Longitudinal Analysis of the Effect of Inflammation on Voriconazole Trough Concentrations.

Voriconazole (VCZ) exhibits great inter- and intrapatient variability. The latter variation cannot exclusively be explained by concomitant medications, liver disease or dysfunction, and genetic polymorphisms in cytochrome P450 2C19 (CYP2C19). We hypothesized that inflammatory response in patients under VCZ medication might also influence this fluctuation in concentrations. In this study, we explored the association between inflammation, reflected by the C-reactive protein (CRP) concentration, and VCZ trough concentrations over time. A retrospective analysis of data was performed for patients with more than one steady-state VCZ trough concentration and a CRP concentration measured on the same day. A longitudinal analysis was used for series of observations obtained from many study participants over time. The approach involved inclusion of random effects and autocorrelation in linear models to reflect within-person cross-time correlation. A total of 50 patients were eligible for the study, resulting in 139 observations (paired VCZ and CRP concentrations) for the analysis, ranging from 2 to 6 observations per study participant. Inflammation, marked by the CRP concentration, had a significant association with VCZ trough concentrations (P < 0.001). Covariates such as age and interacting comedication ([es]omeprazole), also showed a significant correlation between VCZ and CRP concentrations (P < 0.05). The intrapatient variation of trough concentrations of VCZ was 1.401 (confidence interval [CI], 0.881 to 2.567), and the interpatient variation was 1.756 (CI, 0.934 to 4.440). The autocorrelation between VCZ trough concentrations at two sequential time points was calculated at 0.71 (CI, 0.51 to 0.92). The inflammatory response appears to play a significant role in the largely unpredictable pharmacokinetics of VCZ, especially in patients with high inflammatory response, as reflected by high CRP concentrations.

Long-term exposure to circulating platinum is associated with late effects of treatment in testicular cancer survivors.

BACKGROUND: The success of cisplatin-based (Platinol, Bristol-Myers Squibb Company, New York, NY, USA) chemotherapy for testicular cancer comes at the price of long-term and late effects related to healthy tissue damage. We assessed and modelled serum platinum (Pt) decay after chemotherapy and determined relationships between long-term circulating Pt levels and known late effects. PATIENTS AND METHODS: In 99 testicular cancer survivors, treated with cisplatin-based chemotherapy, serum and 24-h urine samples were collected during follow-up (1-13 years after treatment). To build a population pharmacokinetic model, measured Pt data were simultaneously analysed, together with cisplatin dose, age, weight and height using the NONMEM software. Based on this model, area under the curve between 1 and 3 years after treatment (Pt AUC1-3 years) was calculated for each patient. Predicted long-term Pt exposure was related to renal function and to late effects of treatment assessed median 9 (3-15) years after chemotherapy. RESULTS: Decay of Pt was best described by a two-compartment model. Mean terminal T1/2 was 3.7 (range 2.5-5.2) years. Pt AUC1-3 years correlated with cumulative cisplatin dose, and creatinine clearance before and 1 year after treatment. Patients with paraesthesia had higher Pt AUC1-3 years (30.9 versus 27.0 µg/l month) compared with those without paraesthesia (P = 0.021). Patients with hypogonadism, elevated LDL-cholesterol levels or hypertension also had higher Pt AUC1-3 years. CONCLUSIONS: Renal function before and after cisplatin treatment is an important determinant of long-term Pt exposure. Known long-term effects of testicular cancer treatment, such as paraesthesia, hypogonadism, hypercholesterolaemia and hypertension, are associated with long-term circulating Pt exposure.

Five year results of an international proficiency testing programme for measurement of antifungal drug concentrations.

OBJECTIVES: Since 2007 the Dutch Association for Quality Assessment in Therapeutic Drug Monitoring (KKGT) has organized an international interlaboratory proficiency testing (PT) programme for measurement of antifungal drugs in plasma. We describe the 5 year results of the laboratories' performance. METHODS: Twice a year, laboratories received a set of blind plasma samples containing low or high concentrations of fluconazole, itraconazole, hydroxyitraconazole, posaconazole, voriconazole and flucytosine. Participating laboratories were asked to report their results within 6 weeks after dispatch and provide details of their analytical methods. Results deviating >20% from the weighed-in concentration were considered inaccurate. Four-way ANOVA was performed to assess the effect of antifungal drug measured, concentration, analytical method and performing laboratory on the absolute inaccuracy. In 2012, a questionnaire based on the CLSI guidelines was dispatched with the request to provide input on sources of error. RESULTS: Fifty-seven laboratories (13 countries) reported 2251 results (287 fluconazole, 451 itraconazole, 348 hydroxyitraconazole, 402 posaconazole, 652 voriconazole and 111 flucytosine) in 5 years. Analyses were performed using HPLC (55.0%), LC-MS(/MS) (43.4%), UPLC (1.4%) or GC-MS (0.2%). Overall, 432 (19.2%) analyses were inaccurate. The performing laboratory was the only factor clearly associated with inaccuracies. The questionnaire results indicated that laboratories encounter significant problems analysing low concentrations (15.4% of all inaccuracies). CONCLUSIONS: Results of the PT programme suggest that one out of five measurements is inaccurate. The performing laboratory is the main determinant of inaccuracy, suggesting that internal quality assurance is pivotal in preventing inaccuracies, irrespective of the antifungal drug measured, concentration and analytical equipment.

Clinical validation of the analysis of linezolid and clarithromycin in oral fluid of patients with multidrug-resistant tuberculosis.

Linezolid plays an increasingly important role in the treatment of multidrug-resistant tuberculosis (MDR-TB). However, patients should be carefully monitored due to time- and dose-dependent toxicity. Clarithromycin plays a more modest role. Therapeutic drug monitoring may contribute to assessment of treatment regimens, helping to reduce toxicity while maintaining adequate drug exposure. Oral fluid sampling could provide a welcome alternative in cases where conventional plasma sampling is not possible or desirable. The aim of this study was to clinically validate the analysis of linezolid and clarithromycin and its metabolite hydroxyclarithromycin in oral fluid of patients with multidrug-resistant tuberculosis. Serum and oral fluid samples were simultaneously obtained and analyzed by using validated methods, after extensive cross-validation between the two matrices. Passing-Bablok regressions and Bland-Altman analysis showed that oral fluid analysis of linezolid and clarithromycin appeared to be suitable for therapeutic drug monitoring in MDR-TB patients. No correction factor is needed for the interpretation of linezolid oral fluid concentrations with a ratio of the linezolid concentration in serum to that in oral fluid of 0.97 (95% confidence interval [CI], 0.92 to 1.02). However, the clarithromycin concentration serum/clarithromycin concentration in oral fluid ratio is 3.07 (95% CI, 2.45 to 3.69). Analysis of hydroxyclarithromycin in oral fluid was not possible in this study due to a nonlinear relationship between the concentration in serum and that in oral fluid. In conclusion, the analysis of linezolid (no correction factor) and clarithromycin (correction factor of 3) in oral fluid is applicable for therapeutic drug monitoring in cases of multidrug-resistant tuberculosis as an alternative to conventional serum sampling. Easy sampling using a noninvasive technique may facilitate therapeutic drug monitoring for specific patient categories.

Dried blood spot analysis for therapeutic drug monitoring of linezolid in patients with multidrug-resistant tuberculosis.

Linezolid is a promising antimicrobial agent for the treatment of multidrug-resistant tuberculosis (MDR-TB), but its use is limited by toxicity. Therapeutic drug monitoring (TDM) may help to minimize toxicity while adequate drug exposure is maintained. Conventional plasma sampling and monitoring might be hindered in many parts of the world by logistical problems that may be solved by dried blood spot (DBS) sampling. The aim of this study was to develop and validate a novel method for TDM of linezolid in MDR-TB patients using DBS sampling. Plasma, venous DBS, and capillary DBS specimens were obtained simultaneously from eight patients receiving linezolid. A DBS sampling method was developed and clinically validated by comparing DBS with plasma results using Passing-Bablok regression and Bland-Altman analysis. This study showed that DBS analysis was reproducible and robust. Accuracy and between- and within-day precision values from three validations presented as bias and coefficient of variation (CV) were less than 17.2% for the lower limit of quantification and less than 7.8% for other levels. The method showed a high recovery of approximately 95% and a low matrix effect of less than 8.7%. DBS specimens were stable at 37°C for 2 months and at 50°C for 1 week. The ratio of the concentration of linezolid in DBS samples to that in plasma was 1.2 (95% confidence interval [CI], 1.12 to 1.27). Linezolid exposure calculated from concentrations DBS samples and plasma showed good agreement. In conclusion, DBS analysis of linezolid is a promising tool to optimize linezolid treatment in MDR-TB patients. An easy sampling procedure and high sample stability may facilitate TDM, even in underdeveloped countries with limited resources and where conventional plasma sampling is not feasible.

Evaluation of moxifloxacin for the treatment of tuberculosis: 3 years of experience.

Moxifloxacin (MFX) is a powerful second-line anti-tuberculosis (TB) agent, but the optimal dose has not yet been established and long-term safety data are scarce. We retrospectively reviewed the medical charts of TB patients treated at the Tuberculosis Centre Beatrixoord, University Medical Centre Groningen (Haren, the Netherlands) receiving MFX 400 mg once daily as part of their TB treatment between January 1 2006 and January 1 2009. Safety data and drug-drug interactions were evaluated. Efficacy was predicted based on the area under the concentration-time curve up to 24 h post-dosage (AUC(0-24h))/minimal inhibitory concentration (MIC) ratio. 89 patients were treated with a median dose of 6.9 mg · kg(-1) MFX once daily for a median period of 74 days. Discontinuation of therapy occurred in only three patients due to gastrointestinal side-effects and hypersensitivity. Pharmacokinetic analysis showed an AUC(0-24h)/MIC ratio <100 in eight out of 16 patients. A large variation in protein binding affected the unbound AUC(0-24h) considerably. These data show that MFX treatment was well tolerated in 89 patients receiving a dose of 400 mg once daily for a prolonged period. Considering the variability in (un)bound AUC(0-24h)/MIC ratio, therapeutic drug monitoring is recommended in selected patients (i.e. rifampicin co-medication; MIC ≥ 0.25 mg · L(-1)) to assess optimal therapy.

Pharmacokinetics of rifampin and clarithromycin in patients treated for Mycobacterium ulcerans infection.

In a randomized controlled trial in Ghana, treatment of Mycobacterium ulcerans infection with streptomycin (SM)-rifampin (RIF) for 8 weeks was compared with treatment with SM-RIF for 4 weeks followed by treatment with RIF-clarithromycin (CLA) for 4 weeks. The extent of the interaction of RIF and CLA combined on the pharmacokinetics of the two compounds is unknown in this population and was therefore studied in a subset of patients. Patients received CLA at a dose of 7.5 mg/kg of body weight once daily, rounded to the nearest 125 mg. RIF was administered at a dose of 10 mg/kg, rounded to the nearest 150 mg. SM was given at a dose of 15 mg/kg once daily as an intramuscular injection. Plasma samples were drawn at steady state and analyzed by liquid chromatography-tandem mass spectroscopy. Pharmacokinetic parameters were calculated with the MW/Pharm (version 3.60) program. Comedication with CLA resulted in a 60% statistically nonsignificant increase in the area under the plasma concentration-time curve (AUC) for RIF of 25.8 mg x h/liter (interquartile ratio [IQR], 21.7 to 31.5 mg x h/liter), whereas the AUC of RIF was 15.2 mg x h/liter (IQR, 15.0 to 17.5 mg x h/liter) in patients comedicated with SM (P = 0.09). The median AUCs of CLA and 14-hydroxyclarithromycin (14OH-CLA) were 2.9 mg x h/liter (IQR, 1.5 to 3.8 mg x h/liter) and 8.0 mg x h/liter (IQR, 6.7 to 8.6 mg x h/liter), respectively. The median concentration of CLA was above the MIC of M. ulcerans, but that of 14OH-CLA was not. In further clinical studies, a dose of CLA of 7.5 mg/kg twice daily should be used (or with an extended-release formulation, 15 mg/kg should be used) to ensure higher levels of exposure to CLA and an increase in the time above the MIC compared to those achieved with the currently used dose of 7.5 mg/kg once daily.

Intravenous voriconazole after toxic oral administration.

In a male patient with rhinocerebral invasive aspergillosis, prolonged high-dosage oral administration of voriconazole led to hepatotoxicity combined with a severe cutaneous reaction while intravenous administration in the same patient did not. High concentrations in the portal blood precipitate liver enzyme abnormalities, and therefore, oral administration of voriconazole may have a hepatotoxicity profile different from that of intravenous (i.v.) administration. Intravenously administered voriconazole might still be an option after oral-voriconazole-induced toxicity has resolved.

pH adjustment of human blood plasma prior to bioanalytical sample preparation.

pH adjustment in bioanalytical sample preparation concerning ionisable compounds is one of the most common sample treatments. This is often done by mixing an aliquot of the sample with a proper buffer adjusted to the proposed pH. The pH of the resulting mixture however, does not necessarily have to be the same as the pH of the used buffer due to the significant buffer capacity of the sample. Calculation methods from titration technology were adapted and applied to this problem. The acid-base characteristics of human blood plasma and serum samples were determined and used to calculate the pH of buffer-plasma mixtures. Based on these parameters and the characteristics of the used buffers, two alternative methods were described to prepare buffers that lead to the proposed pH when mixed in the right volume ratio with human plasma samples. The resulting pH of several mixtures of different buffers with human blood plasma were in good accordance with the calculated pH. The proposed calculation methods and recommended buffer preparation methods may lead to more robust bioanalytical methods.

New practical algorithm for modelling analyte recovery in bioanalytical reversed phase and mixed-mode solid phase extraction.

Solid phase extraction (SPE) is a widely used method for sample cleanup and sample concentration in bioanalytical sample preparation. A few methods to model the retention behaviour on SPE cartridges have been described previously but they are either not applicable to ionised species or are not suitable when using multiple wash and elution steps with solvents differing in volume, modifier concentration and acidity. Furthermore, these models were not applied to mixed mode SPE sorbents. In order to overcome these limitations a new SPE modelling algorithm was proposed. The retention behaviour was determined directly on the SPE cartridge by connecting the cartridge online with an HPLC system using a simple but suitable device that was developed and described. The results from these online experiments were used to model the elution behaviour using a quadratic retention function combined with an exponentially modified Gaussian peak shape model to predict analyte recovery under different wash and elution conditions. The validity of the proposed algorithm was tested using practical SPE experiments with an aqueous test mixture as well as with spiked human plasma. Different sequential wash and elution steps were performed using solvents differing in volume and composition. The predicted band shape and recoveries in each collected step were in good agreement with the results obtained from practical experiments. The proposed algorithm is very useful for the description of the SPE behaviour of the analytes on the actual used SPE cartridge and can be used in structural and automated SPE method development.

Effective treatment of verapamil intoxication with 4-aminopyridine in the cat.

To study the value of 4-aminopyridine as an antidote to verapamil intoxication, we subjected 12 adult cats to verapamil poisoning by administering doses of 4.0-25.0 mg/kg verapamil by intravenous infusion. Six animals were given 4-aminopyridine 2 X 0.5 mg/kg i.v. after the verapamil infusion was stopped and the other six animals (the control group) were not. Verapamil caused profound cardiovascular depression and also partial neuromuscular block, both of which were completely reversed by 4-aminopyridine within 50 min, in spite of extremely high serum verapamil concentrations (ranging between 3,700 and 13,500 ng/ml). The six animals that received 4-aminopyridine survived the verapamil intoxication, whereas four of the six animals in the control group died. The results suggest that 4-aminopyridine may be useful in the treatment of verapamil intoxication.

Reconsideration of sample pH adjustment in bioanalytical liquid-liquid extraction of ionisable compounds.

Liquid-liquid extraction (LLE) is widely used as a simple and robust sample preparation technique in bioanalytical sample preparation. When extracting ionisable compounds, most bioanalysts adjust the pH of the sample to achieve fully unionized compounds. Usually, a generally accepted rule is applied to adjust the pH of the aqueous phase, known as the pKa+/-2 rule, depending on the acid/base characteristics of the analyte. By taking a closer look at the general equations that describe the extraction behaviour of ionisable compounds, we extended this pH adjustment rule by taking the distribution ratio and the volume of both liquid phases into account. By choosing an extraction pH based on this extended rule, the selectivity of the extraction can be influenced without loss of recovery. As a measure of this selectivity, two equations were proposed to indicate the ability of the extraction system to discriminate between two compounds. Also, milder extraction pH can be used for pH labile analytes. To use this new rule quantitatively, a new calculation method for the determination of the distribution ratio was derived. These calculations were based on normalized recoveries making this method less susceptible to errors in absolute recovery determination. The proposed equations were supported by demonstrating that careful pH adjustment can lead to higher selectivity. The main conclusion was that a closer look at the extraction pH in bioanalytical methods extends the possibilities of obtaining a higher selectivity or the possibilities of extracting pH labile analytes at milder pH conditions without loss of recovery.

Phase I study of the thrombospondin-1-mimetic angiogenesis inhibitor ABT-510 with 5-fluorouracil and leucovorin: a safe combination.

We performed a phase I study with the thrombospondin-1-mimetic angiogenesis inhibitor ABT-510 combined with 5-fluorouracil and leucovorin (5-FU/LV) to determine safety profile and assess pharmacokinetic interactions. Patients with advanced solid malignancies received LV 20 mg/m(2) followed by 5-FU 425 mg/m(2) both administered intravenously in 15 min daily for 5 days every 4 weeks. ABT-510 was administered subcutaneously twice daily continuously from day 2 onwards. Blood and urine samples for pharmacokinetic analyses were collected at days 1, 5 and 22. Twelve patients received a total of 45 cycles of 5-FU/LV combined with ABT-510. ABT-510 dose levels studied were 50 and 100 mg. The combination was well tolerated, with a toxicity profile comparable to that of 5-FU/LV alone. At the dose levels studied no significant pharmacokinetic interactions were observed. These data indicate that ABT-510 administered twice daily subcutaneously can be safely combined with 5-FU/LV administered daily for 5 days, every 4 weeks.

Comparison of urine and oral fluid as matrices for screening of thirty-three benzodiazepines and benzodiazepine-like substances using immunoassay and LC-MS(-MS).

Benzodiazepines are the most frequently detected medicinal drugs in drivers. The use of benzodiazepines is associated with an increased road accident risk. In this study, the presence of benzodiazepines detected by liquid chromatography-(tandem) mass spectrometry [LC-MS(-MS)] in oral fluid and urine samples obtained from drivers stopped during a roadside survey was compared. In addition, the sensitivity and selectivity of enzyme multiplied immunoassay technique (EMIT II Plus) relative to LC-MS(-MS) was determined for both matrices. A total number of 1,011 urine samples were collected and screened for benzodiazepines using immunoassay (IA) (EMIT II Plus; cutoff 300 ng/mL). In the IA-positive (n = 25) and a group of randomly selected negative urine samples (n = 79), the presence or absence of benzodiazepines was confirmed by LC-MS-MS after deglucuronidation. The corresponding oral fluid samples (n = 101, 3 samples omitted), were analyzed by LC-MS(-MS) and IA (EMIT II Plus; cutoff 10 ng/mL). The presence of benzodiazepines was demonstrated by LC-MS-(MS) in all IA-positive urine samples, but in only four corresponding oral fluid samples. Concentrations in oral fluid were, one substance excepted, lower than in urine. The sensitivity and specificity of EMIT II Plus were better by using urine as matrix for screening of benzodiazepines than by using oral fluid. The results show that benzodiazepines are detectable in oral fluid. More research has to be done to determine the pharmacokinetic profile of the different benzodiazepines in oral fluid and to study the relationship between dose, concentration (in oral fluid and blood), and impairment.

Influence of docosahexaenoic acid on cisplatin resistance in a human small cell lung carcinoma cell line.

In a sensitive, human, small cell lung carcinoma cell line (GLC4) and a cisplatin (CP)-resistant subline (GLC4-CP), the effect of co-culturing with docosahexaenoic acid (DCHA) on CP cytotoxicity was studied. Cells were cultured for 4 days, with 32 microM of DCHA added on days 1 and 3. Incorporation of DCHA into the cellular phospholipids was demonstrated by fatty acid analysis. Supplementation with DCHA led to almost a threefold decrease of resistance in GLC4-CP and had no influence on CP cytotoxicity in GLC4. After culturing with DCHA, cellular platinum (Pt); total Pt bound to DNA; and Pt-GG, Pt-AG, G-Pt-G, and Pt-GMP adduct contents increased in both lines, whereas interstrand cross-link formation was elevated only in GLC4-CP. These experiments demonstrate that DCHA reduces CP resistance. Although an effect on cellular membranes resulting in an increased CP uptake apparently was present, this mechanism does not seem to be responsible for resistance modulation. Rather, an effect on nuclear, probably DNA-related, structures is likely and leads to an increased formation of interstrand cross-links in GLC4-CP.

Characterization of a human small cell lung carcinoma cell line with acquired resistance to cis-diamminedichloroplatinum(II) in vitro.

A 6.4-fold cis-diamminedichloroplatinum(II) (CDDP) resistant human small cell lung carcinoma cell line (GLC4-CDDP) was developed to study acquired CDDP resistance in vitro. Compared to the sensitive cell line (GLC4), the GLC4-CDDP showed an increase in doubling time and a decrease in cloning efficiency, cellular size, double minutes per cell, cellular protein, and nuclear protein content. While a complete cross-resistance for tetraplatin and a partial cross-resistance for doxorubicin, melphalan, cadmium chloride, carboplatin, and cis-dichloro-trans-dihydroxo-cis-bis(isoprolylamine)platinum (IV) (resistance factor, respectively,4.0,5.8,2.1,1.5,2.9) was found, no cross-resistance for vincristine was found. In the GLC4-CDDP line in comparison to the GLC4 line, glutathione and total amount of sulfhydryl compounds was significantly increased, while glutathione S-transferase and glutathione reductase was the same. The platinum content in cells and nuclei was lower in the resistant line, but after correction for cellular protein or volume no difference was found. The amount of platinum bound to DNA was significantly lower in the GLC4-CDDP line. After a 1-h incubation with CDDP, the amount of Pt-GG adducts was the same and the amount of interstrand cross-links was reduced in the GLC4-CDDP line as compared to GLC4. In conclusion, in the GLC4-CDDP line the phenotype and genotype are changed and various mechanisms, such as decreased Pt-DNA binding, elevated glutathione, and reduced interstrand cross-links, play a role in the development of the CDDP resistance.

High-dose cyclophosphamide or melphalan with escalating doses of mitoxantrone and autologous bone marrow transplantation for refractory solid tumors.

As the dose-limiting toxicity of mitoxantrone is hematological, the drug is suitable for dose escalation and use in intensive chemotherapy followed by autologous bone marrow rescue. Adult patients with therapy-resistant solid tumors received a regimen of high-dose cyclophosphamide (7 g/m2) and escalating doses of mitoxantrone in dose steps of 30, 45, 60, and 75 mg/m2. Both drugs were given i.v. on 3 consecutive days. Despite the addition of mesnum (3.5 to 7 g/m2), hemorrhagic cystitis occurred on the second day in four of eight patients, irrespective of the mesnum or mitoxantrone dose. Therefore, the cyclophosphamide in the combination regimen was replaced by high-dose melphalan (180 mg/m2). Mucositis was dose limiting at 75 mg/m2 of mitoxantrone. Responses were seen in eight of ten evaluable patients with four complete responses. Three responders received, after the autologous bone marrow transplantation program, radiotherapy or surgery on pretreatment bulky tumor localizations. Five patients still have disease-free survival after 9 to 36 mo. Pharmacokinetic studies of mitoxantrone were performed by high-performance liquid chromatography with UV detection. The plasma disappearance of mitoxantrone fitted into a three-compartment model with a mean t1/2 alpha of 10 min, a mean t1/2 beta of 96 min, and a slow elimination phase of 172 h. The mean distribution volume was 4294 +/- 3836 liters. We conclude that the high-dose cyclophosphamide-mitoxantrone regimen led to unexpected bladder toxicity, but the combination of melphalan (180 mg/m2) and mitoxantrone (60 mg/m2) can probably be given without major extramedullary toxicity. However, more patients should be evaluated at this dose before definite conclusions can be drawn about toxicity.

Phase II study of oral platinum drug JM216 as first-line treatment in patients with small-cell lung cancer.

PURPOSE: This multicenter phase II trial was performed to determine tumor efficacy and tolerance of the oral platinum drug JM216 in patients with small-cell lung cancer (SCLC). PATIENTS AND METHODS: Patients with SCLC limited disease unfit for intensive chemotherapy or those with extensive disease received JM216 120 mg/m(2)/d for 5 consecutive days every 3 weeks. Individual dose escalation to 140 mg/m(2)/d was allowed if toxicity was

Continuous infusion carboplatin on a 21-day schedule: a phase I and pharmacokinetic study.

A phase I study with continuous infusion carboplatin for 21 days every 6 weeks using a venous access port and portable pump was performed over a dose range of 12 to 32 mg/m2/d, with increments of 2 mg/m2/d. Forty-four patients received 107 courses (median, two; range, one to nine). World Health Organization (WHO) grade III/IV leukopenia and thrombocytopenia occurred in one of seven patients at 30 mg/m2/d, and in two of six and four of six patients at 32 mg/m2/d. Cumulative platelet depression was found at dose levels of 28 mg/m2/d or more. Median glomerular filtration rate (GFR) and effective renal plasma flow, monitored by radioisotope clearances at doses greater than or equal to 20 mg/m2/d, decreased 8.2% (P less than .05) and 10.9% (P less than .01) after two courses. There was a relationship (r = .50, P less than .0002) between the percentage of platelet depression and GFR. No other toxicity was observed. Of the 17 patients who were evaluable, one complete response and four partial responses were observed. In addition, six patients had stable disease. Pharmacokinetic analysis of total and ultrafiltrable platinum (UFPt) was performed by atomic absorption spectrophotometry. Steady-state plasma levels for UFPt were reached after 8 hours. These levels could be detected from the 20 mg/m2/d dose. During steady state, carboplatin dose and UFPt plasma levels were not correlated, but steady-state UFPt and GFR (r = -.27, P less than .05) were. Twenty-four percent of total platinum (Pt) was present as UFPt during steady state (x = 160 +/- 10 micrograms/L). Total body clearance of UFPt exceeded GFR 2.2 times. Mean area under the curve (AUC) for UFPt during continuous infusion was 4,921.8 +/- 301.72 mg.min/L. For total Pt, steady-state plasma levels were not reached; total Pt plasma levels increased between day 7 and day 21 (P less than .0001). There was a significant relation between total Pt serum levels day 7, 14, and 21 and the drug dose administered. Immunohistochemical analysis of DNA-bound Pt in leukocytes showed a linear increase from day 7 to day 14 to day 21 (r = .97) between DNA-bound Pt and duration of infusion in individual patients. The maximum-tolerable dose of carboplatin is 30 mg/m2/d for 21 days (total dose 630 mg/m2) and is recommended for phase II studies.

A phase I and pharmacokinetic study with 21-day continuous infusion of epirubicin.

A phase I study with continuous administration of epirubicin for 21 days using a venous access port and a portable pump was performed. The first dose step was 2 mg/m2/d for 21 days. Interval between courses was 3 weeks. Dose increment per step was 1 mg/m2/d. Twenty-two patients entered the study and received a total of 58 courses with a median of two (range, one to nine). Up to 5 mg/m2/d no toxicity (according to World Health Organization [WHO] criteria) occurred. At 6 mg/m2/d (six pts), one patient had leukopenia grade 3. Two others had some hair loss. At 7 mg/m2/d (four patients), all patients developed mucositis (two grade 3). Three patients had bone marrow depression (one grade 3 anemia, one grade 4 leukocytopenia), and one patient developed the hand-foot syndrome. No other toxicity occurred in the patients. One patient obtained a partial response (18 weeks), ten had stable disease (12 to 54 weeks), seven had progressive disease, and four were not evaluable for response. One patient developed cellulitis around the port, responding to antibiotic treatment; one patient developed a vena cava superior syndrome that resolved with urokinase and removal of the access port. No septicemia occurred. Pharmacokinetic studies were performed by high-performance liquid chromatography (HPLC) with fluorometric detection. Plasma steady state was reached after 57 hours. During steady state there was a linear relationship between epirubicin dose administered and epirubicin level in plasma (r = .58, P less than .05), whole blood (r = .75, P less than .005), and in leukocytes (r = .68, P less than .05). The area under the curve in leukocytes was higher with continuous infusion of 6 mg/m2 for 21 days compared with bolus injection of 80 mg/m2. This method of continuous infusion with epirubicin may be a way to increase intracellular drug-uptake as expressed by intracellular area under curve (AUC). We recommend 6 mg/m2/d for 3 weeks for evaluation of antitumor efficacy in phase II studies.