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Shamloo B.K.,Nevada Cancer Institute | Chhabra P.,University of Maryland, Baltimore | Freedman A.N.,U.S. National Institutes of Health | Potosky A.,Lombardi Comprehensive Cancer Center | And 2 more authors.
Drug Safety | Year: 2012

Background: Bevacizumab is the first in its class, vascular endothelial growth factor (VEGF) inhibitor that was initially approved by the US FDA in 2004 for the treatment of metastatic colon cancer and other solid tumors. Preapproval clinical trials, particularly for oncology drugs, are limited in their ability to detect certain adverse effects and, therefore, the FDA and pharmaceutical sponsors collect and monitor reports of adverse events (AEs) following approval. Objective: The purpose of this study was to screen the FDA's Adverse Event Reporting System (AERS) database for novel AEs that may be attributed to bevacizumab. Methods: The FDA AERS database was used to identify all AE reports for bevacizumab from February 2004 to September 2009. Disproportionality analysis was conducted for bevacizumab against all other drugs in the background by setting statistical significance at proportional reporting ratio (PRR) ≥2, observed case count ≥3 and chi-square ≥4. Subsequent clinical evaluation was performed to determine the clinical relevance of the findings and to group related events. Results: A total of 523 Preferred Terms (PTs) were disproportionally reported; following clinical review 63 (12%) were found to be both unlabelled and of clinical importance. These PTs were grouped into 15 clinical disorder groups. Among the clinical disorders, electrolyte abnormalities had the greatest number of reports (n = 426) followed by cardiovascular events (n = 421), gastrointestinal events (n = 345), nervous system disorders (n = 106) and pneumonitis (n = 96). On sensitivity analysis, a number of clinically important unlabelled disorders, such as necrotizing fasciitis, vessel wall disorders, arrhythmia and conduction disorder and autoimmune thrombocytopenia still met the statistical significance criteria. Conclusions: During the study period, out of 12 010 AE reports mentioning bevacizumab, it was listed as the suspect drug in 94.2% of the reports. Our disproportionality analysis identified many events that are already recognized as AEs of bevacizumab, but it also identified a number of clinically important unlabelled terms, which if confirmed in future studies would have potential implications for use of bevacizumab in clinical practice. © 2012 Springer International Publishing AG. All rights reserved. Source


Michaud K.,University of California at San Francisco | Solomon D.A.,Georgetown University | Oermann E.,Georgetown University | Kim J.-S.,Georgetown University | And 6 more authors.
Cancer Research | Year: 2010

Activation of cyclin-dependent kinases 4 and 6 (cdk4/6) occurs in the majority of glioblastoma multiforme (GBM) tumors, and represents a promising molecular target for the development of small molecule inhibitors. In the current study, we investigated the molecular determinants and in vivo response of diverse GBM cell lines and xenografts to PD-0332991, a cdk4/6-specific inhibitor. In vitro testing of PD-0332991 against a panel of GBM cell lines revealed a potent G1 cell cycle arrest and induction of senescence in each of 16 retinoblastoma protein (Rb)-proficient cell lines regardless of other genetic lesions, whereas 5 cell lines with homozygous inactivation of Rb were completely resistant to treatment. Short hairpin RNA depletion of Rb expression conferred resistance of GBM cells to PD-0332991, further demonstrating a requirement of Rb for sensitivity to cdk4/6 inhibition. PD-0332991 was found to efficiently cross the blood-brain barrier and proved highly effective in suppressing the growth of intracranial GBM xenograft tumors, including those that had recurred after initial therapy with temozolomide. Remarkably, no mice receiving PD-0332991 died as a result of disease progression while on therapy. Additionally, the combination of PD-0332991 and radiation therapy resulted in significantly increased survival benefit compared with either therapy alone. In total, our results support clinical trial evaluation of PD-0332991 against newly diagnosed as well as recurrent GBM, and indicate that Rb status is the primary determinant of potential benefit from this therapy. ©2010 AACR. Source


Smith K.L.,Washington Cancer Institute | Isaacs C.,Georgetown University | Isaacs C.,Lombardi Comprehensive Cancer Center
Cancer Journal | Year: 2011

BRCA mutation-associated breast cancer differs from sporadic breast cancer with regard to future cancer risks and sensitivity to systemic therapies. Now that rapid genetic testing for BRCA1 and BRCA2 mutations is available at the time of breast cancer diagnosis, BRCA mutation status can be considered when making treatment and prevention decisions for BRCA mutation carriers with breast cancer. This article reviews surgical options for management of affected BRCA mutation carriers with emphasis on the risks of ipsilateral recurrence and contralateral breast cancer. The roles of breast-conserving surgery, prophylactic mastectomy, and oophorectomy are reviewed. In addition, the sensitivity of BRCA mutation-associated breast cancer to endocrine therapy, platinum chemotherapy, and poly (ADP-ribose) polymerase inhibitors is reviewed. Copyright © 2011 by Lippincott Williams & Wilkins. Source


Potosky A.L.,Lombardi Comprehensive Cancer Center
Journal of the National Cancer Institute | Year: 2011

Myeloid colony-stimulating factors (CSFs) decrease the risk of febrile neutropenia (FN) from high-risk chemotherapy regimens administered to patients at 20% or greater risk of FN, but little is known about their use in clinical practice. We evaluated CSF use in a multiregional population-based cohort of lung and colorectal cancer patients (N = 1849). Only 17% (95% confidence interval [CI] = 8% to 26%) patients treated with high-risk chemotherapy regimens received CSFs, compared with 18% (95% CI = 16% to 20%) and 10% (95% CI = 8% to 12%) of patients treated with intermediate- (10%-20% risk of FN) and low-risk (<10% risk of FN) chemotherapy regimens, respectively. Using a generalized estimating equation model, we found that enrollment in a health maintenance organization (HMO) was strongly associated with a lower adjusted odds of discretionary CSF use, compared with non-HMO patients (odds ratio = 0.44, 95% CI = 0.32 to 0.60, P <. 001). All statistical tests were two-sided. Overall, 96% (95% CI = 93% to 98%) of CSFs were administered in scenarios where CSF therapy is not recommended by evidence-based guidelines. This finding suggests that policies to decrease CSF use in patients at lower or intermediate risk of FN may yield substantial cost savings without compromising patient outcomes. © 2011 The Author. Source


Etzioni R.,Fred Hutchinson Cancer Research Center | Gulati R.,Fred Hutchinson Cancer Research Center | Mallinger L.,Fred Hutchinson Cancer Research Center | Mandelblatt J.,Lombardi Comprehensive Cancer Center
Annals of Internal Medicine | Year: 2013

Knowledge of the likelihood that a screening-detected case of cancer has been overdiagnosed is vitally important to make treatment decisions and develop screening policy. An overdiagnosed case is an excess case detected by screening. Estimates of the frequency of overdiagnosis in breast and prostate cancer screening vary greatly across studies. This article identifies features of overdiagnosis studies that influence results and shows their effect by using published research. First, different ways to define and measure overdiagnosis are considered. Second, contextual features and how they affect overdiagnosis estimates are examined. Third, the effect of estimation approach is discussed. Many studies use excess incidence under screening as a proxy for overdiagnosis. Others use statistical models to make inferences about lead time or natural history and then derive the corresponding fraction of cases that are overdiagnosed. This article concludes with questions that readers of overdiagnosis studies can use to evaluate the validity and relevance of published estimates and recommends that authors of studies quantifying overdiagnosis provide information about these features. © 2013 American College of Physicians. Source

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