) was used to detect PD-1 (n=16). Intratumoral (IT), peritumoral (PT, 100 um zone) and total (PT+IT) densities of PD-1+ and CD8+ immune cells (IC) were determined with digital image analysis. PD-L1+ cases had &gt;1% tumor cells (TC) expressing PD-L1. Tumors from patients who responded to anti-PD-1 showed higher densities of PD-1+ cells in the IT, PT, and IT+PT regions when compared to non-responders (Mann-Whitney test, p-value=0.03, 0.06, 0.03, respectively). There was no significant association of response with CD8+ IC densities (IT, PT or total) or TC PD-L1 expression. Similarly, when we quantified the number of PD-1+ IC located within 15 um from a PD-L1+ cell (TC or IC), an association was observed between PD-1 and PD-L1 proximity and clinical response (Mann-Whitney test, p-value =0.04), but not CD8 and PD-L1 proximity. Because viral neoantigens can elicit a strong immune response, we also studied these TME factors for their potential associations with MCPyV. We found the presence of virus was significantly associated with increased densities of PT CD8+ cells (Mann-Whitney test, p-value=0.008) and TC PD-L1 expression (Fisher's test, p-value=0.04), but not PD-1+ IC. A more extensive multiplex IF panel (CD8, PD-1, PD-L1, CD68, FoxP3, NSE) analysis was performed on select pre-treatment specimens using the Vectra multispectral imaging system (Perkin Elmer) to explore this divergence. We found that only ~60% of observed total PD-1 expression was displayed by CD8+ cells. Although preliminary, our results suggest a relationship between PD-1+ cells and response to anti-PD-1 therapy and highlight that lymphocyte subsets other than CD8+ T-cells may contribute to the observed response. Further studies in larger cohorts are needed to validate these results.

Citation Format: Nicolas A. Giraldo, Genevieve J. Kaunitz, Tricia R. Cottrell, Sneha Berry, Joel C. Sunshine, Peter Nguyen, Haiying Xu, Aleksandra Orgutsova, Candice D. Church, Natalie J. Miller, Jennifer H. Yearley, Evan J. Lipson, Ludmila Danilova, Paul T. Nghiem, Suzanne L. Topalian, Janis M. Taube. The differential association of PD-1, PD-L1, and CD8+ cells with response to pembrolizumab and presence of Merkel cell polyomavirus (MCPyV) in patients with Merkel cell carcinoma (MCC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 662. doi:10.1158/1538-7445.AM2017-662

Transcriptional Mechanisms of Resistance to Anti-PD-1 Therapy

Purpose: To explore factors associated with response and resistance to anti-PD-1 therapy, we analyzed multiple disease sites at autopsy in a patient with widely metastatic melanoma who had a heterogeneous response.Materials and Methods: Twenty-six melanoma specimens (four premortem, 22 postmortem) were subjected to whole exome sequencing. Candidate immunologic markers and gene expression were assessed in 10 cutaneous metastases showing response or progression during therapy.Results: The melanoma was driven by biallelic inactivation of NF1 All lesions had highly concordant mutational profiles and copy number alterations, indicating linear clonal evolution. Expression of candidate immunologic markers was similar in responding and progressing lesions. However, progressing cutaneous metastases were associated with overexpression of genes associated with extracellular matrix and neutrophil function.Conclusions: Although mutational and immunologic differences have been proposed as the primary determinants of heterogeneous response/resistance to targeted therapies and immunotherapies, respectively, differential lesional gene expression profiles may also dictate anti-PD-1 outcomes. Clin Cancer Res; 23(12); 3168-80. ©2017 AACRSee related commentary by Wilmott et al., p. 2921.

Prediction of Response to Immune Checkpoint Inhibitor Therapy Using Early-Time-Point 18F-FDG PET/CT Imaging in Patients with Advanced Melanoma

The purpose of this study was to evaluate ¹⁸F-FDG PET/CT scanning as an early predictor of response to immune checkpoint inhibitors (ICIs) in patients with advanced melanoma. Methods: Twenty patients with advanced melanoma receiving ICI prospectively underwent ¹⁸F-FDG PET/CT at 3 scan intervals: before treatment initiation (SCAN-1), at days 21-28 (SCAN-2), and at 4 mo (SCAN-3). This study was approved by the institutional review board, and informed consent was received from all patients who were enrolled between April 2012 and December 2013. Tumor response at each posttreatment time point was assessed according to RECIST 1.1, immune-related response criteria, PERCIST (PERCIST 1.0), and European Organization for Research and Treatment of Cancer (EORTC) criteria. Performance characteristics of each metric to predict best overall response (BOR) at ≥ 4 mo were assessed. Results: Twenty evaluable patients were treated with ipilimumab (n = 16), BMS-936559 (n = 3), or nivolumab (n = 1). BOR at ≥ 4 mo included complete response (n = 2), partial response (n = 2), stable disease (n = 1), and progressive disease (n = 15). Response evaluations at SCAN-2 using RECIST 1.1, immune-related response criteria, PERCIST, and EORTC criteria demonstrated accuracies of 75%, 70%, 70%, and 65%, respectively, to predict BOR at ≥ 4 mo. Interestingly, the optimal PERCIST and EORTC threshold values at SCAN-2 to predict BOR were >15.5% and >14.7%, respectively. By combining anatomic and functional imaging data collected at SCAN-2, we developed criteria to predict eventual response to ICI with 100% sensitivity, 93% specificity, and 95% accuracy. Conclusion: Combining functional and anatomic imaging parameters from ¹⁸F-FDG PET/CT scans performed early in ICI appears predictive for eventual response in patients with advanced melanoma. These findings require validation in larger cohorts.

Safety Profile of Nivolumab Monotherapy: A Pooled Analysis of Patients With Advanced Melanoma

Purpose We conducted a retrospective analysis to assess the safety profile of nivolumab monotherapy in patients with advanced melanoma and describe the management of adverse events (AEs) using established safety guidelines. Patients and Methods Safety data were pooled from four studies, including two phase III trials, with patients who received nivolumab 3 mg/kg once every 2 weeks. We evaluated rate of treatment-related AEs, time to onset and resolution of select AEs (those with potential immunologic etiology), and impact of select AEs and suppressive immune-modulating agents (IMs) on antitumor efficacy. Results Among 576 patients, 71% (95% CI, 67% to 75%) experienced any-grade treatment-related AEs (most commonly fatigue [25%], pruritus [17%], diarrhea [13%], and rash [13%]), and 10% (95% CI, 8% to 13%) experienced grade 3 to 4 treatment-related AEs. No drug-related deaths were reported. Select AEs (occurring in 49% of patients) were most frequently skin related, GI, endocrine, and hepatic; grade 3 to 4 select AEs occurred in 4% of patients. Median time to onset of select AEs ranged from 5 weeks for skin to 15 weeks for renal AEs. Approximately 24% of patients received systemic IMs to manage select AEs, which in most cases resolved. Adjusting for number of doses, objective response rate (ORR) was significantly higher in patients who experienced treatment-related select AEs of any grade compared with those who did not. ORRs were similar in patients who did and patients who did not receive systemic IMs. Conclusion Treatment-related AEs with nivolumab monotherapy were primarily low grade, and most resolved with established safety guidelines. Use of IMs did not affect ORR, although treatment-related select AEs of any grade were associated with higher ORR, but no progression-free survival benefit.

Identification and Characterization of Complex Glycosylated Peptides Presented by the MHC Class II Processing Pathway in Melanoma

The MHC class II (MHCII) processing pathway presents peptides derived from exogenous or membrane-bound proteins to CD4+ T cells. Several studies have shown that glycopeptides are necessary to modulate CD4+ T cell recognition, though glycopeptide structures in these cases are generally unknown. Here, we present a total of 93 glycopeptides from three melanoma cell lines and one matched EBV-transformed line with most found only in the melanoma cell lines. The glycosylation we detected was diverse and comprised 17 different glycoforms. We then used molecular modeling to demonstrate that complex glycopeptides are capable of binding the MHC and may interact with complementarity determining regions. Finally, we present the first evidence of disulfide-bonded peptides presented by MHCII. This is the first large scale study to sequence glyco- and disulfide bonded MHCII peptides from the surface of cancer cells and could represent a novel avenue of tumor activation and/or immunoevasion.

The Intratumoral Balance between Metabolic and Immunologic Gene Expression Is Associated with Anti-PD-1 Response in Patients with Renal Cell Carcinoma

Pretreatment tumor PD-L1 expression has been shown to correlate with response to anti-PD-1/PD-L1 therapies. Yet, most patients with PD-L1(+) tumors do not respond to treatment. The current study was undertaken to investigate mechanisms underlying the failure of PD-1-targeted therapies in patients with advanced renal cell carcinoma (RCC) whose tumors express PD-L1. Formalin-fixed, paraffin-embedded pretreatment tumor biopsies expressing PD-L1 were derived from 13 RCC patients. RNA was isolated from PD-L1(+) regions and subjected to whole genome microarray and multiplex quantitative (q)RT-PCR gene expression analysis. A balance between gene expression profiles reflecting metabolic pathways and immune functions was associated with clinical outcomes following anti-PD-1 therapy. In particular, the expression of genes involved in metabolic and solute transport functions such as UGT1A family members, also found in kidney cancer cell lines, was associated with treatment failure in patients with PD-L1(+) RCC. Conversely, tumors from responding patients overexpressed immune markers such as BACH2, a regulator of CD4(+) T-cell differentiation, and CCL3 involved in leukocyte migration. These findings suggest that tumor cell-intrinsic metabolic factors may contribute to treatment resistance in RCC, thus serving as predictive markers for treatment outcomes and potential new targets for combination therapy regimens with anti-PD-1. Cancer Immunol Res; 4(9); 726-33. ©2016 AACRSee related Spotlight by Ohashi, p. 719.

Melanoma and immunotherapy bridge 2015 : Naples, Italy. 1-5 December 2015

MELANOMA BRIDGE 2015

KEYNOTE SPEAKER PRESENTATIONS

Molecular and immuno-advances

K1 Immunologic and metabolic consequences of PI3K/AKT/mTOR activation in melanoma

Vashisht G. Y. Nanda, Weiyi Peng, Patrick Hwu, Michael A. Davies

K2 Non-mutational adaptive changes in melanoma cells exposed to BRAF and MEK inhibitors help the establishment of drug resistance

Gennaro Ciliberto, Luigi Fattore, Debora Malpicci, Luigi Aurisicchio, Paolo Antonio Ascierto, Carlo M. Croce, Rita Mancini

K3 Tumor-intrinsic beta-catenin signaling mediates tumor-immune avoidance

Stefani Spranger, Thomas F. Gajewski

K4 Intracellular tumor antigens as a source of targets of antibody-based immunotherapy of melanoma

Yangyang Wang, Soldano Ferrone

Combination therapies

K5 Harnessing radiotherapy to improve responses to immunotherapy in cancer

Claire Vanpouille-Box, Erik Wennerberg, Karsten A. Pilones, Silvia C. Formenti, Sandra Demaria

K6 Creating a T cell-inflamed tumor microenvironment overcomes resistance to checkpoint blockade

Haidong Tang, Yang Wang, Yang-Xin Fu

K7 Biomarkers for treatment decisions?

Reinhard Dummer

K8 Combining oncolytic therapies in the era of checkpoint inhibitors

Igor Puzanov

K9 Immune checkpoint blockade for melanoma: should we combine or sequence ipilimumab and PD-1 antibody therapy?

Michael A. Postow

News in immunotherapy

K10 An update on adjuvant and neoadjuvant therapy for melanom

Ahmad Tarhini

K11 Targeting multiple inhibitory receptors in melanoma

Joe-Marc Chauvin, Ornella Pagliano, Julien Fourcade, Zhaojun Sun, Hong Wang, Cindy Sanders, John M. Kirkwood, Tseng-hui Timothy Chen, Mark Maurer, Alan J. Korman, Hassane M. Zarour

K12 Improving adoptive immune therapy using genetically engineered T cells

David F. Stroncek

Tumor microenvironment and biomarkers

K13 Myeloid cells and tumor exosomes: a crosstalk for assessing immunosuppression?

Veronica Huber, Licia Rivoltini

K14 Update on the SITC biomarker taskforce: progress and challenges

Magdalena Thurin

World-wide immunoscore task force: an update

K15 The immunoscore in colorectal cancer highlights the importance of digital scoring systems in surgical pathology

Tilman Rau, Alessandro Lugli

K16 The immunoscore: toward an integrated immunomonitoring from the diagnosis to the follow up of cancer’s patients

Franck Pagès

Economic sustainability of melanoma treatments: regulatory, health technology assessment and market access issues

K17 Nivolumab, the regulatory experience in immunotherapy

Jorge Camarero, Arantxa Sancho

K18 Evidence to optimize access for immunotherapies

Claudio Jommi

ORAL PRESENTATIONS

Molecular and immuno-advances

O1 Ipilimumab treatment results in CD4 T cell activation that is concomitant with a reduction in Tregs and MDSCs

Yago Pico de Coaña, Maria Wolodarski, Yuya Yoshimoto, Giusy Gentilcore, Isabel Poschke, Giuseppe V. Masucci, Johan Hansson, Rolf Kiessling

O2 Evaluation of prognostic and therapeutic potential of COX-2 and PD-L1 in primary and metastatic melanoma

Giosuè Scognamiglio, Francesco Sabbatino, Federica Zito Marino, Anna Maria Anniciello, Monica Cantile, Margherita Cerrone, Stefania Scala, Crescenzo D’alterio, Angela Ianaro, Giuseppe Cirino, Paolo Antonio Ascierto, Giuseppina Liguori, Gerardo Botti

O3 Vemurafenib in patients with BRAFV600 mutation–positive metastatic melanoma: final overall survival results of the BRIM-3 study

Paul B. Chapman, Caroline Robert, James Larkin, John B. Haanen, Antoni Ribas, David Hogg, Omid Hamid, Paolo Antonio Ascierto, Alessandro Testori, Paul Lorigan, Reinhard Dummer, Jeffrey A. Sosman, Keith T. Flaherty, Huibin Yue, Shelley Coleman, Ivor Caro, Axel Hauschild, Grant A. McArthur

O4 Updated survival, response and safety data in a phase 1 dose-finding study (CA209-004) of concurrent nivolumab (NIVO) and ipilimumab (IPI) in advanced melanoma

Mario Sznol, Margaret K. Callahan, Harriet Kluger, Michael A. Postow, RuthAnn Gordan, Neil H. Segal, Naiyer A. Rizvi, Alexander Lesokhin, Michael B. Atkins, John M. Kirkwood, Matthew M. Burke, Amanda Ralabate, Angel Rivera, Stephanie A. Kronenberg, Blessing Agunwamba, Mary Ruisi, Christine Horak, Joel Jiang, Jedd Wolchok

Combination therapies

O5 Efficacy and correlative biomarker analysis of the coBRIM study comparing cobimetinib (COBI) + vemurafenib (VEM) vs placebo (PBO) + VEM in advanced BRAF-mutated melanoma patients (pts)

Paolo A. Ascierto, Grant A. McArthur, James Larkin, Gabriella Liszkay, Michele Maio, Mario Mandalà, Lev Demidov, Daniil Stoyakovskiy, Luc Thomas, Luis de la Cruz-Merino, Victoria Atkinson, Caroline Dutriaux, Claus Garbe, Matthew Wongchenko, Ilsung Chang, Daniel O. Koralek, Isabelle Rooney, Yibing Yan, Antoni Ribas, Brigitte Dréno

O6 Preliminary clinical safety, tolerability and activity results from a Phase Ib study of atezolizumab (anti-PDL1) combined with vemurafenib in BRAFV600-mutant metastatic melanoma

Ryan Sullivan, Omid Hamid, Manish Patel, Stephen Hodi, Rodabe Amaria, Peter Boasberg, Jeffrey Wallin, Xian He, Edward Cha, Nicole Richie, Marcus Ballinger, Patrick Hwu

O7 Preliminary safety and efficacy data from a phase 1/2 study of epacadostat (INCB024360) in combination with pembrolizumab in patients with advanced/metastatic melanoma

Thomas F. Gajewski, Omid Hamid, David C. Smith, Todd M. Bauer, Jeffrey S. Wasser, Jason J. Luke, Ani S. Balmanoukian, David R. Kaufman, Yufan Zhao, Janet Maleski, Lance Leopold, Tara C. Gangadhar

O8 Primary analysis of MASTERKEY-265 phase 1b study of talimogene laherparepvec (T-VEC) and pembrolizumab (pembro) for unresectable stage IIIB-IV melanoma

Reinhard Dummer, Georgina V. Long, Antoni Ribas, Igor Puzanov, Olivier Michielin, Ari VanderWalde, Robert H.I. Andtbacka, Jonathan Cebon, Eugenio Fernandez, Josep Malvehy, Anthony J. Olszanski, Thomas F. Gajewski, John M. Kirkwood, Christine Gause, Lisa Chen, David R. Kaufman, Jeffrey Chou, F. Stephen Hodi

News in immunotherapy

O9 Two-year survival and safety update in patients (pts) with treatment-naïve advanced melanoma (MEL) receiving nivolumab (NIVO) or dacarbazine (DTIC) in CheckMate 066

Victoria Atkinson, Paolo A. Ascierto, Georgina V. Long, Benjamin Brady, Caroline Dutriaux, Michele Maio, Laurent Mortier, Jessica C. Hassel, Piotr Rutkowski, Catriona McNeil, Ewa Kalinka-Warzocha, Celeste Lebbé, Lars Ny, Matias Chacon, Paola Queirolo, Carmen Loquai, Parneet Cheema, Alfonso Berrocal, Karmele Mujika Eizmendi, Luis De La Cruz-Merino, Gil Bar-Sela, Christine Horak, Joel Jiang, Helene Hardy, Caroline Robert

O10 Efficacy and safety of nivolumab (NIVO) in patients (pts) with advanced melanoma (MEL) who were treated beyond progression in CheckMate 066/067

Georgina V. Long, Jeffrey S. Weber, James Larkin, Victoria Atkinson, Jean-Jacques Grob, Reinhard Dummer, Caroline Robert, Ivan Marquez-Rodas, Catriona McNeil, Henrik Schmidt, Karen Briscoe, Jean-François Baurain, F. Stephen Hodi, Jedd D. Wolchok

Tumor microenvironment and biomarkers

O11 New biomarkers for response/resistance to BRAF inhibitor therapy in metastatic melanoma

Rosamaria Pinto, Simona De Summa, Vito Michele Garrisi, Sabino Strippoli, Amalia Azzariti, Gabriella Guida, Michele Guida, Stefania Tommasi

O12 Chemokine receptor patterns in lymphocytes mirror metastatic spreading in melanoma and response to ipilimumab

Nicolas Jacquelot, David Enot, Caroline Flament, Jonathan M. Pitt, Nadège Vimond, Carolin Blattner, Takahiro Yamazaki, Maria-Paula Roberti, Marie Vetizou, Romain Daillere, Vichnou Poirier-Colame, Michaëla Semeraro, Anne Caignard, Craig L Slingluff Jr, Federica Sallusto, Sylvie Rusakiewicz, Benjamin Weide, Aurélien Marabelle, Holbrook Kohrt, Stéphane Dalle, Andréa Cavalcanti, Guido Kroemer, Anna Maria Di Giacomo, Michaele Maio, Phillip Wong, Jianda Yuan, Jedd Wolchok, Viktor Umansky, Alexander Eggermont, Laurence Zitvogel

O13 Serum levels of PD1- and CD28-positive exosomes before Ipilimumab correlate with therapeutic response in metastatic melanoma patients

Passarelli Anna, Tucci Marco, Stucci Stefania, Mannavola Francesco, Capone Mariaelena, Madonna Gabriele, Ascierto Paolo Antonio, Silvestris Franco

O14 Immunological prognostic factors in stage III melanomas

María Paula Roberti, Nicolas Jacquelot, David P Enot, Sylvie Rusakiewicz, Michaela Semeraro, Sarah Jégou, Camila Flores, Lieping Chen, Byoung S. Kwon, Ana Carrizossa Anderson, Caroline Robert, Christophe Borg, Benjamin Weide, François Aubin, Stéphane Dalle, Michele Maio, Jedd D. Wolchok, Holbrook Kohrt, Maha Ayyoub, Guido Kroemer, Aurélien Marabelle, Andréa Cavalcanti, Alexander Eggermont, Laurence Zitvogel

POSTER PRESENTATIONS

Molecular and immuno-advances

P1 Human melanoma cells resistant to B-RAF and MEK inhibition exhibit mesenchymal-like features

Anna Lisa De Presbiteris, Fabiola Gilda Cordaro, Rosa Camerlingo, Federica Fratangelo, Nicola Mozzillo, Giuseppe Pirozzi, Eduardo J. Patriarca, Paolo A. Ascierto, Emilia Caputo

P2 Anti-proliferative and pro-apoptotic effect of ABT888 on melanoma cell lines and its potential role in the treatment of melanoma resistant to B-RAF inhibitors

Federica Fratangelo, Rosa Camerlingo, Emilia Caputo, Maria Letizia Motti, Rosaria Falcone, Roberta Miceli, Mariaelena Capone, Gabriele Madonna, Domenico Mallardo, Maria Vincenza Carriero, Giuseppe Pirozzi and Paolo Antonio Ascierto

P3 Involvement of the L-cysteine/CSE/H2S pathway in human melanoma progression

Elisabetta Panza, Paola De Cicco, Chiara Armogida, Giuseppe Ercolano, Rosa Camerlingo, Giuseppe Pirozzi, Giosuè Scognamiglio, Gerardo Botti, Giuseppe Cirino, Angela Ianaro

P4 Cancer stem cell antigen revealing pattern of antibody variable region genes were defined by immunoglobulin repertoire analysis in patients with malignant melanoma

Beatrix Kotlan, Gabriella Liszkay, Miri Blank, Timea Balatoni, Judit Olasz, Emil Farkas, Andras Szollar, Akos Savolt, Maria Godeny, Orsolya Csuka, Szabolcs Horvath, Klara Eles, Yehuda Shoenfeld and Miklos Kasler

P5 Upregulation of Neuregulin-1 expression is a hallmark of adaptive response to BRAF/MEK inhibitors in melanoma

Debora Malpicci, Luigi Fattore, Susan Costantini, Francesca Capone, Paolo Antonio Ascierto, Rita Mancini, Gennaro Ciliberto

P6 HuR positively regulates migration of HTB63 melanoma cells

Farnaz Moradi, Pontus Berglund, Karin Leandersson, Rickard Linnskog, Tommy Andersson, Chandra Prakash Prasad

P7 Prolyl 4- (C-P4H) hydroxylases have opposing effects in malignant melanoma: implication in prognosis and therapy

Cristiana Lo Nigro, Laura Lattanzio, Hexiao Wang, Charlotte Proby, Nelofer Syed, Marcella Occelli, Carolina Cauchi, Marco Merlano, Catherine Harwood, Alastair Thompson, Tim Crook

P8 Urokinase receptor antagonists: novel agents for the treatment of melanoma

Maria Letizia Motti, Katia Bifulco, Vincenzo Ingangi, Michele Minopoli, Concetta Ragone, Federica Fratangelo, Antonello Pessi, Gennaro Ciliberto, Paolo Antonio Ascierto, Maria Vincenza Carriero

P9 Exosomes released by melanoma cell lines enhance chemotaxis of primary tumor cells

Francesco Mannavola, Stella D’Oronzo, Claudia Felici, Marco Tucci, Antonio Doronzo, Franco Silvestris

P10 New insights in mitochondrial metabolic reprogramming in melanoma

Anna Ferretta, Gabriella Guida, Stefania Guida, Imma Maida, Tiziana Cocco, Sabino Strippoli, Stefania Tommasi, Amalia Azzariti, Michele Guida

P11 Lenalidomide restrains the proliferation in melanoma cells through a negative regulation of their cell cycle

Stella D’Oronzo, Anna Passarelli, Claudia Felici, Marco Tucci, Davide Quaresmini, Franco Silvestris

Combination therapies

P12 Chemoimmunotherapy elicits polyfunctional anti-tumor CD8 + T cells depending on the activation of an AKT pathway sustained by ICOS

Ornella Franzese, Belinda Palermo, Cosmo Di Donna, Isabella Sperduti, MariaLaura Foddai, Helena Stabile, Angela Gismondi, Angela Santoni, Paola Nisticò

P13 Favourable toxicity profile of combined BRAF and MEK inhibitors in metastatic melanoma patients

Andrea P. Sponghini, Francesca Platini, Elena Marra, David Rondonotti, Oscar Alabiso, Maria T. Fierro, Paola Savoia, Florian Stratica, Pietro Quaglino

P14 Electrothermal bipolar vessel sealing system dissection reduces seroma output or time to drain removal following axillary and ilio-inguinal node dissection in melanoma patients: a pilot study

Di Monta Gianluca, Caracò Corrado, Di Marzo Massimiliano, Marone Ugo, Di Cecilia Maria Luisa, Mozzillo Nicola

News in immunotherapy

P15 Clinical and immunological response to ipilimumab in a metastatic melanoma patient with HIV infection

Francesco Sabbatino, Celeste Fusciello1, Antonio Marra, Rosario Guarrasi, Carlo Baldi, Rosa Russo, Di Giulio Giovanni, Vincenzo Faiola, Pio Zeppa, Stefano Pepe

P16 Immunotherapy and hypophysitis: a case report

Elisabetta Gambale, Consiglia Carella, Alessandra Di Paolo, Michele De Tursi

Tumor microenvironment and biomarkers

P17 New immuno- histochemical markers for the differential diagnosis of atypical melanocytic lesions with uncertain malignant potential

Laura Marra, Giosuè Scognamiglio, Monica Cantile, Margherita Cerrone, Fara De Murtas, Valeria Sorrentino, Anna Maria Anniciello, Gerardo Botti

P18 Utility of simultaneous measurement of three serum tumor markers in melanoma patients

Angela Sandru, Silviu Voinea, Eugenia Panaitescu, Madalina Bolovan, Adina Stanciu, Sabin Cinca

P19 The significance of various cut-off levels of melanoma inhibitory activity in evaluation of cutaneous melanoma patients

Angela Sandru, Silviu Voinea, Eugenia Panaitescu, Madalina Bolovan, Adina Stanciu, Sabin Cinca

P20 The long noncoding RNA HOTAIR is associated to metastatic progression of melanoma and it can be identified in the blood of patients with advanced disease

Chiara Botti, Giosuè Scognamiglio, Laura Marra, Gabriella Aquino, Rosaria Falcone, Annamaria Anniciello, Paolo Antonio Ascierto, Gerardo Botti, Monica Cantile

Other

P21 The effect of Sentinel Lymph Node Biopsy in melanoma mortality: timing of dissection

Cristina Fortes, Simona Mastroeni, Alessio Caggiati, Francesca Passarelli, Alba Zappalà, Maria Capuano, Riccardo Bono, Maurizio Nudo, Claudia Marino, Paola Michelozzi

P22 Epidemiological survey on related psychopathology in melanoma

Valeria De Biasio, Vincenzo C. Battarra

IMMUNOTHERAPY BRIDGE

KEYNOTE SPEAKER PRESENTATIONS

Immunotherapy beyond melanoma

K19 Predictor of response to radiation and immunotherapy

Silvia Formenti

K20 Response and resistance to PD-1 pathway blockade: clues from the tumor microenvironment

Maria Libera Ascierto, Tracee L. McMiller, Alan E. Berger, Ludmila Danilova, Robert A. Anders, George J. Netto, Haiying Xu, Theresa S. Pritchard, Jinshui Fan, Chris Cheadle, Leslie Cope, Charles G. Drake, Drew M. Pardoll, Janis M. Taube and Suzanne L. Topalian

K21 Combination immunotherapy with autologous stem cell transplantation, protein immunization, and PBMC reinfusion in myeloma patients

Sacha Gnjatic, Sarah Nataraj, Naoko Imai, Adeeb Rahman, Achim A. Jungbluth, Linda Pan, Ralph Venhaus, Andrew Park, Frédéric F. Lehmann, Nikoletta Lendvai, Adam D. Cohen, and Hearn J. Cho

K22 Anti-cancer immunity despite T cell “exhaustion”

Speiser Daniel

Immunotherapy in oncology (I-O): data from clinical trial

K23 The Checkpoint Inhibitors for the Treatment of Metastatic Non-small Cell Lung Cancer (NSCLC)

Vera Hirsh

PD-1 Blockade with Pembrolizumab in Advanced Merkel-Cell Carcinoma

BACKGROUND

Merkel-cell carcinoma is an aggressive skin cancer that is linked to exposure to ultraviolet light and the Merkel-cell polyomavirus (MCPyV). Advanced Merkel-cell carcinoma often responds to chemotherapy, but responses are transient. Blocking the programmed death 1 (PD-1) immune inhibitory pathway is of interest, because these tumors often express PD-L1, and MCPyV-specific T cells express PD-1.

METHODS

In this multicenter, phase 2, noncontrolled study, we assigned adults with advanced Merkel-cell carcinoma who had received no previous systemic therapy to receive pembrolizumab (anti-PD-1) at a dose of 2 mg per kilogram of body weight every 3 weeks. The primary end point was the objective response rate according to Response Evaluation Criteria in Solid Tumors, version 1.1. Efficacy was correlated with tumor viral status, as assessed by serologic and immunohistochemical testing.

RESULTS

A total of 26 patients received at least one dose of pembrolizumab. The objective response rate among the 25 patients with at least one evaluation during treatment was 56% (95% confidence interval [CI], 35 to 76); 4 patients had a complete response, and 10 had a partial response. With a median follow-up of 33 weeks (range, 7 to 53), relapses occurred in 2 of the 14 patients who had had a response (14%). The response duration ranged from at least 2.2 months to at least 9.7 months. The rate of progression-free survival at 6 months was 67% (95% CI, 49 to 86). A total of 17 of the 26 patients (65%) had virus-positive tumors. The response rate was 62% among patients with MCPyV-positive tumors (10 of 16 patients) and 44% among those with virus-negative tumors (4 of 9 patients). Drug-related grade 3 or 4 adverse events occurred in 15% of the patients.

CONCLUSIONS

In this study, first-line therapy with pembrolizumab in patients with advanced Merkel-cell carcinoma was associated with an objective response rate of 56%. Responses were observed in patients with virus-positive tumors and those with virus-negative tumors. (Funded by the National Cancer Institute and Merck; ClinicalTrials.gov number, NCT02267603.).

Society for immunotherapy of cancer (SITC) statement on the proposed changes to the common rule

The Common Rule is a set of ethical principles that provide guidance on the management of human subjects taking part in biomedical and behavioral research in the United States. The elements of the Common Rule were initially developed in 1981 following a revision of the Declaration of Helsinki in 1975. Most academic facilities follow the Common Rule in the regulation of clinical trials research. Recently, the government has suggested a revision of the Common Rule to include more contemporary and streamlined oversight of clinical research. In this commentary, the leadership of the Society for Immunotherapy of Cancer (SITC) provides their opinion on this plan. While the Society recognizes the considerable contribution of clinical research in supporting progress in tumor immunotherapy and supports the need for revisions to the Common Rule, there is also some concern over certain elements which may restrict access to biospecimens and clinical data at a time when high throughput technologies, computational biology and assay standardization is allowing major advances in understanding cancer biology and providing potential predictive biomarkers of immunotherapy response. The Society values its professional commitment to patients for improving clinical outcomes with tumor immunotherapy and supports continued discussion with all stakeholders before implementing changes to the Common Rule in order to ensure maximal patient protections while promoting continued clinical research at this historic time in cancer research.

Mechanism-driven biomarkers to guide immune checkpoint blockade in cancer therapy

With recent approvals for multiple therapeutic antibodies that block cytotoxic T lymphocyte associated antigen 4 (CTLA4) and programmed cell death protein 1 (PD1) in melanoma, non-small-cell lung cancer and kidney cancer, and additional immune checkpoints being targeted clinically, many questions still remain regarding the optimal use of drugs that block these checkpoint pathways. Defining biomarkers that predict therapeutic effects and adverse events is a crucial mandate, highlighted by recent approvals for two PDL1 diagnostic tests. Here, we discuss biomarkers for anti-PD1 therapy based on immunological, genetic and virological criteria. The unique biology of the CTLA4 immune checkpoint, compared with PD1, requires a different approach to biomarker development. Mechanism-based insights from such studies may guide the design of synergistic treatment combinations based on immune checkpoint blockade.

Abstract 1312: Transcriptional signatures associated with lack of response to anti-PD-1 therapy in patients with renal cell carcinoma

Background: The PD-1/PD-L1 immune checkpoint pathway limits host immune responses to cancer in the local tumor microenvironment. Monoclonal antibodies blocking PD-1 or PD-L1 have shown promising clinical results in a variety of advanced human cancers including renal cell carcinoma (RCC). We previously reported that response to anti-PD-1 therapy correlates with PD-L1 expression by tumor cells in pre-treatment biopsies. Although 20-30% of patients with metastatic RCC respond to anti-PD-1 therapy, many patients with PD-L1+ tumors still do not respond. The current study was undertaken to understand mechanisms underlying the failure of anti-PD-1 targeted therapies in patients with PD-L1+ RCC.

Methods: The specimen cohort included formalin-fixed, paraffin-embedded (FFPE) pre-treatment tumor biopsies expressing PD-L1, derived from 13 RCC patients treated with nivolumab (anti-PD-1) at a single institution [4 responders (R), 9 non-responders (NR); RECIST]. PD-L1+ specimens were defined as those having ≥5% of tumor cells with cell surface PD-L1 expression by immunohistochemistry (IHC). RNA was isolated from PD-L1+ regions on FFPE slides. Whole genome microarray profiling with cDNA-mediated Annealing, Selection, extension and Ligation (DASL) was performed. Global gene expression analysis was profiled using BRBArrayTools. Multiplex quantitative (q)RT-PCR was used to validate differential expression of genes of interest, and IHC was used to validate protein expression from select genes, in R vs. NR.

Results: Whole genome analysis revealed 234 transcripts that were differentially expressed in R vs. NR (p value ≤ 0.01, fold change ≥1.5). Ingenuity Pathway Analysis (IPA) of these transcripts showed the involvement of metabolic and immune pathways as well as genes encoding oxidation stress response molecules. Multiplex qRT-PCR for a subset of 60 differentially expressed genes validated significant over-expression of genes with metabolic functions, such as drug glucuronidation (UGT1A6/A1/A3), glucose transport (SLC23A1), and mitochondrial oxidation (AKR1C3) in NR vs. R. Conversely, R were found to overexpress immune markers such as BMP1, which has been shown to positively regulate PD-L1 expression, and CCL3 involved in leukocyte migration.

Conclusions: Although tumor PD-L1 expression is associated with an increased likelihood of response to anti-PD-1/PD-L1 therapy, tumor cell-intrinsic metabolism may contribute to treatment resistance in PD-L1+ patients. Our data suggest that overexpression of certain metabolic factors may contribute to the failure of PD-L1+ RCC to respond to PD-1 pathway blockade, while immune factors in the tumor immune microenvironment may contribute to success. Treatment strategies that co-target these factors may be needed to enhance responses to anti-PD-1 immunotherapy in RCC.

Supported by grants from Bristol-Myers Squibb and Stand Up to Cancer

Citation Format: Maria Libera Ascierto, Tracee McMiller, Alan Berger, Robert A. Anders, Chris Cheadle, Haiying Hu, Charles Drake, Drew Pardoll, Janis Taube, Suzanne L. Topalian. Transcriptional signatures associated with lack of response to anti-PD-1 therapy in patients with renal cell carcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1312. doi:10.1158/1538-7445.AM2015-1312