Elwyn Cabebe

All Publications

• Clinical trials of VEGF receptor tyrosine kinase inhibitors in pancreatic cancer EXPERT OPINION ON INVESTIGATIONAL DRUGS Cabebe, E., Fisher, G. A. 2007; 16 (4): 467-476

  Abstract

  Pancreatic cancer is the fourth leading cause of cancer-related deaths in Western countries and is among the deadliest diseases in humans. At present, gemcitabine is the standard chemotherapy for advanced pancreatic cancer, although (despite its use) prognosis continues to be dismal with a median survival of < 6 months. While targeting tumor vasculature has provided improved outcomes in colon, lung, breast and renal cell cancers, trials of angiogenesis inhibitors have lagged behind in pancreatic cancer. This review provides the rationale for exploring antiangiogenic therapies in the treatment of pancreatic cancer as well as summarizes present clinical development of VEGF receptor tyrosine kinase inhibitors and their application to pancreatic cancer.

  View details for DOI 10.1517/13543784.16.4.467

  View details for Web of Science ID 000245307500007

  View details for PubMedID 17371195

• Role of anti-angiogenesis agents in treating NSCLC: focus on bevacizumab and VEGFR tyrosine kinase inhibitors. Current treatment options in oncology Cabebe, E., Wakelee, H. 2007; 8 (1): 15-27

  Abstract

  OPINION STATEMENT: Successful inhibition of angiogenesis with the anti-vascular endothelial growth factor (VEGF) antibody bevacizumab has improved the efficacy seen with standard cytotoxic therapy in NSCLC. The addition of bevacizumab to first-line chemotherapy improved response rate and progression free survival and added 2 months to median overall survival for those patients with advanced stage NSCLC on the treatment arm of E4599. Bevacizumab is now a standard agent to add to frontline carboplatin and paclitaxel for patients with newly diagnosed NSCLC who meet the eligibility criteria from the landmark E4599 trial. Unfortunately about half of all patients are not eligible either because they have squamous histology, brain metastases, or are on anti-coagulation. Ongoing trials are further exploring the safety of bevacizumab in these patient populations, as well as in combination with other cytotoxic regimens. Exploration of other applications of bevacizumab in the second-line and adjuvant setting are ongoing as well. The largest class of drugs that block angiogenesis are the multi-targeted tyrosine kinase inhibitors (TKIs) that target the VEGF receptor (VEGFR). These drugs are still in development, and though two are now on the market for treating other malignancies, their role in NSCLC is under investigation. These agents have the advantages of hitting multiple targets, convenient oral administration, and potential for lower cost. Their lack of target specificity leads to unexpected toxicity, but also promising efficacy. For example, the overall objective response rate of 9.5% with single agent sunitinib compares similarly to that of pemetrexed or docetaxel in previously treated NSCLC patients, but toxicity, notably fatigue, lead to discontinuation in 38% of patients. Hypertension, hemorrhage and cavitation are common toxicities amongst this class of agents. Rash, fatigue, myalgia, and hand-foot syndrome are more specifically seen with TKIs. These compounds may also be synergistic or additive with traditional cytotoxic chemotherapy drugs and other novel compounds. In early trials sorafenib as a single agent has shown no clinical response in previously treated NSCLC patients, whereas clinical benefit in combination with erlotinib or chemotherapy has been seen in early studies. Vandetanib has demonstrated objective responses as a single agent and in combination with chemotherapy in previously treated NSCLC patients. A phase I trial of AZD2171 with carboplatin and paclitaxel in newly diagnosed advanced stage NSCLC also demonstrated promising results with 6 of 15 patients achieving partial responses. NSCLC specific trials are also underway, or in development for pazopanib, axitinib, AMG 706, XL647, enzastaurin, and other TKIs. Other anti-angiogenesis agents with different mechanisms of action include thalidomide and its derivatives, monoclonal antibodies to the VEGFRs, and VEGF Trap, a chimeric molecule which combines extracellular portions of VEGFR1 and VEGFR2 with the Fc portion of immunoglobulin G1 to form a molecule that binds and "traps" VEGF. Despite modest improvements, prognosis continues to be poor for patients with advanced NSCLC. Bevacizumab is a first step into the world of angiogenesis inhibitors for NSCLC and though it only offers a modest survival benefit in a limited patient population, it paves the way for the development of the next generation of anti-angiogenesis inhibitors. We can hope that further improvements in survival will follow.

  View details for PubMedID 17634832

• Sunitinib: A newly approved small-molecule inhibitor of angiogenesis DRUGS OF TODAY Cabebe, E., Wakelee, H. 2006; 42 (6): 387-398

  Abstract

  The advent of targeted therapies has allowed treatment to be directed at signaling pathways integral to tumor growth and survival. Sunitinib (SU11248, sunitinib malate; Pfizer Inc., New York, NY, USA) is a novel oral small-molecule multitargeted receptor tyrosine kinase inhibitor that has demonstrated direct antitumor activity and antiangiogenic action. It targets the vascular endothelial growth factor receptor (VEGFR), platelet derived growth factor receptor (PDGFR), stem-cell factor receptor and Fms-like tyrosine kinase receptor 3 receptor tyrosine-kinases. In January 2006, sunitinib malate was granted approval by the U.S. Food and Drug Administration for the treatment of gastrointestinal stromal tumor after disease progression on, or intolerance to, imatinib mesylate, as well as for the treatment of metastatic renal cell cancer. This review will discuss the development of sunitinib, particularly in acute myeloid leukemia, imatinib-resistant gastrointestinal stromal tumors and renal cell cancer. The review will also discuss ongoing trials with sunitinib in other malignancies such as neuroendocrine tumors and breast cancer, as well as its potential future development in combination therapy with other agents and in other malignancies.

  View details for DOI 10.1358/dot.2006.42.6.985633

  View details for PubMedID 16845442

• Intensity-modulated radiation therapy for the spine at the University of California, Irvine. Medical dosimetry Kuo, J. V., Cabebe, E., Al-Ghazi, M., Yakoob, I., Ramsinghani, N. S., Sanford, R. 2002; 27 (2): 137-145

  Abstract

  Radiation treatment of malignant diseases of the spine poses unique challenges to the radiation oncology treatment team. Intensity-modulated radiation therapy (IMRT) offers the capability of delivering high doses to targets near the spine while respecting spinal cord tolerance. At the University of California, Irvine, 8 patients received a total of 10 courses to the spine for a variety of primary and metastatic malignant conditions. This paper discusses anatomical considerations, spinal cord radiation myelopathy, and treatment planning issues as it relates to the treatment of spinal cord lesions. Between October 1997 and August 2001, a total of 8 patients received 10 courses of IMRT for primary or metastatic disease of the spine. Cancers treated included metastatic lung, renal, adrenocortical cancers, and primary sarcomas and giant cell tumor. Five cases had 6 courses given for re-irradiation of symptomatic disease and 3 cases had 4 courses of IMRT as primary management of their spinal lesions. Although 3 courses were given postoperatively, these were for grossly residual disease. For the re-irradiation patients, the mean follow-up interval was 4 months. The local control was estimated at 14%. Of the patients treated with primary intent, the mean follow-up was 9 months and the local control rate 75%. No patients developed spinal cord complications.

  View details for PubMedID 12074465