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Dive into the research topics where Jonathan E. Dowell is active.

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Featured researches published by Jonathan E. Dowell.


Journal of Clinical Oncology | 2014

Phase II Trial of Stereotactic Body Radiation Therapy Combined With Erlotinib for Patients With Limited but Progressive Metastatic Non–Small-Cell Lung Cancer

Puneeth Iyengar; Brian D. Kavanagh; Zabi Wardak; I. Smith; Chul Ahn; David E. Gerber; Jonathan E. Dowell; Randall S. Hughes; Ramzi Abdulrahman; D. Ross Camidge; Laurie E. Gaspar; Robert C. Doebele; Paul A. Bunn; Hak Choy; Robert D. Timmerman

PURPOSE Patients with stage IV non-small-cell lung cancer (NSCLC) who progress through first-line therapy have poor progression-free survival (PFS) and overall survival (OS), most commonly failing in original sites of gross disease. Cytoreduction with stereotactic body radiation therapy (SBRT) may help systemic agents delay relapse. PATIENTS AND METHODS Patients in our single arm phase II study had stage IV NSCLC with no more than six sites of extracranial disease who failed early systemic chemotherapy and were able to receive SBRT and concurrent erlotinib until disease progression. After erlotinib commencement, SBRT with equipotent fractionation was delivered to all sites of disease. PFS, OS, and other end points were evaluated. RESULTS Twenty-four patients (13 men and 11 women) with a median age of 67 years (range, 56-86 years) were enrolled with median follow-up of 11.6 months. All patients had progressed through platinum-based chemotherapy. A total of 52 sites were treated with 16 of 24 patients receiving SBRT to more than one site. Lung parenchyma was most often irradiated. Median PFS was 14.7 months, and median OS was 20.4 months. Most patients progressed in new distant sites with only three of 47 measurable lesions recurring within the SBRT field. Two grade 3 toxicities were radiation related. Zero of 13 patients tested were positive for an EGFR mutation. CONCLUSION Use of SBRT with erlotinib for unselected patients with stage IV NSCLC as a second- or subsequent line therapy resulted in dramatic changes in patterns of failure, was well tolerated, and resulted in high PFS and OS, substantially greater than historical values for patients who only received systemic agents.


Lung Cancer | 2012

A multicenter phase II study of cisplatin, pemetrexed, and bevacizumab in patients with advanced malignant mesothelioma.

Jonathan E. Dowell; Frank R. Dunphy; Robert N. Taub; David E. Gerber; Jingsheng Yan; Yang Xie; Hedy L. Kindler

INTRODUCTION Malignant mesothelioma (MM) cells express the vascular endothelial growth factor (VEGF) receptor, and VEGF protein expression is detected in a majority of human mesothelioma biopsy specimens. Bevacizumab is a recombinant humanized monoclonal antibody that blocks the binding of VEGF to its receptor. We evaluated the addition of bevacizumab to cisplatin and pemetrexed as first-line treatment in patients with advanced, unresectable MM. METHODS Previously untreated MM patients with advanced, unresectable disease received cisplatin (75 mg/m(2)), pemetrexed (500 mg/m(2)), and bevacizumab (15 mg/kg) intravenously every 21 days for a maximum of 6 cycles. Patients with responsive or stable disease received bevacizumab (15 mg/kg) intravenously every 21 days until progression or intolerance. The primary endpoint was progression-free survival rate at 6 months. RESULTS 53 patients were enrolled at 4 centers; 52 were evaluable for this analysis. The progression-free survival rate at 6 months was 56% and the median progression-free survival was 6.9 months (95% confidence interval [CI], 5.3-7.8 months). The partial response rate was 40% and 35% of patients had stable disease. Median overall survival was 14.8 months (95% CI; 10.0-17.0 months). Grade 3/4 toxicities included neutropenia in 11%, hypertension in 6%, and venous thromboembolism in 13% of patients. CONCLUSION This trial evaluating the addition of bevacizumab to cisplatin and pemetrexed in patients with previously untreated, advanced MM failed to meet the primary endpoint of a 33% improvement in the progression-free survival rate at 6 months compared with historical controls treated with cisplatin and pemetrexed alone.


Drugs | 2012

Vemurafenib: Targeted inhibition of mutated BRAF for treatment of advanced melanoma and its potential in other malignancies

Anant Sharma; S. R. Shah; Henrik Illum; Jonathan E. Dowell

Vemurafenib is the first molecularly targeted therapy to be licensed in the US and Europe for treatment of advanced melanoma. Its mechanism of action involves selective inhibition of the mutated BRAF V600E kinase that leads to reduced signalling through the aberrant mitogen-activated protein kinase (MAPK) pathway. Its efficacy is restricted to melanomas carrying the BRAF V600E mutation, which is seen in approximately 50% of all melanomas. In a randomized phase III trial, it was superior to dacarbazine in first-line treatment of advanced melanoma, with an overall response rate (ORR) of 48% (95% CI 42, 45), an estimated 6-month progression-free survival (PFS) of 5.3 versus 1.6 months (hazard ratio [HR] 0.26; 95% CI 0.20, 0.33; p < 0.001) and a statistically superior 12-month overall survival (OS) rate of 55% versus 43% (HR 0.62 [95% CI 0.49, 0.77]). Vemurafenib is generally well tolerated, but its use can be associated with development of cutaneous neoplasms such as squamous cell carcinoma (SCC) and keratoacanthoma (KA). These lesions can be excised safely without the need for withholding the drug or reducing its dose. Mechanisms of resistance to vemurafenib do not involve development of secondary mutations in the BRAF kinase domain, but may be related to BRAF V600E over-amplification, bypassing mechanisms via upregulation and overexpression of other components in the MAPK signalling cascade or activation of alternative pathways with potential to enhance cell growth, proliferation and survival. Clinical trials to test the efficacy of vemurafenib in combination with immunomodulatory agents, such as ipilimumab, and MAPK kinase (MEK) inhibitors, such as GDC-0973, in the treatment of advanced melanoma are currently underway. Also under investigation is the use of vemurafenib in other solid tumours with BRAF mutations, such as papillary thyroid cancer.


Annals of Pharmacotherapy | 2006

Evaluation of Clinical Pharmacy Services in a Hematology/Oncology Outpatient Setting

Sachin R. Shah; Jonathan E. Dowell; Shane Greene

Background: The Veterans Affairs North Texas Health Care System in Dallas, TX, provides a unique opportunity for clinical pharmacists to work as providers. Even though clinical pharmacists are actively involved in patient care, many of their efforts remain undocumented, resulting in an underestimation of the importance of their services and missed opportunities for improvements and new directions. Objective: To document and evaluate the services of a hematology/oncology clinical pharmacy in the outpatient setting. Methods: Pendragon Forms 3.2 software was used to design the documentation template. The template was designed to collect diagnoses, supportive care issues, drug-specific interventions, and prescriptions written. This template was uploaded to the personal digital assistant (PDA) for documentation. Patient-specific information was documented in a password-protected PDA. Data collected from November 1, 2002, to October 31, 2003, were retrospectively analyzed. Results: Clinical pharmacists were involved in 423 patient visits for chemotherapy follow-up or disease management. Cancer diagnoses included colorectal (n = 99), multiple myeloma (59), non–small cell lung (56), chronic lymphocytic leukemia (44), myelodysplastic syndromes (22), and chronic myelogenous leukemia (19). During the 423 patient visits, 342 supportive care issues were addressed including anemia (34%), pain management (22%), constipation/diarrhea (15%), and nausea/vomiting (8%). Major drug-specific interventions included drug addition (41%), discontinuation (23%), and adjustment (21%). Four hundred forty-five prescriptions were filled, of which 181 were new and 150 were refilled. Conclusions: This is the first study, as of July 25, 2006, to document considerable contribution of an outpatient clinical pharmacist in direct cancer patient care. Although the disease management and supportive care issues addressed here may differ based on institution and patient population, the results of our study show that clinical pharmacists have ever-growing roles in the management of these patients.


Journal of Thoracic Oncology | 2010

Looking beyond surveillance, epidemiology, and end results: patterns of chemotherapy administration for advanced non-small cell lung cancer in a contemporary, diverse population.

Drew W. Rasco; Jingsheng Yan; Yang Xie; Jonathan E. Dowell; David E. Gerber

Introduction: Chemotherapy prolongs survival without substantially impairing quality of life for medically fit patients with advanced non-small cell lung cancer (NSCLC), but population-based studies have shown that only 20 to 30% of these patients receive chemotherapy. These earlier studies have relied on Medicare-linked Surveillance, Epidemiology, and End Results (SEER) data, thus excluding the 30 to 35% of lung cancer patients younger than 65 years. Therefore, we determined the use of chemotherapy in a contemporary, diverse NSCLC population encompassing all patient ages. Methods: We performed a retrospective analysis of patients diagnosed with stage IV NSCLC from 2000 to 2007 at the University of Texas Southwestern Medical Center. Demographic, treatment, and outcome data were obtained from hospital tumor registries. The association between these variables was assessed using univariate analysis and multivariate logistic regression. Results: In all, 718 patients met criteria for analysis. Mean age was 60 years, 58% were men, and 45% were white. Three hundred fifty-three patients (49%) received chemotherapy. In univariate analysis, receipt of chemotherapy was associated with age (53% of patients younger than 65 years versus 41% of patients aged 65 years and older; p = 0.003) and insurance type (p < 0.001). In a multivariate model, age and insurance type remained associated with receipt of chemotherapy. For individuals receiving chemotherapy, median survival was 9.2 months, compared with 2.3 months for untreated patients (p < 0.001). Conclusions: In a contemporary population representing the full age range of patients with advanced NSCLC, chemotherapy was administered to approximately half of all patients—more than twice the rate reported in some earlier studies. Patient age and insurance type are associated with receipt of chemotherapy.


Journal of Thoracic Oncology | 2011

Predictors and impact of second-line chemotherapy for advanced non-small cell lung cancer in the United States: real-world considerations for maintenance therapy.

David E. Gerber; Drew W. Rasco; Phat Le; Jingsheng Yan; Jonathan E. Dowell; Yang Xie

Introduction: Recent clinical trials incorporating maintenance chemotherapy into the initial treatment of advanced non-small cell lung cancer (NSCLC) have highlighted the benefits of exposing patients to second-line therapies. We, therefore, determined the predictors and impact of second-line chemotherapy administration in a contemporary, diverse NSCLC population. Methods: We performed a retrospective analysis of consecutive patients diagnosed with stage IV NSCLC from 2000 to 2007 at clinical facilities associated with the University of Texas Southwestern Medical Center. Demographic, disease, treatment, and outcome data were obtained from hospital tumor registries. The association between these variables was assessed using univariate analysis and multivariate logistic regression. Results: A total of 406 patients in this cohort received first-line chemotherapy and were included in the analysis. Mean age was 59 years, 28% were women, and 59% were white. Among these patients, 197 (49%) received second-line chemotherapy. Among those patients who had not progressed after four to six cycles of first-line chemotherapy, 67% received second-line chemotherapy. Receipt of second-line chemotherapy was significantly associated with patient insurance type (p = 0.007), number of cycles of first-line chemotherapy (p < 0.001), and receipt of prechemotherapy palliative radiation therapy (p = 0.005) but was not associated with patient age, gender, race, histology, or year of diagnosis. In a multivariate model, second-line chemotherapy administration remained associated with insurance type (p = 0.003), number of cycles of first-line chemotherapy (p < 0.001), and receipt of prechemotherapy palliative radiation therapy (p = 0.008). The number of cycles of first-line chemotherapy and administration of second-line chemotherapy were associated with overall survival in both univariate and multivariate analyses. Conclusions: In this unselected, contemporary, and diverse cohort of patients with advanced NSCLC, 67% of individuals whose disease had not progressed after four to six cycles of first-line chemotherapy eventually received second-line chemotherapy. Markers of socioeconomic status, symptom burden, and response to and tolerance of first-line chemotherapy were associated with receipt of second-line chemotherapy. These factors may assist in the selection of patients most likely to benefit from maintenance chemotherapy.


The American Journal of the Medical Sciences | 2010

Small cell lung cancer: are we making progress?

Jonathan E. Dowell; Biff F. Palmer

Although the incidence of small cell lung cancer (SCLC) has declined during the past 30 years, it remains a significant cause of cancer mortality in the United States and across the world. With appropriate treatment, about 20% of patients who present with limited stage SCLC can be cured of their disease. Unfortunately, the outcome for the remainder of patients is extremely poor. The only significant advance in extensive stage SCLC in the past 2 decades is the recent discovery that prophylactic cranial irradiation improves survival in those patients whose disease has responded to initial chemotherapy. Numerous attempts to enhance the antitumor effects of traditional chemotherapy for SCLC have not been successful. As the understanding of the biology of SCLC increased, a number of rational molecular targets for therapy have been identified. Although initial attempts at “targeted therapy” in SCLC have been unsuccessful, several newly identified targets hold promise and give hope that significant improvements in therapy for this challenging disease are not far away.


Clinical Cancer Research | 2007

A comparison of the pharmacokinetics and pharmacodynamics of docetaxel between African-American and Caucasian cancer patients: CALGB 9871.

Lionel D. Lewis; Antonius A. Miller; Gary L. Rosner; Jonathan E. Dowell; Manuel Valdivieso; Mary V. Relling; Merrill J. Egorin; Robert R. Bies; Donna Hollis; Ellis G. Levine; Gregory A. Otterson; Frederick Millard; Mark J. Ratain

Purpose: Increased clearance of drugs, such as oral cyclosporine, that are CYP3A and/or ABCB1 (P-gp/MDR1) substrates was reported in African-American compared with Caucasian patients. We hypothesized that the pharmacokinetics and pharmacodynamics of docetaxel, an i.v. administered cytotoxic and substrate for CYP3A4, CYP3A5, and ABCB1, would differ between African-American and Caucasian patients. Experimental Design: We investigated population pharmacokinetics and pharmacodynamics and the pharmacogenetics of CYP3A4, CYP3A5, and ABCB1 in African-American and Caucasian cancer patients who received docetaxel 75 or 100 mg/m2 as a 1-h i.v. infusion. Plasma docetaxel concentrations were measured by high-performance liquid chromatography. Clinical toxicity and absolute neutrophil count (ANC) were monitored on days 8, 15, and 22 postadministration of docetaxel. Using a limited sampling strategy and nonlinear mixed-effects modeling, each patients docetaxel clearance was estimated. Genotyping for known polymorphisms in CYP3A4, CYP3A5, and ABCB1 was done. Results: We enrolled 109 patients: 40 African-Americans (26 males; 14 females), with a median age of 61 years (range, 29-73), and 69 Caucasians (43 males; 26 females), with a median age of 63 years (range, 38-81). There was no difference in the geometric mean docetaxel clearance between African-American patients [40.3 L/h; 95% confidence interval (95% CI), 19.3-84.1] and Caucasian patients (41.8 L/h; 95% CI, 22.0-79.7; P = 0.6). We observed no difference between African-American and Caucasian patients in the percentage decrease in ANC nor were docetaxel pharmacokinetic parameters related to the genotypes studied. Conclusions: Docetaxel clearance and its associated myelosuppression were similar in African-American and Caucasian cancer patients.


Journal of Oncology Practice | 2013

Upper Extremity Venous Thrombosis in Patients With Cancer With Peripherally Inserted Central Venous Catheters: A Retrospective Analysis of Risk Factors

Daniel H. Ahn; Henrik Illum; David H. Wang; Anant Sharma; Jonathan E. Dowell

PURPOSE Peripherally inserted central catheters (PICCs) are often used in place of mediport catheters because of cost and lack of operating room time and to prevent delays in therapy. One common complication associated with their use is upper extremity venous thrombosis (UEVT). The purpose of this study was to ascertain risk factors associated with an increased risk of PICC-associated UEVT in patients with cancer. METHODS Retrospective analysis identified 237 patients with cancer who received PICCs at the Dallas Veterans Affairs Medical Center from 2006 to 2009. We analyzed many risk factors, including PICC infection (PI), use of erythropoiesis-stimulating agents (ESAs), antiplatelet agents (APAs), treatment dose anticoagulation (TDA), and bevacizumab. RESULTS Of 237 patients, 36 (15%) were found to have UEVT. Stepwise logistic regression analysis showed risk factors positively associated with UEVT were use of ESAs (odds ratio [OR], 10.66; 95% CI, 2.25 to 50.49), hospitalization (OR, 2.38; 95% CI, 1.05 to 5.39), PI (OR, 2.46; 95% CI, 1.03 to 5.86), and TDA (OR, 8.34; 95% CI, 2.98 to 23.33), whereas patients receiving APAs had a lower risk of UEVT (OR, 0.25; 95% CI, 0.07 to 0.92). CONCLUSION Specific factors significantly increase the risk of UEVT in patients with cancer with PICCs, whereas use of APAs seems to have a protective effect against UEVT. These results may aid in the development of a predictive model for identifying patients at high risk of UEVT who may benefit from APAs, as well as in determining preventive strategies for reducing the risk of PICC-associated UEVT.


Lung Cancer | 2015

A phase 1 safety study of veliparib combined with cisplatin and etoposide in extensive stage small cell lung cancer: A trial of the ECOG-ACRIN Cancer Research Group (E2511)

Taofeek K. Owonikoko; Suzanne E. Dahlberg; Saad A. Khan; David E. Gerber; Jonathan E. Dowell; Rebecca A. Moss; Chandra P. Belani; Christine L. Hann; Charu Aggarwal; Suresh S. Ramalingam

OBJECTIVES Veliparib (V) potentiated therapeutic efficacy of cisplatin (C) and etoposide (E) in preclinical models of SCLC. We conducted this phase 1 study to establish the safety of the combination in human subjects. MATERIALS AND METHODS The study employed the 3+3 dose escalation design to establish the safety and recommended phase 2 dose (RP2D) of V when combined with fixed doses of C (75 mg/m(2) on day 1) and E (100mg/m(2) on days 1-3) in a 21-day cycle. The starting dose of V was 60 mg (bid days 1-7) with plan to escalate to 100mg (days 1-7) or de-escalate to 40 mg (days 1-7) depending on the dose limiting toxicity (DLT) experience during cycle 1. Patients with treatment-naïve, extensive stage SCLC were included. RESULTS The study enrolled 9 patients: M/F (4/5); median age (60); White/African American (8/1). V was tolerated at the 60 mg (DLT in 0 of 3 patients) and 100mg dose (DLT in 1 of 6 patients; grade 5 cardiac failure). Veliparib at 100mg in combination with standard doses of C and E was established as the RP2D. Grades 3-5 adverse events irrespective of attribution during cycle 1 included: dehydration (1), diarrhea (1), fatigue (1), febrile neutropenia (1), heart failure (1), leukopenia (6), lymphopenia (1), nausea (2), neutropenia (8), respiratory failure (1), and thrombocytopenia (2). Investigator-assessed efficacy outcome in 7 evaluable patients were stable disease in 2/7 (28.6%), partial response in 4/7 (57.1%), and complete response in 1/7 (14.3%) patients. CONCLUSIONS This study demonstrated the safety of combining veliparib with cisplatin and etoposide in previously untreated SCLC patients.

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David E. Gerber

University of Texas Southwestern Medical Center

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Yang Xie

University of Texas Southwestern Medical Center

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Jingsheng Yan

University of Texas Southwestern Medical Center

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Hak Choy

University of Texas Southwestern Medical Center

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John D. Minna

University of Texas Southwestern Medical Center

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Drew W. Rasco

University of Texas Southwestern Medical Center

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Joan H. Schiller

University of Texas Southwestern Medical Center

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Puneeth Iyengar

University of Texas Southwestern Medical Center

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Robert D. Timmerman

University of Texas Southwestern Medical Center

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Zabi Wardak

University of Texas Southwestern Medical Center

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