Bruno Reigner

Bio: Bruno Reigner is an academic researcher from Hoffmann-La Roche. The author has contributed to research in topics: Capecitabine & Pharmacokinetics. The author has an hindex of 23, co-authored 40 publications receiving 3089 citations.

Preferential activation of capecitabine in tumor following oral administration to colorectal cancer patients.

Abstract: Purpose: Capecitabine (Xeloda) is a novel fluoropyrimidine carbamate rationally designed to generate 5-fluorouracil (5-FU) preferentially in tumors. The purpose of this study was to demonstrate the preferential activation of capecitabine, after oral administration, in tumor in colorectal cancer patients, by the comparison of 5-FU concentrations in tumor tissues, healthy tissues and plasma. Methods: Nineteen patients requiring surgical resection of primary tumor and/or liver metastases received 1,255 mg/m2 of capecitabine twice daily p.o. for 5–7 days prior to surgery. On the day of surgery, samples of tumor tissue, adjacent healthy tissue and blood samples were collected simultaneously from each patient, 2 to 12 h after the last dose of capecitabine had been administered. Concentrations of 5-FU in various tissues and plasma were determined by HPLC. The activities of the enzymes (CD, TP and DPD) involved in the formation and catabolism of 5-FU were measured in tissue homogenates, by catabolic assays. Results: The ratio of 5-FU concentrations in tumor to adjacent healthy tissue (T/H) was used as the primary marker for the preferential activation of capecitabine in tumor. In primary colorectal tumors, the concentration of 5-FU was on average 3.2 times higher than in adjacent healthy tissue (P=0.002). The mean liver metastasis/healthy tissue 5-FU concentration ratio was 1.4 (P=0.49, not statistically different). The mean tissue/plasma 5-FU concentration ratios exceeded 20 for colorectal tumor and ranged from 8 to 10 for other tissues. Conclusions: The results demonstrated the preferential activation of capecitabine to 5-FU in colorectal tumor, after oral administration to patients. This is explained to a great extent by the activity of TP in colorectal tumor tissue, (the enzyme responsible for the conversion of 5′-DFUR to 5-FU), which is approximately four times that in adjacent healthy tissue. In the liver, TP activity is approximately equal in metastatic and healthy tissue, which explains the lack of preferential activation of capecitabine in these tissues.

Clinical Pharmacokinetics of Capecitabine

Abstract: Capecitabine is a novel oral fluoropyrimidine carbamate that is preferentially converted to the cytotoxic moiety fluorouracil (5-fluorouracil; 5-FU) in target tumour tissue through a series of 3 metabolic steps. After oral administration of 1250 mg/m2, capecitabine is rapidly and extensively absorbed from the gastrointestinal tract [with a time to reach peak concentration (tmax) of 2 hours and peak plasma drug concentration (Cmax) of 3 to 4 mg/L] and has a relatively short elimination half-life (t1/2) [0.55 to 0.89h]. Recovery of drug-related material in urine and faeces is nearly 100%.

Phase I and pharmacologic study of intermittent twice-daily oral therapy with capecitabine in patients with advanced and/or metastatic cancer.

Abstract: PURPOSECapecitabine is an orally administered fluoropyrimidine carbamate selectively activated to fluorouracil (5-FU) in tumors. It passes through the intestinal mucosal membrane intact and is subsequently activated by a cascade of three enzymes that results in the preferential release of 5-FU at the tumor site.PATIENTS AND METHODSIn this phase I study, capecitabine was administered twice daily as outpatient therapy, each cycle administered for 2 weeks followed by 1 week of rest. Thirty-four patients with solid tumors, all of whom except three patients were pretreated, were treated at dose levels from 502 to 3,514 mg/m2 daily.RESULTSThe median treatment duration was four cycles (85 days; range, 14 to 833+ days). Two patients continue on treatment at 686 and 833+ days. Capecitabine 3,000 mg/m2 daily was not tolerable, with dose-limiting toxicities of diarrhea with hypotension, abdominal pain, and leukopenia. Palmar-plantar erythrodysesthesia (PPE) became evident at higher dose levels after prolonged treatm...

Pharmacokinetics and Pharmacodynamics of Intravenous and Subcutaneous Continuous Erythropoietin Receptor Activator (C.E.R.A.) in Patients with Chronic Kidney Disease

Abstract: Continuous Erythropoietin Receptor Activator (C.E.R.A.) is a new agent that is in development for the treatment of anemia with extended administration intervals in patients who have chronic kidney disease (CKD), both those on and those not on dialysis. This was an open-label, randomized, multicenter, two-period, crossover study in erythropoiesis-stimulating agentnaive patients who had CKD and anemia and were receiving peritoneal dialysis. After a 1-wk run-in period, 16 patients were randomly assigned to receive a single administration of intravenous C.E.R.A. 0.4 microg/kg (n = 8) or subcutaneous C.E.R.A. 0.8 microg/kg (n = 8). Six weeks after the first administration of C.E.R.A. (4-wk assessment, 2-wk washout), the route of administration was switched so that all patients received single administrations of both intravenous C.E.R.A. 0.4 microg/kg and subcutaneous C.E.R.A. 0.8 microg/kg. C.E.R.A. had a prolonged and comparable half-life after intravenous (mean 134 h) and subcutaneous (mean 139 h) administration. Reticulocyte counts peaked at a median of 8 d after intravenous and subcutaneous administration with no difference in the time course between administration routes. This resulted in similar mean values for the area under the reticulocyte count-time curve (1191 x 10(9) and 1193 x 10(9).d per L, respectively) and the maximum absolute increase in reticulocyte counts (36 x 10(9) and 41 x 10(9)/L, respectively). C.E.R.A. has a prolonged and comparable half-life after intravenous or subcutaneous injection, suggesting that extended administration intervals may be feasible in patients with CKD.

Prediction of hepatic metabolic clearance based on interspecies allometric scaling techniques and in vitro-in vivo correlations.

Abstract: This article reviews the methods available for predicting hepatic metabolic clearance in humans, and discusses their application to the processes of drug discovery and development. The application of these techniques has increased markedly during the past few years because of the improved availability of human liver samples, which has increased the opportunities to use in vitro studies to predict human clearance. The techniques available involve both empirical and physiologically based approaches. Allometric scaling using in vitro data from animals and humans combines certain aspects of both approaches. An evaluation of data retrieved from the literature indicates that, together with in vitro human data, allometric scaling based on a combination of in vitro and in vivo preclinical data can accurately predict clearance in humans. With this approach, 80% of the predictions were within a 2-fold factor of actual human clearance values, with an overall accuracy of 1.6-fold. The uncertainties and inaccuracies in predicting human clearance are related to: (i) the specific method that is used to make the prediction; (ii) the experimental design and the model used to determine the in vitro clearance; (iii) protein binding within the in vitro test system; and (iv) various in vivo factors such as the involvement of extrahepatic metabolism and active transport processes, interindividual variability and nonlinearity in pharmacokinetics. In contrast to purely empirical approaches, the physiological approach to predicting clearance gives an opportunity to integrate some of these complexities and, therefore, should provide more confidence in the prediction of clearance in humans.

5-Fluorouracil: mechanisms of action and clinical strategies

Abstract: 5-fluorouracil (5-FU) is widely used in the treatment of cancer. Over the past 20 years, increased understanding of the mechanism of action of 5-FU has led to the development of strategies that increase its anticancer activity. Despite these advances, drug resistance remains a significant limitation to the clinical use of 5-FU. Emerging technologies, such as DNA microarray profiling, have the potential to identify novel genes that are involved in mediating resistance to 5-FU. Such target genes might prove to be therapeutically valuable as new targets for chemotherapy, or as predictive biomarkers of response to 5-FU-based chemotherapy.

A simple practice guide for dose conversion between animals and human.

Abstract: Understanding the concept of extrapolation of dose between species is important for pharmaceutical researchers when initiating new animal or human experiments. Interspecies allometric scaling for dose conversion from animal to human studies is one of the most controversial areas in clinical pharmacology. Allometric approach considers the differences in body surface area, which is associated with animal weight while extrapolating the doses of therapeutic agents among the species. This review provides basic information about translation of doses between species and estimation of starting dose for clinical trials using allometric scaling. The method of calculation of injection volume for parenteral formulation based on human equivalent dose is also briefed.

Recurrent Epithelial Ovarian Carcinoma: A Randomized Phase III Study of Pegylated Liposomal Doxorubicin Versus Topotecan

Abstract: PURPOSE: To compare the efficacy and safety of pegylated liposomal doxorubicin (PLD) and topotecan in patients with epithelial ovarian carcinoma that recurred after or didn’t respond to first-line, platinum-based chemotherapy. PATIENTS AND METHODS: Patients with measurable and assessable disease were randomized to receive either PLD 50 mg/m2 as a 1-hour infusion every 4 weeks or topotecan 1.5 mg/m2/d for 5 consecutive days every 3 weeks. Patients were stratified prospectively for platinum sensitivity and for the presence or absence of bulky disease. RESULTS: A total of 474 patients were treated (239 PLD and 235 topotecan). They comprised the intent-to-treat population. The overall progression-free survival rates were similar between the two arms (P = .095). The overall response rates for PLD and topotecan were 19.7% and 17.0%, respectively (P = .390). Median overall survival times were 60 weeks for PLD and 56.7 weeks for topotecan. Data analyzed in platinum-sensitive patients demonstrated a statistically ...

Capecitabine as Adjuvant Treatment for Stage III Colon Cancer

Abstract: BACKGROUND Intravenous bolus fluorouracil plus leucovorin is the standard adjuvant treatment for colon cancer. The oral fluoropyrimidine capecitabine is an established alternative to bolus fluorouracil plus leucovorin as first-line treatment for metastatic colorectal cancer. We evaluated capecitabine in the adjuvant setting. METHODS We randomly assigned a total of 1987 patients with resected stage III colon cancer to receive either oral capecitabine (1004 patients) or bolus fluorouracil plus leucovorin (Mayo Clinic regimen; 983 patients) over a period of 24 weeks. The primary efficacy end point was at least equivalence in disease-free survival; the primary safety end point was the incidence of grade 3 or 4 toxic effects due to fluoropyrimidines. RESULTS Disease-free survival in the capecitabine group was at least equivalent to that in the fluorouracil-plus-leucovorin group (in the intention-to-treat analysis, P<0.001 for the comparison of the upper limit of the hazard ratio with the noninferiority margin of 1.20). Capecitabine improved relapse-free survival (hazard ratio, 0.86; 95 percent confidence interval, 0.74 to 0.99; P=0.04) and was associated with significantly fewer adverse events than fluorouracil plus leucovorin (P<0.001). CONCLUSIONS Oral capecitabine is an effective alternative to intravenous fluorouracil plus leucovorin in the adjuvant treatment of colon cancer.

Comparison of Oral Capecitabine Versus Intravenous Fluorouracil Plus Leucovorin as First-Line Treatment in 605 Patients With Metastatic Colorectal Cancer: Results of a Randomized Phase III Study

Abstract: PURPOSE: To compare the response rate, efficacy parameters, and toxicity profile of oral capecitabine with bolus intravenous (IV) fluorouracil plus leucovorin (5-FU/LV) as first-line treatment in patients with metastatic colorectal cancer. PATIENTS AND METHODS: We prospectively randomized 605 patients to treatment with oral capecitabine for 14 days every 3 weeks or 5-FU/LV by rapid IV injection daily for 5 days in 4-week cycles. RESULTS: The overall objective tumor response rate among all randomized patients was significantly higher in the capecitabine group (24.8%) than in the 5-FU/LV group (15.5%; P = .005). In the capecitabine and 5-FU/LV groups, median times to disease progression were 4.3 and 4.7 months (log-rank P = .72), median times to treatment failure were 4.1 and 3.1 months (P = .19), and median overall survival times were 12.5 and 13.3 months (P = .974), respectively. Capecitabine, compared with bolus 5-FU/LV treatment, produced a significantly lower incidence (P < .0002) of diarrhea, stomatit...