Autumn J. McRee

Pembrolizumab for patients with PD-L1-positive advanced gastric cancer (KEYNOTE-012): a multicentre, open-label, phase 1b trial

BACKGROUND Expression of PD-L1 has been shown to be upregulated in some patients with gastric cancer. As part of the phase 1b KEYNOTE-012 study, we aimed to assess the safety and activity of the anti-PD-1 antibody pembrolizumab in patients with PD-L1-positive recurrent or metastatic adenocarcinoma of the stomach or gastro-oesophageal junction. METHODS This study was a multicentre, open-label, phase 1b trial done at 13 cancer research centres in the USA, Israel, Japan, South Korea, and Taiwan. We enrolled patients with PD-L1-positive recurrent or metastatic adenocarcinoma of the stomach or gastro-oesophageal junction. Patients received intravenous pembrolizumab at 10 mg/kg once every 2 weeks for 24 months or until progression or unacceptable toxic effects occurred. Response was assessed every 8 weeks in accordance with Response Evaluation Criteria in Solid Tumors version 1.1. The primary objectives were safety in patients who received at least one dose of pembrolizumab and the proportion of patients achieving overall responses in patients who received at least one pembrolizumab dose and who either had a post-baseline scan or who discontinued therapy because of clinical disease progression or a treatment-related adverse event before the first post-baseline scan. The study is registered with ClinicalTrials.gov, number NCT01848834, and is ongoing but no longer enrolling patients. FINDINGS From Oct 23, 2013, to May 5, 2014, 39 patients were enrolled. 36 were evaluable for response by central assessment. Eight (22%, 95% CI 10-39) patients were judged to have had an overall response at central review; all responses were partial. All 39 patients were included in the safety analyses. Five (13%) patients had a total of six grade 3 or 4 treatment-related adverse events, consisting of two cases of grade 3 fatigue, one case each of grade 3 pemphigoid, grade 3 hypothyroidism, and grade 3 peripheral sensory neuropathy, and one case of grade 4 pneumonitis. No treatment-related deaths occurred. INTERPRETATION In this population of patients with recurrent or metastatic PD-L1-positive gastric cancer, pembrolizumab had a manageable toxicity profile and promising antitumour activity, warranting further study in phase 2 and 3 trials. FUNDING Merck & Co.

Integrative Genomic Analysis of Cholangiocarcinoma Identifies Distinct IDH-Mutant Molecular Profiles

Summary Cholangiocarcinoma (CCA) is an aggressive malignancy of the bile ducts, with poor prognosis and limited treatment options. Here, we describe the integrated analysis of somatic mutations, RNA expression, copy number, and DNA methylation by The Cancer Genome Atlas of a set of predominantly intrahepatic CCA cases and propose a molecular classification scheme. We identified an IDH mutant-enriched subtype with distinct molecular features including low expression of chromatin modifiers, elevated expression of mitochondrial genes, and increased mitochondrial DNA copy number. Leveraging the multi-platform data, we observed that ARID1A exhibited DNA hypermethylation and decreased expression in the IDH mutant subtype. More broadly, we found that IDH mutations are associated with an expanded histological spectrum of liver tumors with molecular features that stratify with CCA. Our studies reveal insights into the molecular pathogenesis and heterogeneity of cholangiocarcinoma and provide classification information of potential therapeutic significance.

Combined BRAF, EGFR, and MEK Inhibition in Patients with BRAFV600E-Mutant Colorectal Cancer

Although BRAF inhibitor monotherapy yields response rates >50% in BRAFV600-mutant melanoma, only approximately 5% of patients with BRAFV600E colorectal cancer respond. Preclinical studies suggest that the lack of efficacy in BRAFV600E colorectal cancer is due to adaptive feedback reactivation of MAPK signaling, often mediated by EGFR. This clinical trial evaluated BRAF and EGFR inhibition with dabrafenib (D) + panitumumab (P) ± MEK inhibition with trametinib (T) to achieve greater MAPK suppression and improved efficacy in 142 patients with BRAFV600E colorectal cancer. Confirmed response rates for D+P, D+T+P, and T+P were 10%, 21%, and 0%, respectively. Pharmacodynamic analysis of paired pretreatment and on-treatment biopsies found that efficacy of D+T+P correlated with increased MAPK suppression. Serial cell-free DNA analysis revealed additional correlates of response and emergence of KRAS and NRAS mutations on disease progression. Thus, targeting adaptive feedback pathways in BRAFV600E colorectal cancer can improve efficacy, but MAPK reactivation remains an important primary and acquired resistance mechanism.Significance: This trial demonstrates that combined BRAF + EGFR + MEK inhibition is tolerable, with promising activity in patients with BRAFV600E colorectal cancer. Our findings highlight the MAPK pathway as a critical target in BRAFV600E colorectal cancer and the need to optimize strategies inhibiting this pathway to overcome both primary and acquired resistance. Cancer Discov; 8(4); 428-43. ©2018 AACR.See related commentary by Janku, p. 389See related article by Hazar-Rethinam et al., p. 417This article is highlighted in the In This Issue feature, p. 371.

A Landscape of Therapeutic Cooperativity in KRAS Mutant Cancers Reveals Principles for Controlling Tumor Evolution

Combinatorial inhibition of effector and feedback pathways is a promising treatment strategy for KRAS mutant cancers. However, the particular pathways that should be targeted to optimize therapeutic responses are unclear. Using CRISPR/Cas9, we systematically mapped the pathways whose inhibition cooperates with drugs targeting the KRAS effectors MEK, ERK, and PI3K. By performing 70 screens in models of KRAS mutant colorectal, lung, ovarian, and pancreas cancers, we uncovered universal and tissue-specific sensitizing combinations involving inhibitors of cell cycle, metabolism, growth signaling, chromatin regulation, and transcription. Furthermore, these screens revealed secondary genetic modifiers of sensitivity, yielding a SRC inhibitor-based combination therapy for KRAS/PIK3CA double-mutant colorectal cancers (CRCs) with clinical potential. Surprisingly, acquired resistance to combinations of growth signaling pathway inhibitors develops rapidly following treatment, but by targeting signaling feedback or apoptotic priming, it is possible to construct three-drug combinations that greatly delay its emergence.

Optimal management of metastatic colorectal cancer: Current status

Colorectal cancer remains one of the most common causes of cancer death in the US, with approximately a quarter of patients presenting with metastatic disease at the time of diagnosis. Recent advances over the past 2 decades have increased the repertoire of chemotherapeutic agents for this disease and extended median overall survival to more than 20 months. An increasing body of evidence also supports the addition of targeted agents, those directed towards vascular endothelial growth factor and epidermal growth factor receptors, to expand treatment options for patients with metastatic disease. Ongoing trials are exploring the optimal combinations of these drugs as well as promising new investigational agents that take advantage of the genetic aberrations that drive tumour biology. This review aims to summarize the pertinent data on available cytotoxic and biological agents used to extend survival in metastatic colorectal cancer patients and provide a modern approach to treatment strategies while acknowledging the areas of controversy on which future clinical trials should be based.

Checkpoint inhibition for colorectal cancer: progress and possibilities

Colorectal cancer (CRC) remains the third most common cause of cancer death in the USA. Despite an increase in the repertoire of treatment options available for CRC, median overall survival has plateaued at approximately 2.5 years. Strategies that engage the patients native immune system to overcome checkpoint inhibition have proven to be promising in subsets of CRCs, specifically those with mismatch repair deficiency. Further studies are required to determine combinations of standard therapies with immunotherapy drugs and to discover the best biomarkers to predict response. This review provides insight into the progress made in treating patients with advanced CRC with immunotherapeutics and the areas that demand further research to make these drugs more effective in this patient population.

Chemoradiation therapy in the management of gastrointestinal malignancies

Concurrent administration of chemotherapy and radiotherapy has been increasingly used in cancer treatment, leading to improvements in survival as well as quality of life. Currently, it is a feasible preference, often regarded as the standard therapeutic option, for many locally confined solid tumors, including anal, bladder, cervical, esophageal, gastric, head and neck, lung, pancreatic and rectal cancers. In patients with these tumors, combined modality therapy improves local tumor control and survival while, in some instances, obviating the need for surgical removal of the organ of origin. The scientific rationale for the use of chemoradiation derives from the preclinical and clinical observations of synergistic interactions between radiotherapy and chemotherapy. When chemotherapy and radiotherapy are administered together, the chemotherapeutic agents can sensitize the cancer cells to the effects of ionizing radiation, leading to increased tumor-killing effects within the radiotherapy field. This, in turn, can improve local control of the primary tumor and, in some cancers, render surgical resection unnecessary. In other cases, patients with tumors that were initially considered unresectable are able to undergo curative interventions after completing chemoradiation. The chemotherapy component can address any potential micrometastatic disease that, without therapy, leads to an increased risk of distant recurrence. A large body of evidence exists that supports the use of chemoradiotherapy in gastrointestinal cancers. In fact, one of the first tumor types in which the superior efficacy of chemoradiation was described was anal cancer. Since then, chemoradiotherapy has been explored in other gastrointestinal malignancies with superior outcomes when compared with either radiation or chemotherapy alone. This article aims to recapitulate the clinical evidence supporting the use of chemoradiotherapy in a variety of gastrointestinal tumor types.

Multidisciplinary Approach to the Management of Esophageal Malignancies

IntroductionA multidisciplinary approach in the management of complex malignancies is becoming more common, and likewise, adopting such an approach to the care of patients with locally advanced esophageal is recommended in order to optimize clinical outcomes.MethodsIn this review, we discuss both the surgical and medical oncology perspectives in the management of patients with locally advanced esophageal cancer. We review the data supporting the current standard-of-care approach, namely trimodality therapy with neoadjuvant chemo-radiotherapy followed by surgery. Other aspects of managing these patients including the control of dysphagia and pain as well as nutritional support are discussed. Finally, we review data that support the importance of incorporating a multidisciplinary streamlined approach in the management of these patients.ResultsRather than having patients see each provider separately, a multidisciplinary approach to esophageal cancer allows for the seamless flow of communication and proactive management of the patient’s symptoms. These benefits include increasing the likelihood of evidence-based decision making, shorter time to treatment, and increased patient quality of life, all of which can result in improved patient outcomes.ConclusionThe use of a multidisciplinary team can lead to a more accurate staging paradigm and thereby, better management decisions that translate to improved clinical outcomes. Therefore, optimizing the multidisciplinary approach for the care of patients with locally advanced esophageal cancer is essential for successful and individualized patient care.

A Phase I Trial of the PI3K Inhibitor Buparlisib Combined With Capecitabine in Patients With Metastatic Breast Cancer

&NA; We report the results from a phase I study of buparlisib, an oral pan‐class I phosphotidyinositol‐3‐kinase inhibitor, combined with capecitabine in patients with metastatic breast cancer. The maximum tolerated dose of the combination was buparlisib 100 mg daily and capecitabine 1000 mg/m2 twice daily. A complete response was seen in 1 patient with a basal‐like tumor. Pharmacokinetic analysis suggested that a pharmacokinetic interaction might exist between the 2 agents. Background: Buparlisib is an oral pan‐class I phosphotidyinositol‐3‐kinase (PI3K) inhibitor. The present phase I study evaluated the safety, pharmacokinetics, and efficacy of buparlisib with capecitabine in patients with metastatic breast cancer. Patients and Methods: Patients received buparlisib once daily (range, 50 to 100 mg) for 3 weeks with capecitabine twice daily (range, 1000 to 1250 mg/m2) for 2 weeks with a 1‐week break. Dose escalation used a traditional “3 + 3” design with standard definitions of dose‐limiting toxicity (DLT) and maximum tolerated dose. Results: Of the 25 patients enrolled, 23 were evaluable for DLT and 17 were evaluable for response. The maximum tolerated dose of the combination was buparlisib 100 mg daily and capecitabine 1000 mg/m2 twice daily. DLTs included grade 3 hyperglycemia and grade 3 confusion. The most common grade 3 toxicities were diarrhea and elevation of aspartate aminotransferase and alanine transaminase. One patient exhibited a complete response to treatment and four had a confirmed partial response. In cohorts 3 and 4, in which the buparlisib dose remained constant but the capecitabine dose was increased, significant increases in the buparlisib plasma concentration were noted. Conclusion: The combination of buparlisib with capecitabine in patients with metastatic breast cancer was generally well‐tolerated, with several patients demonstrating prolonged responses. Unexpectedly low rates of PIK3CA mutations (3 of 17) were seen, and only 2 of 7 tumors with subtyping were luminal, making exploration of these putative predictive markers impossible. Further study of the combination is not unreasonable, with expanded pharmacokinetics and sequencing analysis to better elucidate potential drug–drug interactions and more accurate predictive biomarkers of response.