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Biomedical subjects

Christopher W Ryan

Publications and source records attributed to Christopher W Ryan.

11 recordsLinked to original sources
PubMed2004

Dose-ranging study of the safety and pharmacokinetics of atrasentan in patients with refractory malignancies.

PURPOSE: Atrasentan is an orally bioavailable selective antagonist of the endothelin receptor ET(A). Due to the potential activity of this agent against prostate cancer, the majority of subjects enrolled in prior studies had been male. This Phase I study sought to determine the toxicity and pharmacokinetics of daily atrasentan in a population of both female and male subjects with advanced malignancies. EXPERIMENTAL DESIGN: Patients with refractory malignancies received atrasentan once daily at doses ranging from 5 mg to 75 mg. At least 3 subjects were treated at each dose level before enrollment began at the next higher dose level. Enrollment for specific dose levels was expanded if any subject experienced serious drug-related toxicity. Plasma concentration profiles for atrasentan were determined after dosing on days 1 and 28. RESULTS: Thirty-five patients received atrasentan at doses from 5 mg to 75 mg. The most frequent drug-related adverse events were headache (60%), rhinitis (49%), and peripheral edema (31%). These toxicities were mild to moderate in severity and reversible on cessation of treatment. Dose escalation was stopped at the 75-mg dose level due to the occurrence of three severe adverse events (2 hyponatremia and 1 hypotension). Atrasentan was rapidly absorbed after oral administration; mean time to maximum observed concentration ranged from 0.3 to 1.7 h. Terminal elimination half-life averaged 26 h. No significant difference between sexes was found in any atrasentan pharmacokinetic parameter tested, including maximum observed plasma concentration, time to maximum observed concentration, minimum observed plasma concentration, area under the plasma concentration-time curve, and elimination rate constant. CONCLUSIONS: Atrasentan is well tolerated in both female and male cancer patients at doses of up to 60 mg/day with dose-limiting toxicity observed at 75 mg/day. The most frequently observed toxicities were headache, rhinitis, and edema. There was no statistically significant difference in atrasentan pharmacokinetics between sexes.

Administration, Oral↗
PubMed2004

A randomized Phase II trial of the antiangiogenic agent SU5416 in hormone-refractory prostate cancer.

PURPOSE: To assess the activity of the antiangiogenic agent and VEGFR2 inhibitor SU5416 in hormone-refractory prostate cancer. PATIENTS AND METHODS: Thirty-six chemotherapy naïve patients were randomized to treatment with SU5416 (145 mg/m(2)) and dexamethasone premedication or dexamethasone alone. Patients in the control arm could cross over to experimental therapy after progression. Prostate-specific antigen (PSA) was measured every 2 weeks, and radiological evaluation was performed every 8 weeks. In vitro assessment of SU5416 on PSA secretion was assessed in the LNCaP cell line. Baseline serum basic fibroblast growth factor and plasma vascular endothelial growth factor (VEGF) were explored as prognostic factors. RESULTS: VEGF receptor-2 expression is detectable in prostate cancer cell lines, and SU5416 inhibited in vitro PSA secretion. No effect of SU5416 on PSA secretion or time to progression is detectable in patients. VEGF and basic fibroblast growth factor were not prognostic. Headache and fatigue were the most common SU5416 toxicities, but hyperglycemia, hyponatremia, lymphopenia, infection, and adrenal suppression, all attributable to steroids and the required central line, were common. CONCLUSION: No disease modifying effects of SU5416 were detectable in this small study. Modest toxicity, an inconvenient administration schedule, and availability of other VEGFR-targeted agents support the decision to halt further evaluation of SU5416 in prostate cancer.

Aged↗
PubMed2004

Phase II trial of PS-341 in patients with renal cell cancer: a University of Chicago phase II consortium study.

PURPOSE: Determine response rate, time to disease progression, and toxicity of the proteasome inhibitor PS-341 in patients with stage IV renal cell cancer. PATIENTS AND METHODS: PS-341 1.5 mg/m(2) was administered intravenously twice weekly for 2 weeks every 21 days. Dose escalation to 1.7 mg/m(2) ensued in the absence of grade 3 to 4 toxicities. Re-evaluation took place after three cycles. To assess proteasome inhibition, patients were randomly assigned to tumor core biopsy either before the first dose or after the third cycle of PS-341. Additionally, whole blood was collected at the same time intervals. RESULTS: Twenty-three patients were enrolled; 21 were assessable for response. Two patients were never treated (one patient refused treatment and one had insufficient tumor for biopsy). Eighteen patients completed at least three cycles of therapy; three patients experienced disease progression after two cycles. Grade 4 toxicities were arthralgia, diarrhea, and vomiting. Grade 3 toxicities included thrombocytopenia with one hemorrhage, anemia, febrile neutropenia, gastrointestinal toxicity, pain, fatigue, neuropathy (one sensory, one mixed sensorimotor), and electrolyte disturbances. Grade 1 to 2 neuropathy occurred in seven patients. One case of thrombosis and one case of pleural effusion occurred. Only one objective response was seen. Proteasome activity was measured by specific chymotryptic activity (SpA) and chymotryptic/tryptic activity (ChT:T). After PS-341, there was a decrease in mean whole blood SpA and ChT:T (P =.07 and.11, respectively). CONCLUSION: Evidence is lacking for clinically significant activity of PS-341 in metastatic renal cell cancer. Insufficient biopsy and whole blood sample numbers preclude conclusions regarding proteasome inhibition within tumor. Further evaluation in this disease setting is not recommended.

Adult↗
PubMed2003

Surgical treatment of gastrointestinal stromal tumors in the imatinib (STI-571) era.

BACKGROUND: Gastrointestinal stromal tumors (GIST) are rare mesenchymal tumors that are characterized by constitutive overexpression of the tyrosine kinase receptor KIT (CD117). Imatinib mesylate is a selective inhibitor of tyrosine kinase-mediated activity. This study reports a single-institution experience of surgical resection and the use of imatinib in the treatment of GIST. METHODS: A retrospective review from 1995 to 2002 identified 57 patients (M:F, 29:28; median age, 61 years) with GIST who were treated at the University of Chicago. Twenty-eight patients underwent exploratory surgery with curative intent; 29 patients were referred for treatment of metastatic disease after surgery at outside institutions. Twenty-nine patients were treated with oral imatinib for either metastatic disease (n=26 patients) or in the adjuvant setting after complete resection (n=3 patients). RESULTS: Resections were performed in 53 patients, and metastatic disease was identified in 17 patients at the time of exploratory surgery. Immunohistochemical staining for CD117 was positive in 96% of patients. A size larger than 5 cm, a mitotic rate larger than 1/10 high-power field, and tumor necrosis predicted recurrence in patients after resection. The median follow-up period was 18 months (range, 4-81 months). Twenty-three patients (40%) are alive without disease; 22 patients (39%) are alive with disease; 7 patients died, and 5 patients are lost to follow-up. Among the 26 patients with metastatic disease who were treated with imatinib, 5 deaths have occurred, and disease stabilization or tumor regression was observed initially in 22 patients, with a median duration of response of 19 months. CONCLUSIONS: Complete surgical extirpation remains the only curative treatment of GIST. Imatinib-targeted therapy of metastatic disease yields encouraging clinical responses. The true efficacy of imatinib in this setting, as induction therapy or as an adjuvant treatment in patients with GIST, is unknown pending the completion of ongoing prospective trials.

Antineoplastic Agents↗
PubMed2003

Prognostic factors for survival with gemcitabine plus 5-fluorouracil based regimens for metastatic renal cancer.

PURPOSE: Combination gemcitabine and 5-fluorouracil (5-FU) may have activity in metastatic renal cell cancer. To identify patient subgroups most likely to benefit and compare survival to that in previously described patient series long-term survival as a function of known and suspected prognostic variables was determined. MATERIALS AND METHODS: The survival status of 153 patients with metastatic renal cell cancer treated on 1 phase I and 4 phase II trials of gemcitabine/5-FU based regimens was updated. Univariate and multivariate Cox proportional hazards models were constructed using multiple imputation for missing values. RESULTS: Performance status, prior nephrectomy, number of metastatic sites, decreased albumin and elevated alkaline phosphatase were highly prognostic for survival. Sarcomatoid differentiation and hypercalcemia had borderline prognostic significance. Using a previous described prognostic model that divided patients into 3 risk groups survival in those treated with gemcitabine/5-FU in this series was consistently better than survival in similar patients treated in the Motzer series. CONCLUSIONS: Previously described prognostic factors for survival in metastatic renal cancer were confirmed. There is no clearly identifiable group that is most likely to benefit from a gemcitabine/5-FU regimen but there is a continued suggestion that this regimen provides a modest improvement over historical chemotherapy approaches.

Antimetabolites, Antineoplastic↗
PubMed2003

Angiosarcoma masquerading as embryonal carcinoma in the metastasis from a mature testicular teratoma.

Sarcoma can arise within a germ cell tumor (GCT) from a malignant transformation of teratomatous elements or as late sequelae to radiation therapy. Angiosarcoma as a malignant component in testicular GCTs has rarely been reported and is often misdiagnosed as embryonal carcinoma. We report the case of a 23-year-old man with mature teratoma of the testis and retroperitoneal metastasis exhibiting components of mature teratoma intermingled with high-grade angiosarcoma. It is important to recognize the presence of a high-grade sarcomatous component within a GCT because of its aggressive clinical behavior and different response to therapy.

Adult↗
PubMed2002

A phase II trial of intravenous gemcitabine and 5-fluorouracil with subcutaneous interleukin-2 and interferon-alpha in patients with metastatic renal cell carcinoma.

BACKGROUND: The objective of this study was to determine the response rate and toxicity of gemcitabine and continuous-infusion 5-fluorouracil (5-FU) in combination with subcutaneous interleukin-2 (IL2) and interferon-alpha (IFNA) in patients with metastatic renal cell carcinoma. METHODS: Forty-one patients were treated with gemcitabine 600 mg/m2 on Days 1, 8, and 15 and continuous-infusion 5-FU on Days 1-21. The dose of 5-FU was 200 mg/m2 per day for the initial 8 patients but was reduced to 150 mg/m2 per day for all remaining patients due to toxicity. Starting on Day 15, IL2 and IFNA were administered for 4 weeks. IL2 was administered at a dose of 11 x 10(6) IU subcutaneously (s.c.) 4 days per week and IFNA was administered at a dose of 10.0 x 10(6) IU s.c. 2 days per week. RESULTS: Of 41 patients enrolled in the study, there was 1 complete response (CR), and there were 5 partial responses (PR), for an overall response rate of 14.6% (90% confidence interval [90%CI], 6.6-26.9%). The median time to disease progression was 6.6 months (90%CI, 3.9-7.5 months), and the median overall survival was 20.6 months (90%CI, 9.6-23.3 months). Toxicity was moderate to severe, with fatigue, fever, anorexia, or nausea experienced by 75-90% of patients. Mucositis and neutropenia, likely due to the gemcitabine and 5-FU, were experienced by a majority of patients. CONCLUSIONS: The addition of gemcitabine and 5-FU to subcutaneous IL2 and IFNA results in a similar response rate to what was observed in previous studies of IL2-based therapy. The toxicity of this four-drug combination is significant, and the regimen is not recommended for further development.

Adult↗
PubMed2002

A phase I study of suramin with once- or twice-monthly dosing in patients with advanced cancer.

PURPOSE: The optimal schedule of administration of suramin has not been well defined. The purpose of this study was to determine the maximum tolerated dose and toxicities of suramin when administered using a fixed dosing scheme on a once- or twice-monthly schedule. METHODS: A total of 40 patients were treated on this phase I dose-escalation study employing a once-monthly (day 1 of each 28-day cycle) and a twice-monthly (days 1 and 8 of each 28-day cycle) schedule. RESULTS: The most common dose-limiting events included fatigue, neuropathy, and anorexia. We identified the 1440 mg/m(2) dose level to be the maximal tolerated dose for both schedules, with 83% of patients developing dose-limiting toxicity (DLT) on the twice-monthly schedule, and 67% developing DLT on the monthly schedule. At the 1200 mg/m(2) dose level, only 25% developed DLT on the twice-monthly schedule and 33% developed DLT on the monthly schedule. Trough suramin levels gradually increased with higher dose levels but fell well below the putative toxic concentration of 350 microg/ml. CONCLUSION: Suramin can be safely administered using a monthly schedule without using plasma concentrations to guide dosing.

Adult↗