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Dive into the research topics where Jonathan Shamash is active.

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Featured researches published by Jonathan Shamash.


Journal of Clinical Oncology | 2009

Highly Active Antiretroviral Therapy and the Incidence of Non–AIDS-Defining Cancers in People With HIV Infection

Thomas Powles; David Robinson; Justin Stebbing; Jonathan Shamash; Mark Nelson; Brian Gazzard; Sundhiya Mandelia; Henrik Møller; Mark Bower

PURPOSE The effect of highly active antiretroviral therapy (HAART) on the incidence of non-AIDS-defining cancers (NADCs) is unclear. METHODS We have investigated the occurrence of NADCs in a prospective cohort of 11,112 HIV-positive individuals, with 71,687 patient-years of follow-up. Standardized incidence ratios (SIRs) were calculated using general population incidence data. We investigated the effect of calendar period, HIV parameters, and immunologic and treatment-related factors on the incidence of these cancers using univariate and multivariate analyses. RESULTS The SIR for all NADCs was 1.96 (95% CI, 1.66 to 2.29). There was no significant excess in incidence in the pre-HAART era (1983 to 1995; SIR, 0.95; 95% CI, 0.58 to 1.47). However, the incidence increased in the early HAART period (1996 to 2001) and remains elevated in the most recent established HAART period (2002 to 2007; SIR, 2.05; 95% CI, 1.51 to 2.72, and SIR 2.49; 95% CI, 2.00 to 3.07, respectively). Multivariate analysis showed that use of HAART (hazard ratio [HR] = 1.64; 95% CI, 1.13 to 2.39) and a nadir CD4 count less than 200/microL (HR = 1.67; 95% CI, 1.10 to 2.54) were associated with an increased risk. Only the non-nucleoside reverse transcriptase inhibitors (NNRTIs) were associated with a significantly increased risk of NADCs (HR = 1.45; 95% CI, 1.01 to 2.08). Much of this association was attributable to an increased risk of Hodgkins lymphoma with NNRTIs (HR = 2.20; 95% CI, 1.03 to 4.69). CONCLUSION Since the introduction of HAART, there has been a significantly increased risk of NADCs, which has now stabilized. A number of factors are associated with this increased risk, including HAART use. There may be an association between the use of NNRTIs and the development of Hodgkins lymphoma.


Journal of Clinical Oncology | 2000

Phase II Study of Vinorelbine in Patients With Malignant Pleural Mesothelioma

Jeremy Steele; Jonathan Shamash; Marie T. Evans; Nicole H. Gower; Marc Tischkowitz; Robin M. Rudd

PURPOSE To evaluate the response rate and impact on quality of life of vinorelbine given as cycles of 30 mg/m(2) weekly for 6 weeks to patients with malignant pleural mesothelioma. PATIENTS AND METHODS Twenty-nine patients with histologically proven malignant pleural mesothelioma were enrolled (26 male patients and three female patients; median age, 58 years [range, 29 to 77 years]). Seventeen patients had epithelioid tumors, two had sarcomatoid tumors, and 10 had biphasic tumors. The International Mesothelioma Interest Group staging system was used: one patient had stage Ib disease, 10 had stage II disease, eight had stage III disease, and 10 had stage IV disease. Patients were treated with weekly injections of vinorelbine 30 mg/m(2). A cycle consisted of six weekly injections. The new guidelines to evaluate the response to treatment in solid tumors were used. Responses were measured by spiral computed tomography scan. RESULTS All twenty-nine patients had measurable disease and were assessed for response. There were seven partial responses (24% [95% confidence interval, 10% to 44%]), 16 patients had stable disease (55%), and six patients had disease progression on therapy (21%). The median number of vinorelbine injections was 12 (range, 2 to 30). Quality-of-life analyses showed a benefit for vinorelbine therapy. CONCLUSION Vinorelbine shows promise in the palliation of patients with malignant pleural mesothelioma. The relatively low toxicity of the drug suggests that trials of vinorelbine in combination with other agents should be feasible.


Lung Cancer | 2009

The efficacy and safety of weekly vinorelbine in relapsed malignant pleural mesothelioma.

Justin Stebbing; Thomas Powles; Kirsty McPherson; Jonathan Shamash; Paula Wells; Michael T. Sheaff; Sarah Slater; Robin M. Rudd; Dean A. Fennell; Jeremy Steele

Malignant pleural mesothelioma (MPM) is a rapidly progressive invariably lethal tumor. Treatment options remain limited and the outcome in relapsed disease is poor warranting new therapeutic options. Following our previous experience in the first-line setting, we conducted a phase 2 open-label non-comparative study to assess the safety and efficacy of weekly vinorelbine chemotherapy, each cycle consisting of 30 mg/m(2) for 6 weeks, in patients with previous exposure to chemotherapy. In 63 individuals with relapsed MPM who had not received previous vinorelbine, we observed an objective response rate of 16% and an overall survival of 9.6 months (95% confidence interval 7.3-11.8 months). The main grade III/IV toxicity observed was neutropenia and toxicity was similar to weekly vinorelbine when used in the first-line setting. Weekly vinorelbine appeared to have a reasonable response rate with an acceptable toxicity profile in the second-line treatment of MPM. Its use should be prospectively evaluated in a randomised trial in the first or second-line therapy of MPM.


Clinical Cancer Research | 2011

Sequential FDG-PET/CT as a Biomarker of Response to Sunitinib in Metastatic Clear Cell Renal Cancer

Irfan Kayani; Norbert Avril; Simon Chowdhury; Andrea G. Rockall; Anju Sahdev; Paul Nathan; Peter Wilson; Jonathan Shamash; Kevin Sharpe; Louise Lim; John Dickson; Peter J. Ell; Andrew R. Reynolds; Thomas Powles

Purpose: To test the hypothesis that sequential 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) is a correlative marker in metastatic clear cell renal cancer (mRCC), patients were treated with sunitinib. Three sequential scans were conducted to determine whether the timing of the investigation was relevant. Experimental Design: Forty-four untreated mRCC patients were enrolled into this prospective phase II study. 18F-FDG-PET/CT scans were conducted before (n = 44) and after 4 weeks (n = 43) and 16 weeks (n = 40) of sunitinib given at standard doses. The primary endpoint was to correlate FDG-PET/CT response (20% reduction in SUVmax) at 4 and 16 weeks with overall survival (OS). Results: Forty-three (98%) patients had FDG-PET/CT avid lesions at diagnosis (median SUVmax = 6.8, range: <2.5–18.4). In multivariate analysis, a high SUVmax and an increased number of PET-positive lesions correlated with shorter OS [HR: 3.30 (95% CI: 1.36–8.45) and 3.67 (95% CI: 1.43–9.39), respectively]. After 4 weeks of sunitinib, a metabolic response occurred in 24 (57%) patients, but this did not correlate with progression-free survival (HR for responders = 0.87; 95% CI: 0.40–1.99) or OS (HR for responders = 0.80; 95% CI: 0.34–1.85). After 16 weeks of treatment, disease progression on FDG-PET/CT occurred in 28% (n = 12) patients which correlated with a decreased OS and PFS [HR = 5.96 (95% CI: 2.43–19.02) and HR = 12.13 (95% CI: 3.72–46.45), respectively]. Conclusions: Baseline FDG-PET/CT yields prognostic significant data. FDG-PET/CT responses occur in the majority of patients after 4 weeks of therapy; however, it is not until 16 weeks when the results become prognostically significant. Clin Cancer Res; 17(18); 6021–8. ©2011 AACR.


Journal of Clinical Oncology | 2005

Statistical Validation of the EORTC Prognostic Model for Malignant Pleural Mesothelioma Based on Three Consecutive Phase II Trials

Dean A. Fennell; Amit Parmar; Jonathan Shamash; Marie T. Evans; Michael Sheaff; Richard Sylvester; Kevin Dhaliwal; Nicole H. Gower; Jeremy Steele; Robin M. Rudd

PURPOSE Malignant pleural mesothelioma (MPM) carries a poor prognosis due to chemoresistance. The European Organisation for Research and Treatment of Cancer (EORTC) prognostic model was reported to predict survival in MPM. Our retrospective analysis set out to test the validity of the model as a prognostic tool in patients treated in three phase II trials at St Bartholomews Hospital (London, United Kingdom) between 1999 and 2003. PATIENTS AND METHODS A total of 145 patients were treated in three phase II trials; vinorelbine (VIN; 70 patients), vinorelbine/oxaliplatin (VO; 26 patients), and irinotecan/cisplatin/mitomycin C (IPM; 49 patients). Two subgroups, high-risk and low-risk, were defined by EORTC prognostic score (EPS). EPS was determined by a five-parameter model incorporating age, sex, histology, probability of diagnosis, and leukocyte count. An EPS cutoff of less than 1.27 (low risk) or more than 1.27 (high risk) was used to stratify Kaplan-Meier survival curves. Each of the EPS variables exhibited either trends or significant stratification of overall survival (OS). RESULTS Multivariate analysis confirmed leukocyte count, Eastern Cooperative Oncology Group performance status, and sarcomatous histology as independent prognostic variables. EPS stratified OS in both individual and pooled trial datasets. No association between objective tumor response and EPS classification was identified by multinomial logistic regression. EPS stratified progression-free survival for the VO and IPM cohorts, but not for VIN. CONCLUSION This study validates the EPS system as a robust tool for stratifying small trials into low- and high-risk subgroups. EPS should facilitate patient selection and analysis in randomized clinical trials.


Annals of Oncology | 2011

The safety and efficacy of sunitinib before planned nephrectomy in metastatic clear cell renal cancer

Thomas Powles; Irfan Kayani; Christian U. Blank; S. Chowdhury; Simon Horenblas; John Peters; Jonathan Shamash; Naveed Sarwar; K. Boletti; A. Sadev; T. O'Brien; Daniel M. Berney; Luis Beltran; John B. A. G. Haanen; Axel Bex

Background: The safety and efficacy of upfront sunitinib, before nephrectomy in metastatic clear cell renal cancer (mCRC), has not been prospectively evaluated. Methods: Two prospective single-arm phase II studies investigated either two cycles (study A: n = 19) or three cycles (study B: n = 33) of sunitinib before nephrectomy in mCRC. Results: Overall, 38 of 52 (73%) of patients obtained clinical benefit (by RECIST) before surgery. The partial response rate of the primary tumour was 6% [median reduction in longest diameter of 12% (range 8%−35%)]. No patients became ineligible due to local progression of disease. A nephrectomy was carried out in 37 (71%) of patients. Necrosis (>50%) was a prominent feature at nephrectomy in 49%. Surgical complications (Clavien–Dindo classification) occurred in 10 (27%) patients, including one death (3%). The median blood loss and surgical time were 725 (90–4200) ml and 189 (70–420) min, respectively. The median progression-free survival was 8 months (95% confidence interval 6–15 months). A comparison of two versus three pre-surgery cycles showed no significant difference in terms of surgical complications or efficacy. Conclusions: Nephrectomy after upfront sunitinib can be carried out safely. It obtains control of disease. Randomised studies are required to address if this approach is beneficial.


European Urology | 2011

The Outcome of Patients Treated with Sunitinib Prior to Planned Nephrectomy in Metastatic Clear Cell Renal Cancer

Thomas Powles; Christian U. Blank; Simon Chowdhury; Simon Horenblas; John Peters; Jonathan Shamash; Naveed Sarwar; Ekaterini Boleti; Anju Sahdev; Tim O'Brien; Daniel M. Berney; Luis Beltran; Paul Nathan; John B. A. G. Haanen; Axel Bex

BACKGROUND The role of cytoreductive nephrectomy in metastatic clear cell renal cell carcinoma (ccRCC) is controversial. OBJECTIVE To determine the outcome of patients with metastatic ccRCC who receive sunitinib prior to planned nephrectomy. DESIGN, SETTING, AND PARTICIPANTS The study combined the data from two prospective phase 2 studies that assessed upfront sunitinib (12-16 wk) prior to nephrectomy in previously untreated patients with metastatic renal cell carcinoma (RCC). Sunitinib was discontinued during the perioperative period (median: 29 d). INTERVENTION Sunitinib 50mg in six weekly cycles (4 wk on, 2 wk off). MEASUREMENTS Progression-free (PFS) and overall survival (OS) using the Kaplan-Meier method. RESULTS AND LIMITATIONS Twenty-one patients (32%) had Memorial Sloan-Kettering Cancer Centre (MSKCC) poor-risk disease; 45 (68%) had intermediate-risk disease. Nephrectomy was not performed in 19 (29%), most commonly due to disease progression (n = 12). The PFS for the cohort was 6.3 mo (95% confidence interval [CI], 5.1-8.5). Seventeen (36%) patients progressed during the treatment break, 13 (76%) of whom stabilised upon reinitiating of sunitinib. The OS for the cohort was 15.2 mo (95% CI, 10.3-NA). The OS for the intermediate MSKCC risk group was significantly longer than that for the poor-risk group (26.0 mo [95% CI, 13.6-NA] and 9.0 mo [95% CI, 5.8-20.5], respectively; p < 0.01). In multivariate analysis, progression of disease prior to planned nephrectomy (hazard ratio [HR]: 5.34; 95% CI, 3.17-13.27), high Fuhrman grade (HR 3.27; 95% CI, 1.38-7.72), and MSKCC poor risk at diagnosis (HR 4.75; 95% CI, 2.05-11.02) were associated with short survival (p < 0.01). However, in the absence of randomised studies it is not possible to determine if this approach is beneficial. CONCLUSIONS Upfront sunitinib prior to planned nephrectomy in intermediate-risk disease is associated with a median survival of >2 yr despite frequent progression during treatment break. Progression in metastatic sites prior to planned surgery and MSKCC poor-risk disease was associated with a poor outcome.


Oncogene | 2004

Effect of haemopoietic growth factors on cancer cell lines and their role in chemosensitivity

Wai M. Liu; Thomas Powles; Jonathan Shamash; David Propper; Tim Oliver; Simon Joel

The recombinant growth factors (GFs) erythropoietin (Epo) and granulocyte–macrophage colony stimulating factor (GM-CSF) have important roles in the management of cancer patients. However, the effects of these GFs at a cellular level are not well understood. We examined the effect of GFs alone, and in combination with cytotoxic chemotherapy, in a panel of seven cell lines. Flow cytometric analysis showed varying levels of receptor expression, which correlated with phosphorylated MAPK expression. Additionally, there were also concomitant increases in BCL-2 protein levels in those cells with high levels of MAPK activation. Although culturing cells with Epo or GM-CSF did not alter cell viability by themselves, GF pretreatment in cell lines expressing higher receptor levels resulted in a reduced magnitude of cell kill following exposure to cytotoxic IC50 concentrations of cisplatin. Subsequent co-culture with either the MEK inhibitor U0126 or the GM-CSF antagonist E21R negated this induced resistance to cytotoxic chemotherapy, confirming the importance of the GF receptor as well as MAPK in mediating these effects. These results suggest that the use of GFs during chemotherapy may be detrimental in those cancers expressing higher levels of the specific receptor. Conversely, our results also suggest that GFs are safe to use in chemotherapeutic regimens if the cancer cells do not overexpress the particular receptor.


PLOS ONE | 2015

Optimization and Evaluation of a Novel Size Based Circulating Tumor Cell Isolation System

Lei Xu; Xueying Mao; Ahmet Imrali; Ferrial Syed; Katherine Mutsvangwa; Daniel M. Berney; Paul Cathcart; John Hines; Jonathan Shamash; Yong-Jie Lu

Isolation of circulating tumor cells (CTCs) from peripheral blood has the potential to provide a far easier “liquid biopsy” than tumor tissue biopsies, to monitor tumor cell populations during disease progression and in response to therapies. Many CTC isolation technologies have been developed. We optimized the Parsortix system, an epitope independent, size and compressibility-based platform for CTCs isolation, making it possible to harvest CTCs at the speed and sample volume comparable to standard CellSearch system. We captured more than half of cancer cells from different cancer cell lines spiked in blood samples from healthy donors using this system. Cell loss during immunostaining of cells transferred and fixed on the slides is a major problem for analyzing rare cell samples. We developed a novel cell transfer and fixation method to retain >90% of cells on the slide after the immunofluorescence process without affecting signal strength and specificity. Using this optimized method, we evaluated the Parsortix system for CTC harvest in prostate cancer patients in comparison to immunobead based CTC isolation systems IsoFlux and CellSearch. We harvested a similar number (p = 0.33) of cytokeratin (CK) positive CTCs using Parsortix and IsoFlux from 7.5 mL blood samples of 10 prostate cancer patients (an average of 33.8 and 37.6 respectively). The purity of the CTCs harvested by Parsortix at 3.1% was significantly higher than IsoFlux at 1.0% (p = 0.02). Parsortix harvested significantly more CK positive CTCs than CellSearch (p = 0.04) in seven prostate cancer patient samples, where both systems were utilized (an average of 32.1 and 10.1 respectively). We also captured CTC clusters using Parsortix. Using four-color immunofluorescence we found that 85.8% of PC3 cells expressed EpCAM, 91.7% expressed CK and 2.5% cells lacked both epithelial markers. Interestingly, 95.6% of PC3 cells expressed Vimentin, including those cells that lacked both epithelial marker expression, indicating epithelial-to-mesenchymal transition. CK-positive/Vimentin-positive/CD45-negative, and CK-negative/Vimentin-positive/CD45-negative cells were also observed in four of five prostate cancer patients but rarely in three healthy controls, indicating that Parsortix harvests CTCs with both epithelial and mesenchymal features. We also demonstrated using PC3 and DU145 spiking experiment that Parsortix harvested cells were viable for cell culture.


Journal of Clinical Oncology | 2003

Multicenter Study of Human Immunodeficiency Virus–Related Germ Cell Tumors

Thomas Powles; Mark Bower; Gedske Daugaard; Jonathan Shamash; A. De Ruiter; M Johnson; M Fisher; Jane Anderson; Sundhiya Mandalia; Justin Stebbing; Mark Nelson; B Gazzard; T. Oliver

PURPOSE Testicular germ cell tumors (GCT) occur at increased frequency in men with human immunodeficiency virus (HIV). This multicenter study addresses the characteristics of these tumors. PATIENTS AND METHODS Patients with HIV-related GCT were identified from six HIV treatment centers. The incidence was calculated from the center with the most complete linked oncology and HIV databases. RESULTS Thirty-five patients with HIV-related GCT were identified. The median age at GCT diagnosis was 34 years (range, 27 to 64 years). The median CD4 cell count was 315/mm3 (range, 90 to 960/mm3) at this time. The histologic classification was seminoma in 26 patients (74%) and nonseminomatous GCT in nine patients (26%). Twenty-one patients (60%) had stage I disease and 14 patients had metastatic disease. Overall six patients relapsed, three died from GCT, and seven died from HIV disease, resulting in a 2-year overall survival rate of 81%. HIV-related seminoma occurred more frequently than in the age- and sex-matched HIV-negative population, with a relative risk of 5.4 (95% confidence interval, 3.35 to 8.10); however, nonseminomatous GCT did not occur more frequently, and there was no change in the incidence of GCT since the introduction of highly active antiretroviral therapy. CONCLUSION Testicular seminoma occurs significantly more frequently in HIV-positive men than in the matched control population. Patients with HIV-related GCTs present and should be treated in a similar manner to those in the HIV-negative population. After a median follow-up of 4.6 years, 9% of the patients died from GCT. Most of the mortality relates to HIV infection.

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Thomas Powles

Queen Mary University of London

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Peter Wilson

St Bartholomew's Hospital

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Daniel M. Berney

Queen Mary University of London

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Wendy Ansell

St Bartholomew's Hospital

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Jeremy Steele

St Bartholomew's Hospital

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Robin M. Rudd

St Bartholomew's Hospital

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T. Oliver

St Bartholomew's Hospital

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