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Charles D Blanke

Publications and source records attributed to Charles D Blanke.

28 records · Page 2Linked to original sources
PubMed2004

Targeted therapies in the treatment of colorectal cancer: what managed care needs to know.

OBJECTIVE: This review is designed to explore the disease, its current treatment, the expanding field of antiangiogenic treatments, and the implications of these advances for the managed care patient. DATA SOURCES: This article is based, in part, on presentations given by the authors in a continuing education symposium presented during the Academy of Managed Care Pharmacy.s 16th Annual Meeting and Showcase, April 1, 2004, in San Francisco. CONCLUSIONS: Colorectal cancer (CRC) is the third most common cancer in the United States, and the second-leading non.gender-specific cause of cancer deaths. If the cancer is caught soon enough (before node involvement and metastasis occur), there is a strong chance of survival; however, only slightly more than one third of cases are detected that soon. Emerging treatments that target only the cancer cells are increasing the length of survival for those who are diagnosed at later stages of the disease.

Antibodies, Monoclonal↗
PubMed2003

Kinase mutations and imatinib response in patients with metastatic gastrointestinal stromal tumor.

PURPOSE: Most gastrointestinal stromal tumors (GISTs) express constitutively activated mutant isoforms of KIT or kinase platelet-derived growth factor receptor alpha (PDGFRA) that are potential therapeutic targets for imatinib mesylate. The relationship between mutations in these kinases and clinical response to imatinib was examined in a group of patients with advanced GIST. PATIENTS AND METHODS: GISTs from 127 patients enrolled onto a phase II clinical study of imatinib were examined for mutations of KIT or PDGFRA. Mutation types were correlated with clinical outcome. RESULTS: Activating mutations of KIT or PDGFRA were found in 112 (88.2%) and six (4.7%) GISTs, respectively. Most KIT mutations involved exon 9 (n = 23) or exon 11 (n = 85). All KIT mutant isoforms, but only a subset of PDGFRA mutant isoforms, were sensitive to imatinib, in vitro. In patients with GISTs harboring exon 11 KIT mutations, the partial response rate (PR) was 83.5%, whereas patients with tumors containing an exon 9 KIT mutation or no detectable mutation of KIT or PDGFRA had PR rates of 47.8% (P =.0006) and 0.0% (P <.0001), respectively. Patients whose tumors contained exon 11 KIT mutations had a longer event-free and overall survival than those whose tumors expressed either exon 9 KIT mutations or had no detectable kinase mutation. CONCLUSION: Activating mutations of KIT or PDGFRA are found in the vast majority of GISTs, and the mutational status of these oncoproteins is predictive of clinical response to imatinib. PDGFRA mutations can explain response and sensitivity to imatinib in some GISTs lacking KIT mutations.

Animals↗
PubMed2003

Irinotecan and paclitaxel in metastatic adenocarcinoma of the esophagus and gastric cardia.

Both irinotecan (CPT-11, Camptosar) and paclitaxel have been shown to have single-agent activity in adenocarcinomas of the esophagus and gastric cardia. A phase I trial of the combination at UCLA established the dose as irinotecan at 225 mg/m2 and paclitaxel at 100 mg/m2 every 3 weeks. Preliminary data from a phase II trial of this regimen in adenocarcinomas of the gastroesophageal junction show good tolerability and promising activity (response rate of 27%), even in previously treated patients.

Adenocarcinoma↗
PubMed2002

Efficacy and safety of imatinib mesylate in advanced gastrointestinal stromal tumors.

BACKGROUND: Constitutive activation of KIT receptor tyrosine kinase is critical in the pathogenesis of gastrointestinal stromal tumors. Imatinib mesylate, a selective tyrosine kinase inhibitor, has been shown in preclinical models and preliminary clinical studies to have activity against such tumors. METHODS: We conducted an open-label, randomized, multicenter trial to evaluate the activity of imatinib in patients with advanced gastrointestinal stromal tumor. We assessed antitumor response and the safety and tolerability of the drug. Pharmacokinetics were assessed in a subgroup of patients. RESULTS: A total of 147 patients were randomly assigned to receive 400 mg or 600 mg of imatinib daily. Overall, 79 patients (53.7 percent) had a partial response, 41 patients (27.9 percent) had stable disease, and for technical reasons, response could not be evaluated in 7 patients (4.8 percent). No patient had a complete response to the treatment. The median duration of response had not been reached after a median follow-up of 24 weeks after the onset of response. Early resistance to imatinib was noted in 20 patients (13.6 percent). Therapy was well tolerated, although mild-to-moderate edema, diarrhea, and fatigue were common. Gastrointestinal or intraabdominal hemorrhage occurred in approximately 5 percent of patients. There were no significant differences in toxic effects or response between the two doses. Imatinib was well absorbed, with pharmacokinetics similar to those reported in patients with chronic myeloid leukemia. CONCLUSIONS: Imatinib induced a sustained objective response in more than half of patients with an advanced unresectable or metastatic gastrointestinal stromal tumor. Inhibition of the KIT signal-transduction pathway is a promising treatment for advanced gastrointestinal stromal tumors, which resist conventional chemotherapy.

Adolescent↗
PubMed2002

Inhibition of KIT tyrosine kinase activity: a novel molecular approach to the treatment of KIT-positive malignancies.

PURPOSE: Activation of the KIT tyrosine kinase by somatic mutation has been documented in a number of human malignancies, including gastrointestinal stromal tumor (GIST), seminoma, acute myelogenous leukemia (AML), and mastocytosis. In addition, paracrine or autocrine activation of this kinase has been postulated in numerous other malignancies, including small-cell lung cancer and ovarian cancer. In this review, we discuss the rationale for and development of KIT tyrosine kinase inhibitors for the treatment of human malignancies. MATERIALS AND METHODS: Studies were identified through a MEDLINE search, review of bibliographies of relevant articles, and review of abstracts from national meetings. RESULTS: Four tyrosine kinase inhibitors that have activity against KIT are currently being used in clinical trials, and one, STI571, has recently been approved by the United States Food and Drug Administration for treating patients with chronic myelogenous leukemia. The role of KIT inhibitors in treating KIT-positive malignancies is reviewed. CONCLUSION: Targeted therapy to inhibit the kinase activity of KIT is a rational approach to the treatment of KIT-positive malignancies. Two key factors are the potency of a given inhibitor and the relative contribution of KIT activation to the growth of the tumor. Given our current understanding of KIT activity in human malignancy, the best candidate diseases for treatment with KIT inhibitors are GIST, mastocytosis, seminoma and possibly some cases of AML. Additionally, KIT inhibitors may play an adjunctive role in diseases such as small-cell lung cancer, in which KIT activation is secondary to ligand binding rather than an acquired mutation.

Angiogenesis Inhibitors↗
PubMed2002

Celecoxib with chemotherapy in colorectal cancer.

Cyclooxygenase-2 (COX-2) is the enzyme that normally synthesizes prostaglandins during an inflammatory response. Many primary and metastatic cancers express COX-2, and its presence is correlated with tumor angiogenesis, more invasive tumor phenotype, resistance to apoptosis, and systemic immunosuppression. The expression of COX-2 is associated with a worse prognosis. Inhibition of prostaglandin synthesis may be beneficial in human malignancy. Regular consumption of nonsteroidal anti-inflammatory drugs (NSAIDs) decreases the incidence of, and mortality rate resulting from, a number of types of gastrointestinal cancers. Premalignant colonic lesions regress following the administration of nonspecific COX inhibitors, such as sulindac (Clinoril). Advanced solid tumor patients treated with indomethacin (Indocin) survive twice as long as do such patients who receive supportive care alone. The U.S. Food and Drug Administration has approved specific COX-2 inhibitors for the treatment of arthritis, pain, and familial adenomatous polyposis. Preclinical studies show that these drugs block angiogenesis, suppress solid tumor metastases, and slow the growth of implanted gastrointestinal cancer cell lines. The COX-2 inhibitors have safely and effectively been combined with chemotherapeutic agents in experimental studies. Ongoing clinical trials are currently assessing the potential therapeutic role of COX-2 inhibitors in both prevention and treatment of a diverse range of human cancers.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2002

Cancers of the gallbladder and biliary ducts.

Neoplasms of the biliary tract tree are uncommon and have a poor overall prognosis. Although numerous risk factors have been identified, little is known about the pathogenesis of these tumors, and no effective screening technique is available for early detection. Surgery remains the principal treatment modality and the only potential cure, with laparoscopy playing an increasingly important role in determining the resectability of these tumors. The role of postoperative adjuvant chemotherapy and radiation remains controversial. The efficacy of chemotherapy for advanced disease is relatively limited, with response rates of less than 10% for single-agent fluorouracil. Of the newer agents, gemcitabine (Gemzar) holds the most promise in the treatment of these difficult malignancies.

Bile Duct Neoplasms↗
PubMedDate not supplied

Outcome following surgical therapy for gastrointestinal stromal tumors.

We have pursued an approach of complete resection for patients with gastrointestinal stromal tumors (GISTs), including multivisceral resection, for patients with disease involving adjacent organs. We have also extended the limits of resection to include patients with metastatic disease who were treated with imatinib mesylate. The aim of this study is to report the outcomes and prognostic factors associated with this clinical approach. Study subjects were identified using the pathology database at our institution; for inclusion in the study group, patients must have undergone surgical resection for a KIT-positive gastrointestinal stromal tumor between January 1992 and March 2004. We calculated survival by using the Kaplan-Meier method. Univariate and multivariate analysis was performed using log-rank analysis and the Cox proportional hazards model. Thirty-four patients met the study criteria. Fifty-nine percent of patients had GISTs of gastric origin, 20.6% had duodenal GISTs, and the remainder was comprised of a variety of other sites. Twenty-two (64.7%) patients underwent single-organ resection, and 12 patients (35.3%) underwent multivisceral resection. Estimated actuarial survival at 5 years was 65.2%. Seven patients (five patients with metastases, one patient with locally advanced disease, and one patient with organ-confined disease) received imatinib mesylate. Independent predictors of poor survival included incomplete resection, metastatic disease at presentation, and high mitotic index. Mitotic index and the presence of metastases remain the primary predictors of postoperative survival. Complete surgical resection, even if multivisceral resection is required, is associated with improved survival.

Biomarkers, Tumor↗