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Biomedical subjects

J Dancey

Publications and source records attributed to J Dancey.

At least 19 recordsLinked to original sources
PubMed2006

A phase II clinical and pharmacodynamic study of temsirolimus in advanced neuroendocrine carcinomas.

Standard cytotoxic treatments for neuroendocrine tumours have been associated with limited activity and remarkable toxicity. A phase II study was designed to evaluate the efficacy, safety and pharmacodynamics of temsirolimus in patients with advanced neuroendocrine carcinoma (NEC). Thirty-seven patients with advanced progressive NEC received intravenous weekly doses of 25 mg of temsirolimus. Patients were evaluated for tumour response, time to progression (TTP), overall survival (OS) and adverse events (AE). Twenty-two archival specimens, as well as 13 paired tumour biopsies obtained pretreatment and after 2 weeks of temsirolimus were assessed for potential predictive and correlative markers. The intent-to-treat response rate was 5.6% (95% CI 0.6-18.7%), median TTP 6 months and 1-year OS rate 71.5%. The most frequent drug-related AE of all grades as percentage of patients were: fatigue (78%), hyperglycaemia (69%) and rash/desquamation (64%). Temsirolimus effectively inhibited the phosphorylation of S6 (P=0.02). Higher baseline levels of pmTOR (phosphorylated mammalian target of rapamycin) (P=0.01) predicted for a better response. Increases in pAKT (P=0.041) and decreases in pmTOR (P=0.048) after treatment were associated with an increased TTP. Temsirolimus appears to have little activity and does not warrant further single-agent evaluation in advanced NEC. Pharmacodynamic analysis revealed effective mTOR pathway downregulation.

Adult↗
PubMed2006

Phase II study of erlotinib (OSI-774) in patients with metastatic colorectal cancer.

Erlotinib (Tarceva, OSI-774), a potent epidermal growth factor receptor tyrosine kinase inhibitor (EGFR), was evaluated in a phase II study to assess its activity in patients with metastatic colorectal cancer. In all, 38 patients with metastatic colorectal cancer were treated with erlotinib at a continuous daily oral dose of 150 mg. Radiological evaluation was carried out every 8 weeks and tumour biopsies were performed before treatment and on day 8. Of 31 evaluable patients, 19 (61%) had progressive disease and 12 (39%) had stable disease (s.d.). The median time to progression for those patients having s.d. was 123 days (range 108-329 days). The most common adverse events were rash in 34 patients and diarrhoea in 23 patients. Correlative studies were conducted to investigate the effect of erlotinib on downstream signalling. Tumour tissue correlations were based on usable tissue from eight match paired tumour samples pre- and on therapy, and showed a statistically significant decrease in the median intensity of both pEGFR (P=0.008) and phospho-extracellular signal-regulated kinase (ERK) (P=0.008) a week after commencement of treatment. No other statistically significant change in tumour markers was observed. Erlotinib was well tolerated with the most common toxicities being rash and diarrhoea. More than one-third of evaluable patients had s.d. for a minimum of 8 weeks. Correlative studies showed a reduction in phosphorylated EGFR and ERK in tumour tissue post-treatment.

Adult↗
PubMed2006

A phase II study of perifosine (D-21226) in patients with previously untreated metastatic or locally advanced soft tissue sarcoma: A National Cancer Institute of Canada Clinical Trials Group trial.

UNLABELLED: BACKGROUND/PATIENTS AND METHODS: 16 adult patients with untreated measurable locally advanced or metastatic inoperable soft tissue sarcoma were treated with oral perifosine, a synthetic alkylphospholipid, believed to inhibit MAP kinase (MAP-K), protein kinase C (PKC), Akt and other regulatory proteins. Perifosine was administered orally in cycles for 21 days out of 28. Loading doses were given day 1 each cycle (900 mg cycle 1, 300 mg cycle 2+) and 150 mg daily was given days 2-21 of each cycle. Cycles were repeated until disease progression, unacceptable toxicity or patient refusal. RESULTS: Seventeen patients were enrolled; 16 and 15 were evaluable for toxicity and response, respectively. A total of 30 cycles of perifosine were administered. Most toxic effects were grade 1 or 2 and commonly included nausea, vomiting, diarrhea, and fatigue (> or =40%). Hematologic toxicity was generally mild. There were no significant biochemical abnormalities due to the drug reported. There were 4 serious adverse events (SAE)-none of which was related to perifosine. No objective responses were seen; 4 patients had stable disease for 1.3 to 8.2 months and the remainder of the patients had progressive disease. CONCLUSIONS: Perifosine when given according to this dosing schedule does not show evidence of activity in a mixed population of adult soft tissue sarcoma patients.

Academies and Institutes↗
PubMed2003

Comparison of gemcitabine versus the matrix metalloproteinase inhibitor BAY 12-9566 in patients with advanced or metastatic adenocarcinoma of the pancreas: a phase III trial of the National Cancer Institute of Canada Clinical Trials Group.

PURPOSE: To compare the selective matrix metalloproteinase inhibitor BAY 12-9566 with the nucleoside analog gemcitabine in the treatment of advanced pancreatic cancer. METHODS: Patients with advanced pancreatic adenocarcinoma who had not previously received chemotherapy were randomly assigned to receive BAY 12-9566 800 mg orally bid continuously or gemcitabine 1,000 mg/m2 administered intravenously on days 1, 8, 15, 22, 29, 36, and 43 for the first 8 weeks, and then days 1, 8, and 15 of each subsequent 28-day cycle. The primary end point was overall survival; secondary end points were progression-free survival, tumor response, quality of life, and clinical benefit. The planned sample size of the study was 350 patients. Two formal interim analyses were planned. RESULTS: The study was closed to accrual after the second interim analysis on the basis of the recommendation of the National Cancer Institute of Canada Clinical Trials Group Data Safety Monitoring Committee. There were 277 patients enrolled onto the study, 138 in the BAY 12-9566 arm and 139 in the gemcitabine arm. The rates of serious toxicity were low in both arms. The median survival for the BAY 12-9566 arm and the gemcitabine arm was 3.74 months and 6.59 months, respectively (P <.001; stratified log-rank test). The median progression-free survival for the BAY 12-9566 and gemcitabine arms was 1.68 and 3.5 months, respectively (P <.001). Quality-of-life analysis also favored gemcitabine. CONCLUSION: Gemcitabine is significantly superior to BAY 12-9566 in advanced pancreatic cancer.

Adenocarcinoma↗
PubMed2003

A phase II study of the vitamin D analogue Seocalcitol in patients with inoperable hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a common malignant tumour, which has a poor prognosis. Surgical resection can be curative but most patients are inoperable and most chemotherapy agents have minimal activity in this disease. Seocalcitol, a vitamin D analogue, induces differentiation and inhibits growth in cancer cell lines and in vivo. The vitamin D receptor is expressed in hepatocytes and more abundantly in HCC cells. In total, 56 patients with inoperable advanced HCC were included in an uncontrolled study of oral Seocalcitol treatment for up to 1 year (with possible extension for responders). The dose was titrated according to serum calcium levels. The treatment effect was evaluated by regular CT scans. Out of 33 patients evaluable for tumour response, two had complete response (CR), 12 stable disease and 19 progressive disease. The CRs appeared after 6 and 24 months of treatment, and lasted for 29 and at least 36 months (patient still in remission when data censored). Seocalcitol was well tolerated; the most frequent toxicity was hypercalcaemia and related symptoms. Most patients tolerated a daily dose of 10 micro g of Seocalcitol. This is the first study showing activity, by reduction in tumour dimensions, of a differentiating agent in patients with an advanced bulky, solid tumour. Seocalcitol may have an effect in the treatment of HCC, especially in early disease when a prolonged treatment can be instituted. The survival benefit with or without tumour response should be determined in controlled studies.

Administration, Oral↗
PubMed2001

Phase II study of pemetrexed disodium, a multitargeted antifolate, and cisplatin as first-line therapy in patients with advanced nonsmall cell lung carcinoma: a study of the National Cancer Institute of Canada Clinical Trials Group.

BACKGROUND: Pemetrexed disodium (Alimta [Eli Lilly and Company, Indianapolis, IN], LY231514, multitargeted antifolate) is a new multitargeted antifolate agent that inhibits multiple enzymes in the folate pathway. Phase II trials showed single-agent response rates of 16% and 23% in untreated patients with nonsmall cell lung carcinoma (NSCLC). This study was undertaken to determine the response to pemetrexed disodium given in combination with cisplatin. METHODS: Previously untreated patients were eligible if they had Stage IIIB or IV NSCLC, performance status 0, 1, or 2, adequate hematology and biochemistry and bidimensionally measurable lesions. Patients with brain metastases or neuropathy higher than Grade 2 were excluded. Pemetrexed disodium 500 mg/m(2) was given over 10 minutes, and cisplatin 75 mg/m(2) with hydration and mannitol diuresis was administered on Day 1 of each 21-day cycle. Dexamethasone 4 mg was taken orally once every 12 hours starting 24 hours before treatment and continuing for 6 doses after treatment. Four patients had detailed pemetrexed disodium pharmacokinetic analysis performed. RESULTS: Between May 1998 and June 1999, 31 patients were treated on the study. There were 20 males and 11 females; median age was 60 years (range, 35-75 years); there were 5 Stage IIIB, 26 Stage IV, 26 performance status 0 or 1, and 5 performance status 2. In 29 patients evaluable for response, there were 13 partial responses (PRs; overall response rate [ORR], 95%; confidence interval [CI]: 26-64%) of median duration 6.1 months (1.6-7.8 months). Three of four evaluable patients with performance status 2 achieved PR, and 11 of 24 evaluable Stage IV patients responded (ORR, 45.8% in Stage IV). Eighteen patients died. The median survival rate was 8.9 months (range, 1-15+ months). A total of 160 courses were delivered (median, 6 for both cisplatin and pemetrexed disodium). Grade 3 and 4 anemia was observed in 5 and 1 patients, respectively, and Grade 3 and 4 granulocytopenia in 7 and 4 patients, respectively. Grade 3 nausea and emesis occurred in only 2 patients, Grade 3/4 diarrhea in 3 patients, and 2 patients had Grade 3 motor neuropathy. Nine patients had Grade 2 infections, and there was one case of febrile neutropenia. Pharmacokinetic results showed C(max), clearance and V(ss) values to be similar to data from single-agent pemetrexed disodium given in the same dose. CONCLUSIONS: The combination of pemetrexed disodium and cisplatin is active against advanced NSCLC and is a well-tolerated convenient outpatient regimen. It deserves further study to compare it with other standard regimens for NSCLC.

Adult↗
PubMed2001

Application of a new multinomial phase II stopping rule using response and early progression.

PURPOSE: A multinomial stopping rule had previously been developed that incorporated both objective response and early progression into decisions to stop or continue phase II trials of anticancer agents. The purpose of this study was to apply the multinomial rule to two independent sets of phase II data to assess its utility in appropriately recommending early trial closure as compared with other stopping rules. MATERIALS AND METHODS: Data from completed phase II trials of the National Cancer Institute of Canada Clinical Trials Group (NCIC CTG) and European Organization for Research and Treatment of Cancer Early Clinical Studies Group (ECSG) formed the basis of the study. Based on observed results for each trial, the recommendation of the multinomial stopping rule was applied, as was the recommendation of the actual stopping rule used (Fleming or Gehan). The appropriateness of the recommendations was evaluated based on interpretation of final study results. RESULTS: The standard and multinomial rules disagreed on early stopping in one of 16 NCIC CTG trials and in seven of 23 ECSG trials. In all cases, the standard rule advised continuing to the second stage whereas the multinomial rule advised stopping early because of excessive numbers of patients experiencing early disease progression. Final trial results indicated that the multinomial recommendation was appropriate, because in no study did final results lead to conclusions of activity. CONCLUSION: In this series of trials, the multinomial stopping rule performed more efficiently than the Fleming or Gehan rules in advising early stopping of trials. These results encourage continued exploration of this approach for phase II trials of cytotoxic and noncytotoxic anticancer agents.

Clinical Trials, Phase II as Topic↗
PubMed2001

Impact of new non-cytotoxics in the treatment of ovarian cancer.

Over the last decade, a number of new cytotoxic chemotherapy agents have shown evidence of antitumor activity in patients with ovarian carcinoma. These agents are currently being evaluated in large multinational randomized trials to determine whether their addition either concurrently or sequentially to standard paclitaxel and carboplatin regimens will result in improved survival. Whether these new combinations will provide additional benefit may be uncertain; however, it is certain that additional toxicity will limit the continued evaluation of the strategy of adding cytotoxics together. New approaches to improve the systemic therapy of ovarian cancer need to be explored. The next decade will see many trials of non-cytotoxics having a wide range of subcellular and extracellular targets. Many of these targets are abnormally expressed in a variety of solid tumors; thus, it is expected that many of these agents will be appropriate to evaluate in patients with ovarian carcinoma. Based on promising data from preclinical and early clinical studies as well as the presumed applicability of these targets to ovarian carcinoma, the inhibitors of growth factor receptors such as epidermal growth factor receptor and inhibitors of angiogenesis are of particular interest. Despite the interest of the investigators, the rapid evaluation of these target-specific non-cytotoxics is limited by the lack of accurate information on the expression of target in ovarian tumors and the relevance of target expression and its modulation to this tumor type. Early clinical trials are being designed to address these concerns; however, the clinical impact of non-cytotoxic agents in epithelial ovarian carcinoma patients must await the completion of randomized evaluations in combination with standard chemotherapeutic regimens.

Angiogenesis Inhibitors↗
PubMed2000

Information needs and decisional preferences among women with ovarian cancer.

OBJECTIVES: Studies show that women with cancer want more information about and participation in all aspects of their healthcare including decision-making. However, most studies have been done on women with breast cancer, which often runs a lengthy course and has strong patient-advocacy groups. Little is known about the preferences of women with ovarian cancer, the fifth leading cause of cancer death in women, which often has a more rapidly fatal course. METHODS: This study of women with ovarian cancer investigates what information is most vital for women with ovarian cancer, their preferred role in decision-making, and the influence of sociodemographic, disease-related, and psychological factors. RESULTS: Questionnaires were completed by 105 women with ovarian cancer in two Canadian university hospital oncology clinics. Their mean age was 55.8 +/- 14. 9 years. Most were married, well-educated, and considered their health status to be excellent or good, even though over 60% had metastatic disease. Over 80% of these women wanted detailed information about ovarian cancer during the diagnosis, treatment, and posttreatment stages of their disease. In particular, they wanted information pertaining to the disease, treatment, and self-care issues. Approximately 60% of women preferred to share decision-making with their doctors at every stage of the illness. Psychological variables and disease severity were found to influence information needs and decisional preferences. In general, the more psychologically distressed the women, the more information they wanted about coping strategies and the more serious the illness, the more shared decision-making was desired. CONCLUSION: These results present a challenge to health care providers in more adequately meeting the individual information needs of women with ovarian cancer and involving them to the extent that they wish in the decision-making process.

Adult↗
PubMed2000

Men with prostate cancer: influence of psychological factors on informational needs and decision making.

OBJECTIVES: Studies indicate that men with prostate cancer (MPC) adopt passive roles in cancer management; however, increasing public awareness of prostate cancer and advocacy by MPC and their allies suggest otherwise. This study looks at the information that is important to MPC; their preferred participation in decision making; and the influence of sociodemographic, disease, and psychological factors on information needs and decision preferences. METHOD: Consecutive men diagnosed with prostate cancer and attending two tertiary care cancer clinics completed questionnaires on information needs and decision preferences. Questions included demographic information, health and disease status, psychosocial functioning, optimism, and decisional preferences and information preferences for content, type, focus, format, and amount. RESULTS: Questionnaires were completed by 101 MPC. Their mean age was 70 years and most were married and well-educated. Over 70% wanted detailed information at all illness stages focusing on their disease, treatment, survival, self-care, and empowerment. Over 60% of MPC wanted shared decision making with their physician. Psychological variables were found to influence information needs but not involvement in decision making. CONCLUSION: These results represent a challenge to health-care providers for accomodating the informational needs and decision preferences of individual MPC.

Adaptation, Psychological↗
PubMed2000

A phase I-II study of 9-cis retinoic acid and interferon-alpha2b in patients with advanced renal-cell carcinoma: an NCIC Clinical Trials Group study.

Although advanced renal-cell carcinoma (RCC) responds poorly to standard therapies, phase I-II trials have shown activity for combinations of interferon-alpha2b (IFN) with a retinoid. Alitretinoin (9-cis RA) is an endogenous retinoid with high binding affinity for both RAR and RXR receptor families. This phase I-II study enrolled 38 patients with RCC in a dose-escalation study of tolerability, pharmacokinetics (PK), and efficacy of twice daily oral 9-cis RA with subcutaneous IFN. In contrast to studies with similar doses of daily 9-cis RA, PK studies found a consistent reduction in 9-cis RA concentrations of about 50% after multiple b.i.d. doses of 30 or 50 mg/m2, independent of cotreatment with IFN. In the phase I portion, toxicities included systemic symptoms typical of IFN and biochemical abnormalities previously associated with retinoids. Two patients experienced dose-limiting toxicity at 50 mg/m2 b.i.d. of 9-cis RA, thus the recommended phase II dose was 30 mg/m2 b.i.d. One of twenty-six evaluable patients achieved a durable objective partial remission, and repeated dosing with this regimen was poorly tolerated. This combination of retinoid and interferon is not recommended for further study in RCC.

Adult↗
PubMed2000

Effect of carbohydrate or carbohydrate plus medium-chain triglyceride ingestion on cycling time trial performance.

This study examined the effectiveness of ingesting a carbohydrate or carbohydrate + medium-chain triglycerides (MCT) on metabolism and cycling performance. Eight endurance-trained men [peak O(2) uptake = 4.71 +/- 0.09 (SE) l/min] completed 35 kJ/kg as quickly as possible [time trial (TT)] while consuming 250 ml/15 min of either a 6% (wt/vol) carbohydrate solution (C), a 6% carbohydrate + 4.2% MCT solution (C+M), or a sweet placebo (P). Time to complete the set amount of work was reduced in both C and C+M compared with P by 7 and 5%, respectively (C: 166 +/- 7 min; C+M: 169 +/- 7 min; P: 178 +/- 11 min; P < 0.01). Plasma glucose concentration was maintained at or above resting values throughout both C and C+M trials but decreased (P < 0.05) below resting values in P at the completion of the TT. The estimated rate of carbohydrate oxidation was not different during the first 90 min of exercise but thereafter was reduced (P < 0.05) in P and was maintained in both C and C+M. These data demonstrate that carbohydrate ingestion during exercise improves 100-km TT performance compared with a sweet placebo, but the addition of MCT does not provide any further performance enhancement.

Adult↗
PubMed2000

Prospective randomized trial of docetaxel versus best supportive care in patients with non-small-cell lung cancer previously treated with platinum-based chemotherapy.

PURPOSE: To evaluate whether treatment with single-agent docetaxel would result in longer survival than would best supportive care in patients with non-small-cell lung cancer who had previously been treated with platinum-based chemotherapy. Secondary end points included assessment of response (docetaxel arm only), toxicity, and quality of life. PATIENTS AND METHODS: Patients with performance statuses of 0 to 2 and stage IIIB/IV non-small-cell lung cancer with either measurable or evaluable lesions were eligible for entry onto the study if they had undergone one or more platinum-based chemotherapy regimens and if they had adequate hematology and biochemistry parameters. They were excluded if they had symptomatic brain metastases or if they had previously been treated with paclitaxel. Patients were stratified by performance status and best response to cisplatin chemotherapy and were then randomized to treatment with docetaxel 100 mg/m(2) (49 patients) or 75 mg/m(2) (55 patients) or best supportive care. Patients in both arms were assessed every 3 weeks. RESULTS: One hundred four patients (103 of whom were eligible for entry onto the study) were well balanced for prognostic factors. Of 84 patients with measurable lesions, six (7. 1%) achieved partial responses (three patients at each dose level). Time to progression was longer for docetaxel patients than for best supportive care patients (10.6 v 6.7 weeks, respectively; P <.001), as was median survival (7.0 v 4.6 months; log-rank test, P =.047). The difference was more significant for docetaxel 75 mg/m(2) patients, compared with corresponding best supportive care patients (7.5 v 4.6 months; log-rank test, P =.010; 1-year survival, 37% v 11%; chi(2) test, P =.003). Febrile neutropenia occurred in 11 patients treated with docetaxel 100 mg/m(2), three of whom died, and in one patient treated with docetaxel 75 mg/m(2). Grade 3 or 4 nonhematologic toxicity, with the exception of diarrhea, occurred at a similar rate in both the docetaxel and best supportive care groups. CONCLUSION: Treatment with docetaxel is associated with significant prolongation of survival, and at a dose of 75 mg/m(2), the benefits of docetaxel therapy outweigh the risks.

Adult↗
PubMed2000

Novel therapeutic agents for the treatment of myelodysplastic syndromes.

Few chemotherapy agents have demonstrated activity in patients with myelodysplastic syndromes (MDS) and supportive management remains the standard of care. An increasing number of new drugs in development are being directed at specific molecular or biological targets of these diseases. Topotecan, a topoisomerase I inhibitor, has shown single-agent activity and is now being combined with other agents, including cytarabine. The aminothiol amifostine induces responses in about 30% of patients; however, its role is still being clarified. Agents that inhibit histone deacetylase and target DNA hypermethylation, thus permitting derepression of normal genes, include 5-azacytidine, decitabine, phenylbutyrate, and depsipeptide. Arsenic trioxide has demonstrated impressive activity in acute promyelocytic leukemia and preclinical data suggest the potential for activity in MDS. UCN-01 is a novel agent that inhibits protein kinase C and other protein kinases important for progression through the G1 and G2 phases of the cell cycle. Dolastatin-10 has extremely potent in vitro activity against a variety of tumor cell lines. Since its dose-limiting toxicities include myelosuppression, it is being studied in acute myelogenous leukemia (AML) and MDS. Ras may play a role in MDS, and activation of this gene and its signaling pathways may require farnesylation. Several farnesyl transferase inhibitors are now available for study in patients with MDS. An increasing body of data suggests a possible role for angiogenesis in MDS, and several antiangiogenesis agents are in clinical trials, including thalidomide, SU5416, and anti-vascular endothelial growth factor (VEGF) antibodies. Development of new drugs and regimens will be facilitated by recently developed standardized response criteria. Future clinical trials should focus on rational combinations of these agents and others with the goal of curing patients with MDS.

Antineoplastic Agents↗
PubMed1999

Phase II study of first-line LY231514 (multi-targeted antifolate) in patients with locally advanced or metastatic colorectal cancer: an NCIC Clinical Trials Group study.

BACKGROUND: Metastatic colon cancer is difficult to treat with treatment being palliative and with little effect on survival. This trial has evaluated the effects of LY231514 (Multitargeted antifolate (MTA)) given to previously untreated patients with recurrent or metastatic colorectal carcinoma. PATIENTS AND METHODS: All patients were required to have a histological diagnosis of colorectal adenocarcinoma with measurable disease and no prior chemotherapy for metastatic disease. Patients had to have had performance status of 0-2, pretreatment absolute granulocyte count of > or = 1.5 x 10(9)/l and a platelet count of > or = 150 x 10(9)l. Patients received MTA at a dose of 600 mg/m2 by 10 minute infusion on day 1 repeated every 21 days. After the first 9 patients, this dose was reduced down to 500 mg/m2 every 21 days because of toxicity. Doses of MTA were modified depending on nadir counts. RESULTS: Thirty-two eligible patients were enrolled and twenty-nine were evaluable for response. Three patients did not have repeat radiological testing to determine response because they went off study after only one cycle of treatment due to toxicity. In the 29 evaluable patients, there was 1 complete response, 4 partial responses and 14 patients with stable disease. Response rate was 17.2% (95% confidence intervals: 5.8%-35.8%). All responses occurred in the patients receiving a starting dose of MTA 500 mg/m2. Median time to progression for all eligible patients was 3.3 months. The most common toxicities experienced were mild to moderate fever, lethargy, anorexia, nausea, vomiting, stomatitis, abdominal pain, diarrhea, and skin rash. There was one death due to sepsis. CONCLUSION: Single-agent MTA at 500 mg/m2 given every three weeks has modest activity in metastatic colorectal carcinoma.

Adenocarcinoma↗
PubMed1999

Multinomial phase II cancer trials incorporating response and early progression.

The objective of a phase II clinical trial in oncology is to assess the antitumor activity of a specific treatment regimen. A multiple-testing procedure is commonly used to decide whether the experimental treatment warrants further investigation based on patients' tumor response. There are ethical concerns about exposing patients to a new drug when the response rate is low and a relatively large number of patients have early progressive disease. Ensign et al. (1) proposed a stopping rule that rejects a drug early when there is a long run of early treatment failures. However, this approach may not be sensitive to pick up early progressors mixed with other nonresponders. In this paper, we present a multiple-stage stopping rule for a single-arm trial of an experimental treatment in which both tumor response and early progression are considered simultaneously. We use a multinomial model to accommodate an outcome of discrete multivariate responses in order to improve the efficiency of the stopping rule. The proposed multiple-testing procedure requires that both the numbers of responses and early progressions fall within the boundaries satisfying the stopping criteria in order to stop the study. Simulation is performed to validate these results and to compare them with other commonly used designs. Other applications of this method are also discussed.

Clinical Trials, Phase II as Topic↗
PubMed1999

Skeletal muscle energy metabolism during prolonged, fatiguing exercise.

A depletion of phosphocreatine (PCr), fall in the total adenine nucleotide pool (TAN = ATP + ADP + AMP), and increase in TAN degradation products inosine 5'-monophosphate (IMP) and hypoxanthine are observed at fatigue during prolonged exercise at 70% maximal O(2) uptake in untrained subjects [J. Baldwin, R. J. Snow, M. F. Carey, and M. A. Febbraio. Am. J. Physiol. 277 (Regulatory Integrative Comp. Physiol. 46): R295-R300, 1999]. The present study aimed to examine whether these metabolic changes are also prevalent when exercise is performed below the blood lactate threshold (LT). Six healthy, untrained humans exercised on a cycle ergometer to voluntary exhaustion at an intensity equivalent to 93 +/- 3% of LT ( approximately 65% peak O(2) uptake). Muscle biopsy samples were obtained at rest, at 10 min of exercise, approximately 40 min before fatigue (F-40 =143 +/- 13 min), and at fatigue (F = 186 +/- 31 min). Glycogen concentration progressively declined (P < 0.01) to very low levels at fatigue (28 +/- 6 mmol glucosyl U/kg dry wt). Despite this, PCr content was not different when F-40 was compared with F and was only reduced by 40% when F was compared with rest (52. 8 +/- 3.7 vs. 87.8 +/- 2.0 mmol/kg dry wt; P < 0.01). In addition, TAN concentration was not reduced, IMP did not increase significantly throughout exercise, and hypoxanthine was not detected in any muscle samples. A significant correlation (r = 0.95; P < 0. 05) was observed between exercise time and glycogen use, indicating that glycogen availability is a limiting factor during prolonged exercise below LT. However, because TAN was not reduced, PCr was not depleted, and no correlation was observed between glycogen content and IMP when glycogen stores were compromised, fatigue may be related to processes other than those involved in muscle high-energy phosphagen metabolism.

Adenine Nucleotides↗