Austin Duffy

Mismatch repair deficiency predicts response of solid tumors to PD-1 blockade

Predicting responses to immunotherapy Colon cancers with loss-of-function mutations in the mismatch repair (MMR) pathway have favorable responses to PD-1 blockade immunotherapy. In a phase 2 clinical trial, Le et al. showed that treatment success is not just limited to colon cancer (see the Perspective by Goswami and Sharma). They found that a wide range of different cancer types with MMR deficiency also responded to PD-1 blockade. The trial included some patients with pancreatic cancer, which is one of the deadliest forms of cancer. The clinical trial is still ongoing, and around 20% of patients have so far achieved a complete response. MMR deficiency appears to be a biomarker for predicting successful treatment outcomes for several solid tumors and indicates a new therapeutic option for patients harboring MMR-deficient cancers. Science, this issue p. 409; see also p. 358 A pan-cancer biomarker is identified that can predict successful response to cancer immunotherapy in human patients. The genomes of cancers deficient in mismatch repair contain exceptionally high numbers of somatic mutations. In a proof-of-concept study, we previously showed that colorectal cancers with mismatch repair deficiency were sensitive to immune checkpoint blockade with antibodies to programmed death receptor–1 (PD-1). We have now expanded this study to evaluate the efficacy of PD-1 blockade in patients with advanced mismatch repair–deficient cancers across 12 different tumor types. Objective radiographic responses were observed in 53% of patients, and complete responses were achieved in 21% of patients. Responses were durable, with median progression-free survival and overall survival still not reached. Functional analysis in a responding patient demonstrated rapid in vivo expansion of neoantigen-specific T cell clones that were reactive to mutant neopeptides found in the tumor. These data support the hypothesis that the large proportion of mutant neoantigens in mismatch repair–deficient cancers make them sensitive to immune checkpoint blockade, regardless of the cancers’ tissue of origin.

Second-line treatment in advanced pancreatic cancer: a comprehensive analysis of published clinical trials

BACKGROUND There is currently no standard of care for the second-line treatment of advanced pancreatic cancer. The aim of this analysis was to compare the different therapeutic approaches in this setting. METHODS We carried out a systematic analysis of second-line studies in advanced pancreatic cancer that have progressed on or following gemcitabine and published or presented from 2000 to 2012. RESULTS Forty-four clinical trials (t) were identified; of which 34 met the inclusion criteria treating an aggregate total of 1503 patients (n). Patients who received treatments (t: 33; n: 1269) had a median overall survival (OS) of 6 months compared with 2.8 months for patients who received best supportive care only (t: 2; n: 234) (P = 0.013). The gemcitabine and platinum-based combination (t: 5; n: 154) provided a median progression-free survival and OS of 4 and 6 months compared with 1.6 and 5.3 for the rest of the regimens (t: 29; n: 1349) (P = 0.059 and 0.10, respectively) and 2.9 and 5.7 for the combination of 5-fluorouracil and platinum agents (t: 12; n: 450) (P = 0.60 and 0.22, respectively). CONCLUSION(S) Although not conclusive, these data showed that the advantage of second-line chemotherapy in pancreatic cancer is very limited and there is a need for more studies.

S100A9 a new marker for monocytic human myeloid‐derived suppressor cells

Myeloid‐derived suppressor cells (MDSC) are a heterogeneous population of cells that negatively regulate the immune response during tumour progression, inflammation and infection. Only limited data are available on human MDSC because of the lack of specific markers. We have identified members of the S100 protein family – S100A8, S100A9 and S100A12 – specifically expressed in CD14+ HLA‐DR−/low MDSC. S100A9 staining in combination with anti‐CD14 could be used to identify MDSC in whole blood from patients with colon cancer. An increase in the population of CD14+ S100A9high MDSC was observed in the peripheral blood from colon cancer patients in comparison with healthy controls. Finally, nitric oxide synthase expression, a hallmark of MDSC, was induced in CD14+ S100A9high upon lipopolysaccharide/interferon‐γ stimulation. We propose S100 proteins as useful markers for the analysis and further characterization of human MDSC.

Tremelimumab in combination with ablation in patients with advanced hepatocellular carcinoma

BACKGROUND & AIMS Tremelimumab is a fully human monoclonal antibody that binds to cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) on the surface of activated T lymphocytes. Ablative therapies induce a peripheral immune response which may enhance the effect of anti-CTLA4 treatment in patients with advanced hepatocellular carcinoma (HCC). This study aimed to demonstrate whether tremelimumab could be combined safely and feasibly with ablation. METHODS Thirty-two patients with HCC were enrolled: male:female: 28:4; median age: 62 (range 36-76). Patients were given tremelimumab at two dose levels (3.5 and 10mg/kg i.v.) every 4weeks for 6 doses, followed by 3-monthly infusions until off-treatment criteria were met. On day 36, patients underwent subtotal radiofrequency ablation or chemoablation. Staging was performed by contrast-enhanced CT or MRI scan every 8weeks. RESULTS No dose-limiting toxicities were encountered. The most common toxicity was pruritus. Of the 19 evaluable patients, five (26.3%; 95% CI: 9.1-51.2%) achieved a confirmed partial response. Twelve of 14 patients with quantifiable HCV experienced a marked reduction in viral load. Six-week tumor biopsies showed a clear increase in CD8+ T cells in patients showing a clinical benefit only. Six and 12-month probabilities of tumor progression free survival for this refractory HCC population were 57.1% and 33.1% respectively, with median time to tumor progression of 7.4months (95% CI 4.7 to 19.4months). Median overall survival was 12.3months (95% CI 9.3 to 15.4months). CONCLUSIONS Tremelimumab in combination with tumor ablation is a potential new treatment for patients with advanced HCC, and leads to the accumulation of intratumoral CD8+ T cells. Positive clinical activity was seen, with a possible surrogate reduction in HCV viral load. LAY SUMMARY Studies have shown that the killing of tumors by direct methods (known as ablation) can result in the immune system being activated or switched on. The immune system could potentially also recognize and kill the cancer that is left behind. There are new drugs available known as immune checkpoint inhibitors which could enhance this effect. Here, we test one of these drugs (tremelimumab) together with ablation. CLINICAL TRIAL NUMBER ClinicalTrials.gov: NCT01853618.

Population attributable fractions of risk factors for hepatocellular carcinoma in the United States

Hepatocellular carcinoma (HCC) incidence has been increasing in the United States for several decades; and, as the incidence of hepatitis C virus (HCV) infection declines and the prevalence of metabolic disorders rises, the proportion of HCC attributable to various risk factors may be changing.

Early Tumor Progression Associated with Enhanced EGFR Signaling with Bortezomib, Cetuximab, and Radiotherapy for Head and Neck Cancer

Purpose: A phase I clinical trial and molecular correlative studies were conducted to evaluate preclinical evidence for combinatorial activity of the proteasome inhibitor bortezomib, the epidermal growth factor receptor (EGFR) inhibitor cetuximab, and radiation therapy. Experimental Design: Patients with radiotherapy-naive stage IV or recurrent squamous cell carcinoma of the head and neck (SCCHN) were studied. Escalating doses of bortezomib (0.7, 1.0, and 1.3 mg/m2) were given intravenously twice weekly on days 1, 4, 8, and 11, every 21 days, with weekly cetuximab beginning 1 week prior and concurrently with intensity-modulated radiotherapy, delivered in 2 Gy fractions to 70 to 74 Gy. Molecular effects were examined in serial serum and SCCHN tumor specimens and the cell line UMSCC-1. Results: Seven patients were accrued before the study was terminated when five of six previously untreated patients with favorable prognosis oropharyngeal SCCHN progressed within 1 year (progression-free survival = 4.8 months; 95% CI, 2.6–6.9). Three patients each received bortezomib 0.7 or 1.0 mg/m2, without dose-limiting toxicities; one patient treated at 1.3 mg/m2 was taken off study due to recurring cetuximab infusion reaction and progressive disease (PD). Expected grade 3 toxicities included radiation mucositis (n = 4), dermatitis (n = 4), and rash (n = 1). SCCHN-related cytokines increased in serial serum specimens of patients developing PD (P = 0.029). Bortezomib antagonized cetuximab- and radiation-induced cytotoxicity, degradation of EGFR, and enhanced prosurvival signal pathway activation in SCCHN tumor biopsies and UMSCC-1. Conclusions: Combining bortezomib with cetuximab and radiation therapy showed unexpected early progression, evidence for EGFR stabilization, increased prosurvival signaling, and SCCHN cytokine expression, warranting avoidance of this combination. Clin Cancer Res; 17(17); 5755–64. ©2011 AACR.

Earlier presentation and application of curative treatments in hepatocellular carcinoma

The purpose of the study was to assess the use of curative therapies for hepatocellular carcinoma (HCC) in the population. HCC treatment patterns were examined in Surveillance, Epidemiology, and End Results (SEER) 18 registries (28% of U.S.). Joinpoint regression analyses were performed to assess 2000‐2010 incidence trends by tumor size, count, and receipt of potentially curative treatments (transplantation, resection, and ablation). SEER‐Medicare data enabled evaluation of treatment patterns including receipt of sorafenib or transarterial chemoembolization (TACE) by HCC‐associated comorbidities. Diagnoses of tumors ≤5.0 cm in diameter significantly increased during 2000‐2010, surpassing diagnosis of larger tumors. Overall, 23% of cases received potentially curative treatment. Joinpoint models indicated incidence rates of treatment with curative intent increased 17.6% per year during 2000‐2005, then declined by −2.9% per year during 2005‐2010 (P < 0.001). Among HCC cases with a single tumor ≤5.0 cm and no extension beyond the liver, use of ablative therapy significantly increased during 2000‐2010. Use of invasive surgery for single tumors, regardless of size, significantly increased during the initial years of the decade, then plateaued. The group most likely to receive curative treatment in the SEER‐Medicare cases was patients with one, small tumor confined to the liver (657 of 1,597 cases, 41%), with no difference in treatment by hepatic comorbidity status (P = 0.24). A higher proportion of cases with reported liver‐associated comorbidities were, however, diagnosed with tumors ≤5.0 cm in diameter (1,745 0f 2,464, 71%) compared to patients with no reported comorbidities (996 of 2,596, 38%, P < 0.001). Conclusion: Although more HCC patients were diagnosed with early disease over time, the use of curative treatments in this patient group has recently plateaued. Efforts to identify and treat more eligible candidates for curative therapy could be beneficial. (Hepatology 2014;60:1637–1644)

The GYMSSA trial: a prospective randomized trial comparing gastrectomy, metastasectomy plus systemic therapy versus systemic therapy alone

BackgroundThe standard of care for metastatic gastric cancer (MGC) is systemic chemotherapy which leads to a median survival of 6-15 months. Survival beyond 3 years is rare. For selected groups of patients with limited MGC, retrospective studies have shown improved overall survival following gastrectomy and metastasectomies including peritoneal stripping with continuous hyperthermic peritoneal perfusion (CHPP), liver resection, and pulmonary resection. Median survival after liver resection for MGC is up to 34 months, with a five year survival rate of 24.5%. Similarly, reported median survival after pulmonary resection of MGC is 21 months with long term survival of greater than 5 years a possibility. Several case reports and small studies have documented evidence of long-term survival in select individuals who undergo CHPP for MGC.DesignThe GYMSSA trial is a prospective randomized trial for patients with MGC. It is designed to compare two therapeutic approaches: gastrectomy with metastasectomy plus systemic chemotherapy (GYMS) versus systemic chemotherapy alone (SA). Systemic therapy will be composed of the FOLFOXIRI regimen. The aim of the study is to evaluate overall survival and potential selection criteria to determine those patients who may benefit from surgery plus systemic therapy. The study will be conducted by the Surgery Branch at the National Cancer Institute (NCI), National Institutes of Health (NIH) in Bethesda, Maryland. Surgeries and followup will be done at the NCI, and chemotherapy will be given by either the local oncologist or the medical oncology branch at NCI.Trial RegistrationClinicalTrials.gov ID. NCT00941655

Comparative analysis of monocytic and granulocytic myeloid-derived suppressor cell subsets in patients with gastrointestinal malignancies

Myeloid-derived suppressor cells (MDSC) are a heterogenous population of cells comprising myeloid progenitor cells and immature myeloid cells, which have the ability to suppress the effector immune response. In humans, MDSC have not been well characterized owing to the lack of specific markers, although it is possible to broadly classify the MDSC phenotypes described in the literature as being predominantly granulocytic (expressing markers such as CD15, CD66, CD33) or monocytic (expressing CD14). In this study, we set out to perform a direct comparative analysis across both granulocytic and monocytic MDSC subsets in terms of their frequency, absolute number, and function in the peripheral blood of patients with advanced GI cancer. We also set out to determine the optimal method of sample processing given that this is an additional source of heterogeneity. Our findings demonstrate consistent changes across sample processing methods for monocytic MDSC, suggesting that reliance upon cryopreserved PBMC is acceptable. Although we did not see an increase in the population of granulocytic MDSC, these cells were found to be more suppressive than their monocytic counterparts.

Epidemiology of fibrolamellar hepatocellular carcinoma in the USA, 2000–10

We read with great interest the article by Tremosini et al 1 in Gut , which prospectively validated the use of a panel of three antibodies (glypican 3, heat shock protein 70 and glutamine synthetase) for the histopathological diagnosis of hepatocellularcarcinoma (HCC). According to the international classification of diseases for oncology,2 HCC are classified into HCC not otherwise specified (HCC-NOS), which accounts for the vast majority of HCC, fibrolamellar HCC (fHCC), scirrhous HCC, spindle cell variant HCC, clear cell HCC and pleomorphic HCC. While many studies including that by Tremosini and colleagues1 restrict their focus to HCC-NOS, we decided to study fHCC in more depth. fHCC is a rare tumour with limited clinical information available. Current data suggest that demographic attributes of fHCC cases are very different …