Comprehensive pharmaceutical care to prevent drug-related readmissions of dependent-living elderly patients: a randomized controlled trial.

BACKGROUND: Elderly patients are vulnerable to adverse drug reactions (ADRs). Drug-related readmissions (DRRs) can be a major consequence of ADR. Therefore, this study aimed to investigate the effects of a ward-based, comprehensive pharmaceutical care service on the occurrence of DRRs as the endpoint in dependent-living elderly patients. METHODS: A randomized, controlled trial was performed at a German University Hospital. Patients fulfilling the following criteria were eligible: admission to a cooperating ward, existing drug therapy at admission, 65 years of age and older, home-care or nursing home residents in ambulatory care, and a minimum hospital stay of three days. Patients received either standard care (control group) or pharmaceutical care (intervention group). Follow-up consultations were conducted for each patient at 1, 8, 26, and 52 weeks after discharge. The time to DRR was defined as the primary outcome measure and was analysed using the log-rank test. The Cox-proportional hazard model was used for risk factor analysis. RESULTS: Sixty patients (n = 31 intervention group, n = 29 control group) participated in the study. For patients in the intervention group, the median time to DRR was prolonged; however, the level of statistical significance was not reached (log-rank test P = 0.068; HR = 3.28, P = 0.086). When the risk factors 'age' or 'length of stay on the ward' were added to the Cox proportional hazard model, patients in the control group exhibited a significantly higher risk of experiencing a DRR than patients of the intervention group (HR = 4.62; P = 0.028 including age and HR = 5.76; P = 0.033 including length of stay on the ward). CONCLUSIONS: Our findings demonstrate the successful implementation of ward-based, comprehensive pharmaceutical care for dependent-living elderly. Despite a low participation rate, which led to an underpowered study, the results provide a preliminary efficacy signal and effect size estimates to power a definitive trial. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT01578525 , prospectively registered April 13, 2012.

Population Modeling Integrating Pharmacokinetics, Pharmacodynamics, Pharmacogenetics, and Clinical Outcome in Patients With Sunitinib-Treated Cancer.

The tyrosine kinase inhibitor sunitinib is used as first-line therapy in patients with metastasized renal cell carcinoma (mRCC), given in fixed-dose regimens despite its high variability in pharmacokinetics (PKs). Interindividual variability of drug exposure may be responsible for differences in response. Therefore, dosing strategies based on pharmacokinetic/pharmacodynamic (PK/PD) models may be useful to optimize treatment. Plasma concentrations of sunitinib, its active metabolite SU12662, and the soluble vascular endothelial growth factor receptors sVEGFR-2 and sVEGFR-3, were measured in 26 patients with mRCC within the EuroTARGET project and 21 patients with metastasized colorectal cancer (mCRC) from the C-II-005 study. Based on these observations, PK/PD models with potential influence of genetic predictors were developed and linked to time-to-event (TTE) models. Baseline sVEGFR-2 levels were associated with clinical outcome in patients with mRCC, whereas active drug PKs seemed to be more predictive in patients with mCRC. The models provide the basis of PK/PD-guided strategies for the individualization of anti-angiogenic therapies.

Validation of the German patient-reported outcomes version of the common terminology criteria for adverse events (PRO-CTCAE™).

BACKGROUND: Integrating the patient's perspective has become an increasingly important component of adverse event reporting. The National Cancer Institute has developed a Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE™). This instrument has been translated into German and linguistically validated; however, its quantitative measurement properties have not been evaluated. PATIENTS AND METHODS: A German language survey that included 31 PRO-CTCAE items, as well as the EORTC QLQ-C30 and the Oral Mucositis Daily Questionnaire (OMDQ), was distributed at 10 cancer treatment settings in Germany and Austria. Item quality was assessed by analysis of acceptability and comprehensibility. Reliability was evaluated by using Cronbach's' alpha and validity by principal components analysis (PCA), multitrait-multimethod matrix (MTMM) and known groups validity techniques. RESULTS: Of 660 surveys distributed to the study centres, 271 were returned (return rate 41%), and data from 262 were available for analysis. Participants' median age was 59.7 years, and 69.5% of the patients were female. Analysis of item quality supported the comprehensibility of the 31 PRO-CTCAE items. Reliability was very good; Cronbach's' alpha correlation coefficients were >0.9 for almost all item clusters. Construct validity of the PRO-CTCAE core item set was shown by identifying 10 conceptually meaningful item clusters via PCA. Moreover, construct validity was confirmed by the MTMM: monotrait-heteromethod comparison showed 100% high correlation, whereas heterotrait-monomethod comparison indicated 0% high correlation. Known groups validity was supported; PRO-CTCAE scores were significantly lower for those with impaired versus preserved health-related quality of life. CONCLUSION: A set of 31 items drawn from the German PRO-CTCAE item library demonstrated favourable measurement properties. These findings add to the body of evidence that PRO-CTCAE provides a rigorous method to capture patient self-reports of symptomatic toxicity for use in cancer clinical trials.

Open-label, randomized study of individualized, pharmacokinetically (PK)-guided dosing of paclitaxel combined with carboplatin or cisplatin in patients with advanced non-small-cell lung cancer (NSCLC).

BACKGROUND: Variable chemotherapy exposure may cause toxicity or lack of efficacy. This study was initiated to validate pharmacokinetically (PK)-guided paclitaxel dosing in patients with advanced non-small-cell lung cancer (NSCLC) to avoid supra- or subtherapeutic exposure. PATIENTS AND METHODS: Patients with newly diagnosed, advanced NSCLC were randomly assigned to receive up to 6 cycles of 3-weekly carboplatin AUC 6 or cisplatin 80 mg/m(2) either with standard paclitaxel at 200 mg/m(2) (arm A) or PK-guided dosing of paclitaxel (arm B). In arm B, initial paclitaxel dose was adjusted to body surface area, age, sex, and subsequent doses were guided by neutropenia and previous-cycle paclitaxel exposure [time above a plasma concentration of 0.05 µM (Tc>0.05)] determined from a single blood sample on day 2. The primary end point was grade 4 neutropenia; secondary end points included neuropathy, radiological response, progression-free survival (PFS) and overall survival (OS). RESULTS: Among 365 patients randomly assigned, grade 4 neutropenia was similar in both arms (19% versus 16%; P = 0.10). Neuropathy grade ≥2 (38% versus 23%, P < 0.001) and grade ≥3 (9% versus 2%, P < 0.001) was significantly lower in arm B, independent of the platinum drug used. The median final paclitaxel dose was significantly lower in arm B (199 versus 150 mg/m(2), P < 0.001). Response rate was similar in arms A and B (31% versus 27%, P = 0.405), as was adjusted median PFS [5.5 versus 4.9 months, hazard ratio (HR) 1.16, 95% confidence interval (CI) 0.91-1.49, P = 0.228] and OS (10.1 versus 9.5 months, HR 1.05, 95% CI 0.81-1.37, P = 0.682). CONCLUSION: PK-guided dosing of paclitaxel does not improve severe neutropenia, but reduces paclitaxel-associated neuropathy and thereby improves the benefit-risk profile in patients with advanced NSCLC. CLINICAL TRIAL INFORMATION: NCT01326767 (https://clinicaltrials.gov/ct2/show/NCT01326767).

Doripenem Treatment during Continuous Renal Replacement Therapy.

Doripenem is a broad-spectrum parenteral carbapenem with enhanced activity against Pseudomonas aeruginosa. While the initial dosing recommendation for renally competent patients and patients undergoing continuous renal replacement therapy (cRRT) was 500 mg every 8 h (q8h), the dose for renally competent patients was updated to 1 g q8h in June 2012. There are no updated data for the dosing of patients on continuous renal replacement therapy. The original dosing regimen for cRRT patients was based on nonseptic patients, while newer publications chose comparatively low target concentrations for a carbapenem. Thus, there is an urgent need for updated recommendations for dosing during cRRT. In the trial presented here, we included 13 oliguric septic patients undergoing cRRT in an intensive care setting. Five patients each were treated with hemodiafiltration or hemodialysis, while three patients received hemofiltration treatment. All patients received 1 g doripenem every 8 h. Doripenem concentrations in the plasma and ultrafiltrate were measured over 48 h. The mean hemofilter clearance was 36.53 ml/min, and the mean volume of distribution was 59.26 liters. The steady-state trough levels were found at 8.5 mg/liter, with no considerable accumulation. Based on pharmacokinetic and pharmacodynamic considerations, we propose a regimen of 1 g q8h, which may be combined with a loading dose of 1.5 to 2 g for critically ill patients. (This study has been registered with EudraCT under registration no. 2009-018010-18 and at ClinicalTrials.gov under registration no. NCT02018939.).

Defining the role of MRP-mediated efflux and glutathione in detoxification of oxaliplatin.

Albeit platinum complexes are widely used in cancer chemotherapy, their cellular processing has not been completely elucidated so far. In this study the effects of modulating multidrug resistance-associated protein (MRP)-mediated efflux and glutathione (GSH) depletion on the cytotoxicity of oxaliplatin were assessed in a human ileocecal colorectal adenocarcinoma cell line and its oxaliplatin-resistant variant. Upon oxaliplatin exposure, DNA platination was elevated by co-incubation with Gü83, a MRP1 and MRP2 inhibitor, but cytotoxicity was not increased. Addition of oxaliplatin did not alter the cellular GSH content. Following GSH depletion, platinum accumulation was unchanged but cytotoxicity was increased in oxaliplatin-sensitive cells. In conclusion, modulation of MRP-mediated efflux did not affect oxaliplatin cytotoxicity in the investigated cell lines. Intracellular GSH depletion seems to sensitize the cells but does not overcome resistance.

[Compliance enhancement in drug therapy : opportunities and limitations]. / Complianceförderung in der Arzneimitteltherapie : Chancen und Grenzen.

In the execution of their pharmacotherapy, many patients deviate from the prescribed treatment regimen. Reasons for noncompliance can be diverse and range from forgetfulness of the patient to attributes of the health care system. Besides increased health care costs, poor compliance causes both an endangerment to the patient and poor health outcomes. Therefore, it is crucial that compliance enhancement receives high priority. In the beginning of this process, noncompliance must be detected in daily practice. Moreover, various methods can provide valuable information about medication-taking behavior, time patterns, and reasons for noncompliance. Based on this assessment, appropriate measures to enhance compliance can be taken. In this article, the opportunities and limitations of compliance enhancement are discussed.

Assessment of activity levels for CYP2D6*1, CYP2D6*2, and CYP2D6*41 genes by population pharmacokinetics of dextromethorphan.

The pharmacokinetics of dextromethorphan (DM) is markedly influenced by cytochrome P450 2D6 (CYP2D6) enzyme polymorphisms. The aim of this study was to quantify the effects of the CYP2D6*1, *2, and *41 variants on DM metabolism in vivo and to identify other sources of pharmacokinetic variability. Concentrations of DM and dextrorphan (DO) in plasma and urine were evaluated in 36 healthy Caucasian men. These volunteers participated in three clinical studies and received a single oral dose of 30 mg DM-HBr. Data were modeled simultaneously using the population pharmacokinetics NONMEM software. A five-compartment model adequately described the data. The activity levels of the alleles assessed differed significantly. The clearance attributable to an individual CYP2D6*1 copy was 2.5-fold higher as compared with CYP2D6*2 (5,010 vs. 2,020 l/h), whereas the metabolic activity of CYP2D6*41 was very low (85 l/h). Urinary pH was confirmed as a significant covariate for DM renal clearance. These results refine genotype-based predictions of pharmacokinetics for DM and presumably for other CYP2D6 substrates as well.

Pharmacokinetic/pharmacodynamic modeling of biomarker response to sunitinib in healthy volunteers.

A pharmacokinetic/pharmacodynamic (PK/PD) study of the tyrosine kinase inhibitor sunitinib was conducted in 12 healthy volunteers using blood pressure and circulating biomarker levels as PD markers. Blood pressure was measured, and plasma concentration-time courses of sunitinib, its major metabolite SU12662, vascular endothelial growth factors VEGF-A and VEGF-C, and soluble VEGF receptor-2 (sVEGFR-2) were studied in healthy subjects receiving 50 mg of sunitinib orally for 3-5 consecutive days. Using NONMEM, PK/PD models were established that predicted changes (expressed as multiples relative to baseline values) in systolic blood pressure, diastolic blood pressure, VEGF-A level, and sVEGFR-2 level, of 1.10, 1.18, 2.24, and 0.76, respectively, for a typical subject after 4 weeks of treatment with 50 mg/day. Simulated blood pressure-time courses compare excellently with published data in patients, whereas changes in circulating biomarkers were greater in patients than simulations suggest for healthy subjects. In conclusion, the tumor-independent pharmacological response to sunitinib could be described by PK/PD models, thereby facilitating model-based investigations with antiangiogenic drugs, using blood pressure and circulating proteins as biomarkers.

Oxaliplatin-DNA adduct formation in white blood cells of cancer patients.

In this study, we investigated the kinetics of oxaliplatin-DNA adduct formation in white blood cells of cancer patients in relation to efficacy as well as oxaliplatin-associated neurotoxicity. Thirty-seven patients with various solid tumours received 130 mg m(-2) oxaliplatin as a 2-h infusion. Oxaliplatin-DNA adduct levels were measured in the first cycle using adsorptive stripping voltammetry. Platinum concentrations were measured in ultrafiltrate and plasma using a validated flameless atomic absorption spectrometry method. DNA adduct levels showed a characteristic time course, but were not correlated to platinum pharmacokinetics and varied considerably among individuals. In patients showing tumour response, adduct levels after 24 and 48 h were significantly higher than in nonresponders. Oxaliplatin-induced neurotoxicity was more pronounced but was not significantly different in patients with high adduct levels. The potential of oxaliplatin-DNA adduct measurements as pharmacodynamic end point should be further investigated in future trials.

Marked elevation in homocysteine and homocysteine sulfinic acid in the cerebrospinal fluid of lymphoma patients receiving intensive treatment with methotrexate.

OBJECTIVE: Interference of methotrexate (MTX) with the metabolism of homocysteine may contribute to MTX neurotoxicity. In this pilot study we measured the concentration of homocysteine and related metabolites in the cerebrospinal fluid (CSF) of patients with primary central nervous system lymphoma undergoing intensive treatment with MTX. MATERIAL AND METHODS: CSF samples from lymphoma patients (n = 4) were drawn at the end of high-dose MTX infusions (3-5 g/m2/24 h, HDMTX) and one day after intraventricular injections of MTX (3 mg, ICVMTX) or cytarabine (30 mg) and analyzed for homocysteine, cysteine, sulfur-containing excitatory amino acids (cysteine sulfinic acid, cysteic acid, homocysteine sulfinic acid and homocysteic acid), S-adenosylmethionine, 5-methyltetrahydrofolate and MTX. The concentration of homocysteine, cysteine and sulfur-containing excitatory amino acids were also measured in the CSF of a reference population not exposed to MTX. The Wilcoxon signed rank-test and the Friedman test were used to compare concentrations of homocysteine and its metabolites at various time-points during chemotherapy. Comparison of patient and control samples were performed using the Mann-Whitney U-test. Allelic variants of homocysteine metabolism previously shown to influence MTX neurotoxicity (MTHFR c.677C>T, MS c.2756A>G and Tc2 c.776C>G) were also analyzed. RESULTS: After application of HD- and ICVMTX, the CSF homocysteine concentrations in the lymphoma patients were markedly elevated and significantly higher than those in the control group (p < 0.05, Mann-Whitney U-test), whereas 5-methyltetrahydrofolate was depleted. A rapid elevation of homocysteine sulfinic acid, a sulfur-containg amino acid which was not detected in the CSF of the control group, was observed. One patient developed confluent white matter brain changes visible using MRI. This patient had the lowest concentration of S-adenosylmethionine in the CSF and carried two risk alleles for MTX neurotoxicity. CONCLUSIONS: In this pilot study, MTX administered either intravenously or intraventricularly, induced marked biochemical alterations in the CSF. Whether these changes can be used to predict MTX-induced neurotoxicity at an early stage in treatment needs to be elucidated in larger clinical trials.

Evaluation of probe drugs and pharmacokinetic metrics for CYP2D6 phenotyping.

INTRODUCTION: Cytochrome P450 2D6 (CYP2D6) is one of the most important enzymes catalyzing biotransformation of xenobiotics in the human liver. This enzyme's activity shows a high degree of interindividual variability caused in part by its genetic polymorphism, the so-called debrisoquine/sparteine polymorphism. The genetic component influencing CYP2D6 activity can be determined by genotyping. However, genotyping alone is not sufficient to accurately predict an individual's actual CYP2D6 activity, as this is also influenced by other factors. For the determination of the exact actual enzymatic activity ("phenotyping"), adequate probe drugs have to be administered prior to measurements of these compounds and/or their metabolites in body fluids. PROBE DRUGS: Debrisoquine, sparteine, metoprolol or dextromethorphan represent well-established probe drugs while tramadol has been recently investigated for this purpose. The enzymatic activity is reflected by various pharmacokinetic metrics such as the partial clearance of a parent compound to the respective CYP2D6-mediated metabolite or metabolic ratios. Appropriate metrics need to fulfill pre-defined validation criteria. METHODS: In this review, we have compiled a list of such criteria useful to select the best metrics to reflect CYP2D6 activity. A comprehensive Medline search for reports on CYP2D6 phenotyping trials with the above mentioned probe drugs was carried out. CONCLUSION: Application of the validation criteria suggests that dextromethorphan and debrisoquine are the best CYP2D6 phenotyping drugs, with debrisoquine having the problem of very limited availability as a therapeutic drug. However, the assessment of the best dextromethorphan CYP2D6 phenotyping metric/procedure is still ongoing.