Capecitabine in malignant mesothelioma: a phase II trial by the Cancer and Leukemia Group B (39807)

Chemotherapy increases CDA expression and sensitizes malignant pleural mesothelioma cells to capecitabine treatment

The combination of cisplatin and pemetrexed remains the gold standard chemotherapy for malignant pleural mesothelioma (MPM), although resistance and poor response pose a significant challenge. Cytidine deaminase (CDA) is a key enzyme in the nucleotide salvage pathway and is involved in the adaptive stress response to chemotherapy. The cytidine analog capecitabine and its metabolite 5'-deoxy-5-fluorocytidine (5'-DFCR) are converted via CDA to 5-fluorouracil, which affects DNA and RNA metabolism. This study investigated a schedule-dependent treatment strategy, proposing that initial chemotherapy induces CDA expression, sensitizing cells to subsequent capecitabine treatment. Basal CDA protein expression was low in different mesothelioma cell lines but increased in the corresponding xenografts. Standard chemotherapy increased CDA protein levels in MPM cells in vitro and in vivo in a schedule-dependent manner. This was associated with epithelial-to-mesenchymal transition and with HIF-1alpha expression at the transcriptional level. In addition, pretreatment with cisplatin and pemetrexed in combination sensitized MPM xenografts to capecitabine. Analysis of a tissue microarray (TMA) consisting of samples from 98 human MPM patients revealed that most human MPM samples had negative CDA expression. While survival curves based on CDA expression in matched samples clearly separated, significance was not reached due to the limited sample size. In non-matched samples, CDA expression before but not after neoadjuvant therapy was significantly associated with worse overall survival. In conclusion, chemotherapy increases CDA expression in xenografts, which is consistent with our in vitro results in MPM and lung cancer. A subset of matched patient samples showed increased CDA expression after therapy, suggesting that a schedule-dependent treatment strategy based on chemotherapy and capecitabine may benefit a selected MPM patient population.

Validation of Progression-Free Survival as a Surrogate Endpoint for Overall Survival in Malignant Mesothelioma: Analysis of Cancer and Leukemia Group B and North Central Cancer Treatment Group (Alliance) Trials

PURPOSE

The aim of this study was to investigate whether progression-free survival (PFS) can be considered a surrogate endpoint for overall survival (OS) in malignant mesothelioma.

MATERIALS AND METHODS

Individual data were collected from 15 Cancer and Leukemia Group B (615 patients) and 2 North Central Cancer Treatment Group (101 patients) phase II trials. The effects of 5 risk factors for OS and PFS, including age, histology, performance status (PS), white blood cell count, and European Organisation for Research and Treatment of Cancer (EORTC) risk score, were used in the analysis. Individual-level surrogacy was assessed by Kendall's tau through a Clayton bivariate Copula survival (CBCS) model. Summary-level surrogacy was evaluated via the association between logarithms of the hazard ratio (log HR)-log HR_OS and log HR_PFS-measured in R² from a weighted least-square (WLS) regression model and the CBCS model.

RESULTS

The median PFS for all patients was 3.0 months (95% confidence interval [CI], 2.8-3.5 months) and the median OS was 7.2 months (95% CI, 6.5-8.0 months). Moderate correlations between PFS and OS were observed across all risk factors at the individual level, with Kendall's tau ranging from 0.46 to 0.47. The summary-level surrogacy varied among risk factors. The Copula R² ranged from 0.51 for PS to 0.78 for histology. The WLS R² ranged from 0.26 for EORTC and PS to 0.67 for age.

CONCLUSIONS

The analyses demonstrated low to moderate individual-level surrogacy between PFS and OS. At the summary level, the surrogacy between PFS and OS varied significantly across different risk factors. With a short postprogression survival and a moderate correlation between PFS and OS, there is no evidence that PFS is a valid surrogate endpoint for OS in malignant mesothelioma. The Oncologist 2017;22:189-198Implications for Practice: For better disease management and for more efficient clinical trial designs, it is important to know if progression-free survival (PFS) is a good surrogate endpoint for overall survival in malignant mesothelioma. With a relatively large database of 17 phase II trials and 716 patients from Cancer and Leukemia Group B and North Central Cancer Treatment Group, we conducted statistical analyses and found that there is no evidence to suggest that PFS is a valid surrogate endpoint for OS for malignant mesothelioma. Future research work is needed to find alternative surrogate endpoints for OS.

Chemotherapy and radiotherapy for mesothelioma

Previously considered to be rare, malignant pleural mesothelioma (MPM) is a highly aggressive tumor with an increasing incidence linked to asbestos exposure, its main etiological factor. MPM is also a very important issue because patients have usually a short survival (median <12 months) despite current treatments. Moreover an optimal treatment for MPM is not defined yet, even if ERS/ESTS experts recently provided clear and up-to-date guidelines on MPM management. These guidelines on chemotherapy and radiotherapy for mesothelioma, as well as new therapeutic developments, are presented in this chapter.

Soluble mesothelin related peptides (SMRP) and osteopontin as protein biomarkers for malignant mesothelioma: analytical validation of ELISA based assays and characterization at mRNA and protein levels

BACKGROUND

There is a need to identify reliable markers for malignant mesothelioma. Soluble mesothelin related peptides (SMRP) and osteopontin (OPN) have gained interest in recent years for this purpose.

METHODS

SMRP (Fujirebio Diagnostics Inc.) and OPN (R&D Inc.) ELISA methods were evaluated for multiple parameters. Concentrations were measured in blood from patients with mesothelioma, normal healthy volunteers, and patients with other (non-mesothelioma) cancers. In silico analysis was performed using the GeoProfiles database. At the protein level, SMRP and OPN were measured in cell culture supernatants, and values were compared in patients pre- and post-extrapleural pneumonectomy.

RESULTS

The SMRP assay demonstrates intra-assay CVs of 2.3% and 3% (at 4.6 nM and 13.7 nM, respectively), and inter-assay CVs of 3.5% and 3.7% at the same concentrations. The limit of detection (LOD) is 0.182 nM. The OPN assay demonstrates intra-assay CVs of 5.8%, 4.1%, and 5.2% (at 1.9, 5.1, and 11.1 ng/mL, respectively), and inter-assay CVs of 8.5%, 8.4%, and 12.1% at the same concentrations. The LOD is 0.032 ng/mL. Both SMRP and OPN in mesothelioma patients were significantly higher than in patients with other (non-mesothelioma) cancer and in healthy volunteers. The two markers do not appear to correlate with each other and exhibit different tissue expression patterns. Protein concentrations of these markers are highest in different sets of cell lines. Finally, SMRP but not OPN concentrations were decreased in five of seven consecutive patients after extrapleural pneumonectomy, compared to their respective pre-operative values.

CONCLUSIONS

These assays provide reliable and reproducible quantitation of SMRP and OPN proteins. Both are increased in mesothelioma patients compared to non-mesothelioma controls. However, the two analytes do not correlate with each other and show distinct expression profiles and protein expression. Concentrations of SMRP but not OPN are decreased in post-surgical samples. Our results further characterize these markers, establish assay performance characteristics, and lay the groundwork for further studies to measure these markers in blood.

An epigenetic mechanism for capecitabine resistance in mesothelioma

Mesothelioma is an uncommon malignancy whose global incidence continues to rise. The therapeutic standard for advanced disease is intravenous pemetrexed and cisplatin. The anti-folate capecitabine is significantly less effective than pemetrexed. The balance between thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), and thymidine phosphorylase (TP) is critical to the efficacy of capecitabine. DNA from mesothelioma cell lines was bisulfite treated and examined by MS-PCR, RNA was obtained for real-time PCR analysis, and protein lysates were obtained for Western immunoblot analysis. Cytotoxicity was assessed by MTT assay, comparing 5-aza-CdR pretreated or untreated cells with 5'-deoxy-5-fluorouridine (DFUR), 5-FU, and pemetrexed. Finally bisulfite sequencing of the extracellular growth factor-1 (ECGF-1) gene was performed on 4 mesothelioma samples and pericardial tissue. One of the four cell lines tested (H290) was methylated for ECGF-1. This corresponded to a lack of TP expression by real-time PCR and Western immunoblot. Treatment with 1muM 5-aza-CdR increased TP mRNA and protein expression in H290. DFUR, the substrate for TP, showed increased cytotoxicity when delivered after 5-aza-CdR exposure in the methylated cell line. There was no difference in any of the unmethylated cell lines when cells were exposed to 5-FU or pemetrexed with or without 5-aza-CdR. Patient tumor samples revealed an increased number of methylated CpG sites in ECGF-1 compared to normal pericardium. Methylation of ECGF-1, leads to transcriptional silencing of TP and may explain the lack of any effect of capecitabine, especially when compared to pemetrexed.

Management options for malignant pleural mesothelioma: clinical and cost considerations

Malignant pleural mesothelioma (MPM) is a resistant form of lung cancer that is often related to prior asbestos exposure. While surgical resection and radiotherapy techniques have been refined in recent years, neither has been proven to significantly extend patient survival compared with untreated controls. Until the release of pemetrexed in 2004, even combination chemotherapy regimens often resulted in a response rate of <20%. A recent phase III trial documented a 41.3% response rate for cisplatin plus pemetrexed. In the future, new multimodality regimens featuring novel targeted therapies directed against molecular targets, such as the vascular endothelial growth factor, hold the greatest promise for improved outcomes in MPM. The standard radiographic assessment of response to MPM therapy remains a poor surrogate for clinically relevant endpoints such as median survival. Furthermore, it is not currently known whether aggressive multimodality treatment for MPM will improve survival or quality of life above and beyond symptomatic care. Ongoing clinical trials are comparing chemotherapy and surgery with supportive care in an effort to define the role of different therapies in MPM. MPM treatment is a costly public health issue; after efficacy is proven, additional studies are needed to measure the cost effectiveness of MPM treatment regimens.

The cancer and leukemia group B respiratory committee

The Cancer and Leukemia Group B Respiratory Committee has a 30-year track record of clinical investigation in patients with small-cell lung cancer and non-small-cell lung cancer (NSCLC) and mesothelioma. The most widely recognized contributions of the Committee include the early confirmation of the role of concurrent chemoradiotherapy in LD-SCLC, the effect of combination chemotherapy followed by radiation in stage III NSCLC, the introduction of third-generation agents into concurrent chemoradiation for stage III disease, the prospective demonstration of the benefit of treating older (70 years old) and poorer performance status (performance status = 2) patients with first-line combinations for stage IV disease, and the development of the "Herndon prognostic index" to normalize patient characteristics and outcomes in sequential phase II trials of new agents in patients with mesothelioma. Many other contributions have also emerged from the Committee's clinical trials and correlative science programs. We look forward to making additional critical contributions during future decades of Cancer and Leukemia Group B Respiratory Committee research.

An overview of chemotherapy for mesothelioma

Mesothelioma is an extraordinarily challenging disease to treat. While numerous clinical trials testing various chemotherapeutic agents have been conducted over the last several decades, only recently have larger studies proven the efficacy of newer chemotherapy regimens. This article reviews the data regarding specific classes of chemotherapeutic agents. The role of treatment in various disease settings and the difficulty in assessing the benefit of that therapy is discussed. Finally, an update is provided on novel therapeutics being testing in mesothelioma.

Chemotherapy options and new advances in malignant pleural mesothelioma

Malignant pleural mesothelioma continues to be a challenging clinical problem. While traditionally, chemotherapy has been thought to be of only modest benefit to patients with this disease, novel antineoplastic agents and combination regimens incorporating these agents are gradually changing this perception. Early attempts at treatment and palliation with single agents such as doxorubicin met with low response rates and little clinical benefit. However, the recently reported clinical benefits of pemetrexed and raltitrexed in combination with cisplatin are changing the perception about the ability of chemotherapy to affect the natural history of the disease. Other combinations, including cisplatin and gemcitabine, have also shown encouraging response rates and clinical activity. Single-agent therapy with vinorelbine may provide useful palliation with low toxicity. Targeted agents developed through increased understanding of the biology of the disease, used alone or as part of multimodal therapy, may provide major clinical gains in the next few years.