Safety, tolerability and pharmacokinetics of the new long-acting ...

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Journal of Antimicrobial Chemotherapy (1998) 42, 349–361. Introduction. DW-116 ... quinolone DW-116 after single and multiple dosing in healthy subjects.
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Journal of Antimicrobial Chemotherapy (1998) 42, 349–361

Safety, tolerability and pharmacokinetics of the new long-acting quinolone DW-116 after single and multiple dosing in healthy subjects C. Meyerhoffa, C. Dilgera, S. J. Yoonb, Y. H. Chungb, D. K. Leeb, C. W. Leeb, J. M. Ryub, M. S. Choib, G. Pabsta and C. Reha a

LAB Gesellschaft für pharmakologische Untersuchungen mbH & Co., Wegenerstrasse 13, PO Box 1680, 89231 Neu-Ulm, Germany; bDong Wha Pharmaceutical Industry Co., Ltd, 189, Anyang-Dong, Anyang City, Kyonggi-Do, Korea The safety, tolerability and pharmacokinetics of DW-116, a new fluoroquinolone with a broad antibacterial spectrum, were evaluated in healthy male subjects after administration of single oral doses of 100, 200, 300 and 800 mg and after administration of multiple oral doses of 300 or 400 mg, respectively, for 7 days. DW-116 was well tolerated. Gastrointestinal symptoms and skin reactions were noted and considered to be possibly related to DW-116. The geometric means of the maximum plasma concentrations (Cmax) linearly increased with the dose administered from 1.19 mg/L to 8.73 mg/L after single dose administration. At steady state, the geometric mean minimum and maximum plasma concentrations were 2.14 and 5.65 mg/L, respectively, after the multiple 300 mg dose and 2.73 and 8.00 mg/L, respectively, for the multiple 400 mg dose. Tmax varied between 1 and 5 h. The terminal half-life ranged from 11.37 to 24.89 h. The geometric mean renal clearance was approximately 30 mL/min. Approximately 45% of the dose was excreted unchanged in urine within 60 h. There was no clinically relevant deviation from dose proportionality. The changes in steady-state pharmacokinetic parameters when DW-116 was taken before a high-fat breakfast were not clinically relevant. In conclusion, DW-116 was safe in this study, the first administration to human subjects. Its pharmacokinetics indicate that once-daily dosing may be possible.

Introduction DW-116, 1-(5-fluoro-2-pyridyl)-6-fluoro-7-(4-methyl-1piperazinyl)-1,4-dihydro-4-oxoquinoline-3-carboxylic acid hydrochloride, is a new synthetic fluoroquinolone antibiotic agent synthesized by the R&D Center, Dong Wha Pharmaceutical Company in Korea.1 Although its in-vitro activity is weaker than that of many other quinolones, e.g. ciprofloxacin, ofloxacin and sparfloxacin, it has similar or superior in-vivo activity against Gram-positive and Gramnegative bacteria.2,3 Maximum plasma concentrations are higher than those of equal doses of rufloxacin (mice, rats) or ciprofloxacin (rats, dogs). The area under the concentration–time curve extrapolated to infinity (AUC0– ) is 5- to 25-fold that of ciprofloxacin or rufloxacin. A study comparing mice, rats and dogs showed that there was an

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approximately linear relationship between t½ and species’ body weight.2 Based on these findings, it might be expected that, in humans, DW-116 would be a longacting quinolone requiring once-daily administration only. Judging solely by its in-vitro activity, DW-116 seemed unpromising, but its in-vivo effectiveness in different animal models is a result of its pharmacokinetic profile. Preclinical investigations gave promising results, encouraging further clinical development. In this paper, the results of the first DW-116 administration to healthy human subjects as single and multiple doses are presented. The primary objectives were to assess the safety and tolerability of the new drug, to obtain pharmacokinetic data in human subjects after single or multiple doses, and to determine whether giving DW-116 with food affects its steady-state pharmacokinetics.

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349 © 1998 The British Society for Antimicrobial Chemotherapy

49-731-9840-355.

C. Meyerhoff et al.

Materials and methods Subjects Six healthy male subjects, aged 24–41 years (median 26.5 years) and weighing 57.4–85.3 kg (mean 72.3 kg), participated in the single dose study and 24 healthy male subjects, aged 21–41 years (median 32 years) and weighing 62.3–89.6 kg (mean 73.5 kg), in the multiple dose study. Subjects who had taken part in the single dose study were not allowed to participate in the multiple dose study. Before the study, all subjects were given a medical examination comprising history, physical examination and 12lead resting ECG. Subjects had not used any prescription or over-the-counter medication for at least 2 weeks before dosing. Subjects with any EEG abnormality were excluded from participation in the multiple dose study, because some quinolones are known to decrease the convulsion threshold.4 Blood samples were collected for clinical chemistry, anti-HIV and hepatitis B surface antigen testing, and haematology. Urine was collected for urinalysis and drug screening. The laboratory tests included haematology (erythrocyte sedimentation rate and full blood count with differential and platelet count), clinical chemistry (serum sodium, potassium, chloride, calcium, glucose (fasting), urea, creatinine, uric acid, total bilirubin, triglycerides, total cholesterol, HDL- and LDL-cholesterol, AST/GOT, ALT/GPT, gamma-GT, choline esterase, alkaline phosphatase, creatine kinase, LDH), urinalysis (nitrite, pH, leucocytes, erythrocytes, protein, glucose, ketones, urobilinogen, bilirubin, ascorbic acid) and screening of urine for drugs (alcohol, cannabinoids, amphetamines, barbiturates, benzodiazepines, cocaine and opiates).

Single ascending dose study The study was performed in a double-blind, randomized, placebo-controlled, single ascending dose design. The ascending dose design was chosen for safety reasons. In each of the four study periods the same four subjects received DW-116 and the same two subjects placebo. A 100 mg and a 200 mg DW-116 formulation and two corresponding placebo preparations provided by Dong Wha Pharmaceutical Company, Anyang City, Korea, were used in the study. The subjects who received DW-116 received ascending doses in the following order: treatment A, 100 mg DW-116 (1 100 mg); treatment B, 200 mg DW-116 (1 200 mg); treatment C, 300 mg DW-116 (1 100 mg 1 200 mg); treatment D, 800 mg DW-116 (4 200 mg). The subjects receiving placebo were given the same number of placebos matched to the 100 mg or 200 mg DW116 preparation. There was a wash-out phase of 9 days between two consecutive drug administrations. The subjects were confined in the LAB Human Pharmacology Centre from the evening before each drug intake until the collection of the last blood sample in each study period. The subjects were provided with

standardized meals during confinement. The subjects fasted from at least 10 h before until 4 h after each drug administration; mineral water could be consumed ad libitum. Within 2 h before and after drug administration only the water supplied with the drug was permitted. Drug was administered in the morning. Approximately 4 h after drug administration a lunch was served. All other meals were served at usual mealtimes.

Multiple dose study The study was performed in a double-blind, placebocontrolled, randomized study design. In each of the two groups the same nine subjects received DW-116 and the same three subjects placebo. Subjects in the treatment group A(1–7) received 300 mg DW-116 (1 100 mg 1 200 mg) once daily for 7 days, and those in group B(1–7) received 400 mg DW-116 (2 200 mg) once daily for 7 days. The subjects taking placebo were given a corresponding number of matching placebos. Drugs were administered in the morning. There was an interval of 10 days between the end of the first multiple dose study phase and the start of the second group. The subjects were confined in the LAB Human Pharmacology Centre from the evening before the first drug administration until 24 h after the last drug administration. During confinement, the subjects were provided with standardized meals. Before the drug administration on days 1 and 6, the subjects fasted from at least 10 h before until 4 h after each drug administration; mineral water could be consumed ad libitum. Within 2 h before and after drug administration only the water supplied with the drug was permitted. Approximately 4 h after drug administration a lunch was served. On days 2, 3, 4 and 5 the subjects fasted from 2 h before until 2 h after each drug administration. On day 7 subjects were given a high-fat breakfast (15 g sunflower oil for frying bacon and potatoes, 120 g scrambled egg, 100 g roll, 20 g butter, 25 g bacon, 100 g potatoes, 240 g whole milk) 30 min before drug administration. Approximately 4 h after drug administration, a lunch was served. Mineral water could be consumed ad libitum. All other meals were served at usual mealtimes. Alcohol and caffeine consumption was not allowed during the period of confinement. The study preparations were provided by Dong Wha Pharm. Ind. Co. Ltd. as filmcoated tablets. Both studies were performed under the current European GCP guidelines and in accordance with the Declaration of Helsinki (1964), including the last revision (Hong Kong, 1989). Before the studies were initiated, the study protocol and the informed consent form were approved by an Independent Ethics Committee constituted according to FDA regulations.

Safety assessment Blood pressure, heart rate, respiratory rate and oral body temperature were measured before each dosing, 2, 4, 8 h

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Safety, tolerability and pharmacokinetics of DW-116 after dosing and after the last blood sampling in each single dose study period and before and 6 h after each dosing in the multiple dose study. ECGs were recorded before, 4 and 8 h after dosing and after the last blood sampling in each single dose study period and before and 6 h after each dosing in the multiple dose study. Physical and laboratory examinations (clinical chemistry, haematology, urinalysis) were performed before each dosing and after the last blood sampling in each single dose study period and in the afternoon before (physical examination) or immediately before the first dosing (laboratory examination) and on day 4 in the multiple dose study. Within 14 days after the multiple dose study, the subjects were interviewed by a physician, and underwent physical examination, 12-lead resting ECG and laboratory testing (clinical chemistry, haematology, urinalysis). Any adverse events or adverse drug reactions mentioned upon questioning or spontaneously reported by the subjects were recorded. The assessment of whether an adverse event was probably, possibly or remotely related or unrelated to the treatment was done by a physician (C.M.) before the randomization code was broken.

Plasma, urine and saliva samples were analysed for DW-116 by HPLC methods developed and validated by LAB. The assay methods involved liquid–liquid extraction of human plasma, urine or saliva samples with chloroform and chromatographic separation on a C18 column under isocratic conditions and UV detection. The samples were analysed in different sequences. One sequence consisted of subject samples, a standard curve of eight (urine: seven) different concentrations, a blank sample and quality control samples with three different concentrations in duplicate. Analyte concentrations were evaluated using the internal standard method. The standard curves were calculated from the peak height ratio of analyte/internal standard and the nominal DW-116 concentrations using linear regression: y a bx with 1/x weighting. The characteristics of the different assays are given in Table I. Analytes were stable during the whole analytical procedure when stored under the tested conditions as well as after repeated cycles of freeze–thawing.

Pharmacokinetic calculations Without assuming any specific model of pharmacokinetics the following parameters were determined.

Sample collection, work-up and analytical method Blood samples (7 mL) were drawn from a cubital or forearm vein into lithium-heparinized Vacutainers (Becton Dickinson Vacutainer Systems Europe, Meylan, France) via an indwelling plastic catheter or a steel cannula. The blood samples were centrifuged at 1600g and a temperature of 4°C for 10 min. The plasma supernatant was pipetted off into glass tubes. Urine samples were weighed, and a 20 mL sample was stored in plastic tubes. For the collection of saliva samples the subjects were instructed not to swallow for 2–3 min before saliva sampling. They then spat into a plastic container, in which the saliva remained for approximately 10 min before being transferred using a pipette into glass vials. All samples were stored at a temperature below –20°C immediately upon work-up until analysis.

After single dosing and at steady-state (fasting/non-fasting): measured maximal concentration (Cmax), time of observed maximum (tmax), terminal rate constant from log-linear regression ( z), and terminal half-life (t½, i.e. (ln 2)/ z). After single dosing only: area under the concentration– time curve calculated by the linear trapezoidal rule (time 0 to last sample with a quantifiable concentration) (AUCz), and area under the concentration–time curve from time 0 extrapolated to infinity (AUC0– ). After the first dosing in the multiple dose study: area under the concentration–time curve calculated by the linear trapezoidal rule (from time 0 to 24 h) (AUC0–24). The extrapolated part of AUC0– in each case was 20% of the total AUC0– and this parameter therefore was not reported.

Table I. Characteristics of the analytical method for the estimation of DW-116 in plasma, urine or saliva

Calibrated range (mg/L) Defined LLQ (mg/L) cv % bias % Linearity (mean r2 of the standard curves) Inter-assay accuracy (bias %) Inter-assay precision (cv %)

Plasma

Urine

Saliva

0.05–10 0.05 6.9 –7.9 0.99905 2.2–5.1 2.1–3.2

0.1–10 0.1 0.9 –0.6 0.99996 –1.3 to –1.9 1.3–1.4

0.05–10 0.05 3.0 –3.6 0.99955 –4.2 to –1.2 2.3–5.5

LLQ, lower limit of quantification; cv, coefficient of variation.

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C. Meyerhoff et al. At steady-state (fasting and non-fasting): area under the concentration–time curve calculated by the linear trapezoidal rule (time 0 to 24 h, time of next dose) (AUCss), measured minimal concentration during a dosing interval at steady-state (Cmin), time of observed minimal concentration (tmin), mean concentration during steadystate AUCss/24 h (Cmean), peak–trough fluctuation at steady-state (PTF, i.e. (Cmax – Cmin)/Cmean). In order to determine estimates of higher reliability, the data points to be used for derivation of the terminal rate constant z were selected separately for each treatment, depending on the availability of data. The following parameters of urinary excretion were calculated from concentrations in urine: cumulative urinary excretion up to the end time of the last collection interval (single dosing) or during a dosing interval (steady state) (Ae), maximal excretion rate observed (Emax) and renal clearance calculated as Ae/AUC0– or Ae(0–24)/ AUC0–24, respectively (Clr). Since the urine collected during the last collection intervals contained a quantifiable amount of DW-116 in all cases, the total cumulative urinary excretion, Ae, tends to be underestimated. The saliva concentrations of DW-116 were evaluated descriptively. The ratio of saliva concentration/plasma concentration was calculated for each pair of values and for each subject under DW-116 treatment. This was done for each sampling time, where concentrations of DW-116 in saliva and in plasma could be quantified. The ratio was expressed as a percentage and the medians were calculated for each treatment.

Statistical analysis All statistical tests and comparisons were evaluated at the 95% significance level (P 0.05). Statistical tests were applied to the pharmacokinetic parameters AUC, t½ and Ae. Analysis of variance (ANOVA) was performed via general linear models using the GLM procedure of SAS.5,6 The dose- and concentration-dependent parameter AUC was evaluated after dose-correction and logarithmic transformation. Since the terminal rate constant z is derived by log-linear regression, the parameter t½ (ln 2)/ z was also evaluated after logarithmic pretransformation (without dose-correction). The cumulative urinary excretion Ae was compared between treatments after dose-correction on the original untransformed scale. Lack of a relevant deviation from dose proportionality (comparison between dose levels) or bioequivalence (comparison of fasting and nonfasting), respectively was concluded if the 90% confidence interval was fully contained within the (80%, 125%) region that is used for positive assessment of bioequivalence.7

Results Safety and tolerability of DW-116 The drug appeared to be tolerated well at any of the doses applied. Adverse events were rare and mostly of mild to moderate intensity. In the single dose study two subjects experienced diarrhoea after 100 mg of DW-116 and one subject after 200 mg. Transient itchy erythema accompanied by heat sensation occurred in two of four subjects after administration of the single 800 mg dose. In the multiple dose study, three subjects complained of diarrhoea after 300 mg DW-116 and one subject after 400 mg. Additionally, stomach pain was reported by two subjects receiving 300 mg DW-116 and flatulence by one subject receiving 300 or 400 mg DW-116. Gastrointestinal symptoms, heat sensations and transient itchy erythema were considered to be at least possibly related to DW-116. Central nervous system symptoms, i.e. nervousness (one subject), dizziness (one subject), tiredness (two subjects) and headache (four subjects) were considered to be remotely related to DW-116 and were seen only in the multiple dose study. In the placebo group, tiredness, nervousness, diarrhoea and loss of appetite were each reported once. Two subjects taking placebo complained of headache. The heart rate, systolic and diastolic blood pressure, respiratory rate and body temperature showed slight variations from the predose values. These variations, all within the physiological range, were tolerated by the subjects without any problems and can be explained by circadian variations. The repeatedly determined laboratory parameters mostly remained unaffected by DW-116. Most of the changes in individual parameters found in some subjects after administration of DW-116 or placebo were slightly outside the reference ranges without clinical relevance; in addition, some of them had either already been detectable to an extent of no clinical relevance at the initial screening or they could be explained satisfactorily by reasons not related to administration of the drug.

DW-116 in plasma The mean DW-116 plasma concentrations are shown in Figure 1 and the pharmacokinetic parameters are listed in Tables II to IV. Two subjects in the single dose study and six in the multiple dose study received placebo throughout. Since measurements were performed blinded, all samples were analysed; none contained detectable DW-116.

Single dose study For one of the four subjects given DW-116, none of the plasma, urine or saliva samples contained detectable DW116 after the lowest dose (100 mg DW-116; treatment A)

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Safety, tolerability and pharmacokinetics of DW-116

Figure 1. (a) Mean plasma concentration ( S.D.) of DW-116 after single doses of 100 mg ( ), 200 mg ( ), 300 mg ( ) or 800 mg ( ) given to four healthy male subjects (100 mg: means of three subjects). (b) Mean plasma concentration ( S.D.) of DW-116 after multiple doses of 300 mg ( ) or 400 mg ( ) given to nine healthy male subjects od for 7 days. On days 1 and 6, the drug was administered in the fasting state. On day 7, the drug was administered 30 min after a high-fat breakfast.

although for the other treatments, concentrations in this subject were higher than any of the other three receiving DW-116 treatment. For this subject, Cmax, Ae and Emax were recorded as zero; all other descriptive statistical parameters were calculated based only on the results of the three other subjects. Maximal plasma concentrations of DW-116 were observed (tmax) 1–4 h after administration. Although means are based on data of only four subjects, and therefore are of limited reliability, they show a clear dose-proportionality in the geometric means of Cmax with 1.19 mg/L for treatment A (100 mg), 2.45 mg/L

for treatment B (200 mg), 3.57 mg/L for treatment C (300 mg) and 8.73 mg/L for treatment D. After the maximum, the concentration–time curves showed a monophasic decline with a terminal (elimination) half-life of about 15 h. For treatment A, a result for AUC0– was available for only one of the four subjects. This treatment was, therefore, ignored during the ANOVA for AUC0– . AUC0– of DW-116 in plasma thus could be compared between treatments B, C and D only. The dose-corrected geometric mean ratio B/D was 99.6%, with a 90% confidence interval ranging from 94.5% to 104.9%. For

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C. Meyerhoff et al. Table II. Pharmacokinetic parameters after single doses of DW-116. Values are given as geometric means (range in brackets) DW-116 dose (mg) Pharmacokinetic parameter

100 (n 4)

200 (n 4)

300 (n 4)

800 (n 4)

Cmax (mg/L)

1.19 (0.0–1.27) 2.33b (2.00–3.00) 0.037b (0.026–0.059) 18.72b (11.86–26.97) 19.45a (16.44–21.86) 18.539c NA 43.3 (0.0–49.86) 43.3 (0.0–49.86) 2.1 (0.0–3.2) 44.8c NA

2.44 (2.07–3.25) 2.00 (1.00–3.00) 0.046 (0.040–0.536) 14.92 (12.93–17.34) 41.51 (33.39–58.36) 46.41 (35.97–65.07) 45.2 (40.3–57.4) 90.4 (80.5–114.8) 4.5 (3.8–5.8) 32.5 (21.8–44.5)

3.57 (2.72–4.67) 2.50 (1.00–4.00) 0.046 (0.038–0.052) 15.10 (13.28–18.20) 60.04 (50.72–82.10) 67.14 (56.01–89.40) 44.0 (41.7–48.9) 132.1 (125.0–146.6) 5.3 (3.9–6.4) 32.8 (27.3–37.2)

8.73 (7.28–10.69) 2.50 (1.00–4–00) 0.048 (0.044–0.050) 14.53 (13.98–15.94) 175.6 (137.4–231.7) 186.5 (144.9–245.5) 43.1 (37.0–48.9) 345.1 (295.7–391.0) 13.6 (11.8–16.7) 30.8 (26.6–34.0)

tmax (h)a z

t½ (h) AUCz (mg·h/L) AUC0– (mg·h/L) % dose in urine Ae (mg) Emax (mg/h) Clr (mL/min) NA, not applicable. a Arithmetic mean. b n 3. c n 1.

C/D with a ratio of 96.0% the 90% confidence interval also was fully contained within the (80%, 125%) region. It thus could be shown statistically that there is no clinically relevant deviation from dose proportionality for the range of single doses from 200 mg to 800 mg. For t½, also including data of treatment A, mean ratios B/D and C/D were estimated at 102.7% and 103.9%, respectively, although with a confidence interval exceeding the (80%, 125%) range. A somewhat higher t½ was observed for the lowest dose treatment A.

Multiple dose study The results for the different days and the different treatments are given in a composite code: for example, ‘treatment A1’ means ‘treatment A, day 1’ and ‘treatment B6’ means ‘treatment B, day 6’. Maximal plasma concentrations of DW-116 were observed on day 1 (tmax) between 1 and 3 h after administration. The arithmetic means of t½ were estimated as 14.27 h (range 12.16–17.70 h) for treatment A1 and 15.36 h (range 11.37–20.98 h) for treatment B1. The geometric

means of Cmax were 3.85 mg/L for treatment A1 (300 mg) and 5.41 mg/L for treatment B1 (400 mg) and thus increased slightly more from A1 to B1 than might be expected. Trough DW-116 plasma concentrations were similar on days 5, 6 and 7. The 90% confidence interval for the dose-corrected geometric mean ratio A1/B1 of AUC0–24 of DW-116 in plasma on day 1 was fully contained within the (80%, 125%) region required for a conclusion of bioequivalence. On days 6 and 7, however, the confidence intervals for AUCss marginally exceeded the acceptance range. Regarding the cumulative urinary excretion of DW-116, the dose-corrected geometric mean ratios A/B of Ae on days 1, 6 and 7 were fully contained with their 90% confidence intervals in the (80%, 125%) acceptance region. The same applies for t½ in plasma. Under steady-state fasting conditions, maximal plasma concentrations of DW-116 were observed (tmax) between 1 and 4 h after administration. The geometric means of Cmax were 5.65 mg/L for treatment A6 (300 mg) and 8.00 mg/L for treatment B6 (400 mg) and thus are in a reasonably good agreement with an assumed dose proportionality. The plasma concentrations decreased with calculated

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Safety, tolerability and pharmacokinetics of DW-116 Table III. Pharmacokinetic parameters after multiple doses of 300 mg DW-116 od for 7 days; values are given as geometric means (range in brackets) Pharmacokinetic parameters

Day 1 (fasting) (n 9)

Day 6 (fasting) (n 9)

Day 7 (non-fasting) (n 9)

Cmax (mg/L)

5.65 (5.04–6.21) 2.33 (1.00–4.00) 0.040 (0.034–0.047) 17.54 (14.69–20.33) NA

5.47 (4.48–6.93) 2.89 (1.00–5.00) 0.038 (0.032–0.043) 18.34 (16.02–21.91) NA

AUCSS (mg·h/L)

3.85 (3.42–4.17) 1.56 (1.00–3.00) 0.049 (0.039–0.057) 14.16 (12.16–17.7) 50.4 (40.7–59.5) NA

Cmin (mg/L)

NA

Cmean

NA

PTF (%)

NA

% dose in urine

34.8 (27.5–44.7) 104.4 (82.6–134.2) 6.6 (5.4–10.0) 34.5 (27.1–48.8)

87.7 (76.3–109.4) 2.14 (1.81–2.84) 3.65 (3.18–4.56) 95.5 (73.9–124.4) 49.4 (36.6–60.5) 148.2 (109.7–181.4) 8.5 (5.9–11.5) 28.2 (21.3–37.5)

82.2 (65.9–96.5) 2.10 (1.65–2.81) 3.42 (2.74–4.02) 97.6 (77.8–120.1) 53.4 (41.2–70.3) 160.2 (123.6–211.0) 10.0 (6.9–15.4) 32.5 (25.2–46.6)

tmax (h)a z

t½ (h) AUC0–24 (mg·h/L)

Ae (mg) Emax (mg/h) Clr (mL/min) NA, not applicable. Arithmetic mean.

a

geometric means of t½ about 14–18 h. Minimal steady-state concentrations were 2.14 and 2.73 mg/L and the geometric mean peak–trough fluctuation was estimated as between 96% and 109% for both treatments.

DW-116 in urine The mean urinary concentrations of DW-116 are shown in Figure 2. The pharmacokinetic parameters of DW-116 are presented in Tables II to IV.

Single dose study The assessment of urinary recovery is limited by the restricted duration of urine collection. Although the renal clearance tends to be underestimated, results are consistent between treatments with geometric means of about 32 mL/min. As to the cumulative urinary excretion, treatments B, C and D were found to be very similar. The

dose-corrected arithmetic mean for treatment B was just 5.22% higher than that for D and the dose-corrected mean for C exceeded the mean for D by 1.69%. The dosecorrected mean for treatment A was 25% lower based on an estimate including a zero result for the subject without detectable DW-116. If this result were disregarded, a mean ratio close to 100% would result, i.e. not indicating any deviation from dose proportionality.

Multiple dose study The assessment of urinary recovery on day 1 again was limited by the restricted duration of urine collection. Within 24 h after the first dosing, 35% (treatment A1) and 33% (treatment B1) of the dose, respectively, was recovered in the urine. These data correspond to an average (geometric mean) renal clearance during the first 24 h after dosing of 34.5 and 31.4 mL/min. After fasting administration at steady-state, within a 24 h dosing

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C. Meyerhoff et al. Table IV. Pharmacokinetic parameters after multiple doses of 400 mg DW-116 od for 7 days; values are given as geometric means (range in brackets) Pharmacokinetic parameters

Day 1 (fasting) (n 9)

Day 6 (fasting) (n 9)

Day 7 (non-fasting) (n 9)

Cmax (mg/L)

8.00 (5.69–14.55) 1.56 (1.00–3.00) 0.041 (0.032–0.055) 16.74 (12.72–22.02) NA

7.36 (5.36–12.91) 2.33 (1.00–4.00) 0.040 (0.028–0.055) 17.15 (12.68–24.89) NA

AUCSS (mg·h/L)

5.41 (4.74–7.32) 1.89 (1.00–3.00) 0.046 (0.033–0.061) 15.09 (11.37–20.98) 69.7 (57.9–95.7) NA

Cmin (mg/L)

NA

Cmean

NA

PTF (%)

NA

% dose in urine

32.9 (25.5–37.6) 131.5 (101.9–150.3) 8.8 (7.0–10.4) 31.4 (17.7–39.4)

114.8 (80.4–222.7) 2.73 (1.74–6.16) 4.78 (3.35–4.15) 109.2 (83.5–131.1) 45.3 (25.7–55.6) 181.0 (102.9–222.6) 12.2 (9.8–15.0) 26.3 (7.7–44.8)

107.4 (78.3–202.9) 2.60 (1.65–5.15) 4.48 (3.26–8.46) 104.2 (72.7–146.4) 48.2 (39.1–55.0) 192.9 (156.3–220.2) 11.6 (9.1–14.8) 29.9 (15.0–43.34)

tmax (h)a z

t½ (h) AUC0–24 (mg·h/L)

Ae (mg) Emax (mg/h) Clr (mL/min) NA, not applicable. Arithmetic mean.

a

interval 50% and 46% of the dose, respectively, was recovered in the urine. These data correspond to a geometric mean renal clearance at steady-state of 28.2 and 26.3 mL/min for treatments A6 and B6, respectively. When given with food, 54% and 48% of the dose, respectively, were recovered within 24 h after dosing. These data correspond to a geometric mean renal clearance at steady-state of 32.5 and 29.9 mL/min for treatments A7 and B7, respectively. The absolute DW-116 concentrations in urine were at least 12 mg/L from day 1 until 48 h after the last dosing. From day 6 to day 7, the urine concentrations were 20 mg/L with only two exceptions (subject no. 3/treatment A6: 16.92 mg/L and subject no. 17/treatment B7: 19.43 mg/L).

DW-116 in saliva The median ratio of saliva concentration of DW-116 to plasma concentration of DW-116 is given in Figure 3.

Single dose study Saliva concentration profiles were similar to those in plasma; they showed a higher variability and maximal concentrations for treatment D ranged from 4 to 7.5 mg/L. The median ratio of the saliva concentration to plasma concentration was relatively constant between 45% and 55% during the terminal elimination phase.

Multiple dose study Saliva concentration profiles again were similar to those in plasma, but showed a higher variability. Differences between single dose and steady-state conditions, however, were not as pronounced as for plasma. The median ratio of the saliva concentration to plasma concentration was higher shortly after drug administration than later on.

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Figure 2. (a) Mean urinary concentration ( S.D.) of DW-116 after single doses of 100 mg ( ), 200 mg ( ), 300 mg ( ) or 800 mg ( ) given to four healthy male subjects (100 mg: means of three subjects). (b) Mean urinary concentration (S.D.) of DW-116 after multiple doses of 300 mg given to nine healthy male subjects od for 7 days. On days 1 ( ) and 6 ( ), the drug was administered in the fasting state. On day 7 ( ), the drug was administered 30 min after a high-fat breakfast. (c) Mean urinary concentration ( S.D.) of DW-116 after multiple doses of 400 mg given to nine healthy male subjects od for 7 days. On days 1 ( ) and 6 ( ), the drug was administered in the fasting state. On day 7 ( ), the drug was administered 30 min after a high-fat breakfast.

Food effect When a drug is given together with food, a delay in absorption often occurs. With DW-116, maximal plasma concentrations of DW-116 were attained slightly later when DW-116 was taken with food: means of 2.33 h or 1.56 h without food (treatment A6 or B6, respectively) compared with 2.89 h or 2.33 h, respectively, with food. The geometric means of Cmax were 5.47 mg/L for treatment

A7 and 7.36 mg/L for treatment B7, slightly lower than the values obtained when the drug was taken on an empty stomach. Means indicate dose-proportionality. The minimal and average steady-state concentrations were marginally lower than those in the fasting state. The evaluation with respect to food effects, i.e. comparing AUCss results on day 7 (non-fasting) with results on day 6 (fasting) led to mean ratios A7/A6 and B7/B6 of 93.7% and 93.6%,

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Figure 3. (a) Median ratio of salivary to plasma concentration of DW-116 after single doses of 100 mg ( ), 200 mg ( ), 300 mg ( ) or 800 mg ( ) given to four healthy male subjects (100 mg: median of three subjects). (b) Median ratio of salivary to plasma concentration of DW-116 after multiple doses of 300 mg given to nine healthy male subjects od for 7 days. On days 1 ( ) and 6 ( ), the drug was administered in the fasting state. On day 7 ( ), the drug was administered 30 min after a high-fat breakfast. (c) Median ratio of salivary to plasma concentration of DW-116 after multiple doses of 400 mg given to nine healthy male subjects od for 7 days. On days 1 ( ) and 6 ( ), the drug was administered in the fasting state. On day 7 ( ), the drug was administered 30 min after a highfat breakfast.

respectively. Confidence intervals were fully contained within the (80%, 125%) range. The same applies for the comparison of the cumulative urinary excretion between days 7 and 6, although urinary excretion was marginally higher when the drug was administered with food.

Discussion Overall, DW-116 was well tolerated. The frequency of adverse drug reactions was low after single doses up to 300 mg and multiple doses of 300 or 400 mg, for 7 days.

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Safety, tolerability and pharmacokinetics of DW-116 Table V. Results of statistical comparisons Single doses Parameter

100 mg/800 mg

200 mg/800 mg

300 mg/800 mg

AUC0–

ND



126.8% (97.1%, 165.6%) 75.2% (36.4%, 114.1%)

99.6% (94.5%, 104.9%) 102.7% (80.7%, 130.8%) 105.2% (66.3%, 144.1%)

96.0% (91.1%, 101.1%) 103.9% (81.6%, 132.3%) 101.7% (62.8%, 140.6%)

Ae

Multiple doses of 300 mg/400 mg

AUC t½ Ae

AUC Ae

day 1

day 6 (fasted)

day 7 (fed)

96.4% (85.7%, 108.3%) 93.8% (81.6%, 108.0%) 106.1% (94.8%, 117.5%)

101.8% (82.1%, 126.4%) 104.8% (93.6%, 117.3%) 108.3% (93.4%, 123.3%)

102.0% (82.9%, 125.6%) 106.9% (92.8%, 123.2%) 111.2% (99.6%, 122.8%)

300 mg fed/fasted

400 mg fed/fasted

93.7% (90.9%, 96.6%) 107.8% (102.4%, 113.1%)

93.6% (91.7%, 95.6%) 105.0% (96.8%, 113.2%)

The respective treatments were compared for equivalence. For comparisons between different doses, a linear dose correction was applied to the dose-related pharmacokinetic parameters AUC and Ae. The respective ratios for the original (comparison of fed and fasted) or dose-corrected parameters are given with 90% confidence interval (lower limit, upper limit). ND, not done.

Surprisingly, there were fewer adverse events after 400 mg DW-116 od for 7 days than after 300 mg. The adverse event profile of DW-116 was comparable to that of other quinolones, when applied for the first time to human subjects8 or during preregistration clinical trials.9 After a single dose of 800 mg, two subjects developed an itchy erythema, starting approximately 30 min after drug intake and lasting for approximately 2 h, coinciding with tmax. These two subjects, however, did not exhibit the highest plasma concentrations of DW-116 (7.61 or 9.79 mg/L, respectively): In the second group of the multiple dose study, on days 6 or 7, three subjects had a Cmax 9 mg/L. Under the multiple dosing scheme the rate of drug plasma concentration change is lower. The occurrence of itchy erythema may have been related to a steep increase in plasma concentrations occurring after single doses of 800 mg. The frequency of skin reactions described after administration of marketed quinolones varies between 1% and 4%.10 It is unlikely that our observation was related to phototoxicity, which is known to occur most commonly after lomefloxacin adminis-

tration,10 because the subjects were confined, and not subjected to UV radiation, when the drug was administered. There are hints from animal experiments that fluoroquinolones cause a concentration-dependent release of histamine from mast cells. 11 This might explain the rash which occurred after 800 mg of DW-116 as single dose, so single doses of 800 mg DW-116 should be used with caution in future studies. Its tmax (occurring between 1 and 5 h) shows that DW116 is absorbed slightly more slowly than ciprofloxacin, ofloxacin, norfloxacin or fleroxacin, which have tmax values between 0.5 and 2 h. However, higher peak plasma concentrations are reached than after equal doses of ciprofloxacin or norfloxacin. The terminal half-life of DW116, approximately 15 h in the single dose study and up to 18 h in the multiple dose study, is comparable to that of sparfloxacin, longer than that of newer long-acting gyrase inhibitors, such as fleroxacin (t½ 12 h) and trovafloxacin (t½ 10 h) and pronouncedly longer than that of ciprofloxacin, norfloxacin or ofloxacin (t½ 6–8 h8,10,12,13). DW-116 has a comparatively low renal clearance. The

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C. Meyerhoff et al. renal clearance of ciprofloxacin is approximately 10 times higher (300–400 mL/min) and that of ofloxacin five to six times higher ( 180 mL/min12,14). The clearance of DW116 is in the order of that of other long-acting gyrase inhibitors, slightly higher than that of rufloxacin, sparfloxacin and trovafloxacin and lower than that of fleroxacin.8,12,14 Concentrations of DW-116 in urine for at least 48 h after the last dose by far exceeded the range of MICs against Gram-positive and Gram-negative bacteria reported by Lee 2 and were above the MIC against clinical isolates with the exception of Pseudomonas aeruginosa and quinolone-resistant Staphlyococcus aureus.3 The amount of DW-116 excreted in urine, range 25.5–70.3%, is higher than that of sparfloxacin (10–15% excreted) and comparable to that of norfloxacin (20–40%), rufloxacin (30–50%), ciprofloxacin (61.5%) and fleroxacin (61.5%).12 It is hypothesized that gyrase inhibitors undergo glomerular filtration and tubular secretion.12 If this applies to DW-116 as well, DW-116 belongs to the subgroup of gyrase inhibitors, which undergo significant reabsorption, thus contributing to the long terminal half-life. The pharmacokinetic data presented here were obtained using comparatively small groups of subjects. Since there was no detectable DW-116 in samples from one subject after the first single dose of 100 mg, the pharmacokinetic data for a single dose of 100 mg DW-116 are based on three subjects only. Whatever the reason for these zero concentrations (e.g. subject’s non-compliance), the true mean concentration–time profile for treatment A in consequence might have been underestimated, because undetectable concentrations were recorded as zeroes during the calculations. However, it is mandatory that the first administration of a new drug to humans is performed in small groups for safety reasons. The validity of these small-group studies is supported by the pharmacokinetic consistency with animal data available so far.2 Larger groups of human subjects will be used in future studies. Nevertheless, there was no hint for clinically relevant deviation from dose-proportionality between single doses of 200–800 mg and between daily doses of 300 or 400 mg when given for 7 days, although for AUCSS the 90% confidence interval marginally exceeded the (80%, 125%) bioequivalence region. However, it should be taken into account that this aspect was evaluated by comparing parallel groups such that somewhat larger confidence intervals could be expected. Trough plasma concentrations indicated that steadystate was reached at day 5. The theoretical prediction for the ratio of AUCSS to AUC0–24 of day 1 calculated from 1/(1 – e – z ), where z ln 2/t½ and is the dosing interval, is about 1.49–1.66 for a t½ of 15–18 h. The results were close to the theoretical prediction, thus emphasizing that the pharmacokinetics of DW-116 do not change when the drug is given in a multiple dose schedule. The ratio of the geometric means of AUCSS to AUC0–24 was 1.74 or 1.64

for the 300 mg dose group on day 6 or 7, respectively, and 1.65 or 1.54 for the 400 mg dose group on day 6 or 7. Within the group of gyrase inhibitors, the effect on absorption of being taken with food varies considerably. The gyrase inhibitors most prone to such effects are ciprofloxacin and norfloxacin, although the published data on ciprofloxacin are contradictory.13,14 Sörgel & Kinzig14 suggested that N4 -methylation protects against food effects; our findings do not contradict this, as we did not observe a clinically relevant effect of food on the pharmacokinetics of DW-116 (which is N4 -methylated). The saliva concentration gives some insight into the distributional behaviour and may serve as a rough estimate for the free (not protein-bound) arterial concentration of gyrase inhibitors.15 Our results show that DW116 quickly appears in saliva. The saliva concentrations amount to somewhat less than 50% of the corresponding plasma concentrations, leading to the conclusion that somewhat more than 50% of DW-116 is protein-bound. Future protein binding studies will be performed to confirm this finding. In conclusion, DW-116 was safe upon first administration to humans. Its pharmacokinetics indicate that once-daily dosing of 100–400 mg may be suitable for various indications, e.g. systemic, respiratory or urinary tract infections. The results of study encourage further clinical development of this new drug.

References 1. Yoon, S. J., Chung, Y. H., Lee, C. W., Oh, Y. S., Choi, D. R. & Kim, N. D. (1996). Novel quinolone carboxylic acid derivatives. USA Patent No. 5496947-A.6. 2. Lee, D. K. (1995). Pharmacokinetic study of a new quinolone, DW-116. Drugs 49, Suppl. 2, 323–5. 3. Choi, K. H., Hong, J. S., Kim, S. K., Lee, D. K., Yoon, S. J. & Choi, E. C. (1997). In-vitro and in-vivo activities of DW-116, a new fluoroquinolone. Journal of Antimicrobial Chemotherapy 39, 509–14. 4. Enginar, N. & Eroglu, L. (1991). The effect of ofloxacin and ciprofloxacin on pentylenetetrazol-induced convulsions in mice. Pharmacology, Biochemistry and Behavior 39, 587–9. 5. SAS Institute Inc. (1990a). SAS/STAT User’s Guide, Version 6, 4th edn. SASInstitute Inc., Cary, NC. 6. SAS Institute Inc. (1990b). SAS Procedures Guide, Version 6, 3rd edn. SAS Institute Inc., Cary, NC. 7. CPMP Working Party on Efficacy of Medicinal Products. (1991). Note for guidance III/54/89-EN: investigation of bioavailability and bioequivalence. In Arzneimittelprüfrichtlinien, 2nd supplement, 1992 (Feiden, F., Ed.), pp. 2.66/1–12. Wissenschaftliche Verlagsgesellschaft mbH, Stuttgart. 8. Teng, R., Harris, S. C., Nix, D. E., Schentag, J. J., Foulds, G. & Liston, T. E. (1995). Pharmacokinetics and safety of trovafloxacin (CP-99,219), a new quinolone antibiotic, following administration of single oral doses to healthy male volunteers. Journal of Antimicrobial Chemotherapy 36, 385–94.

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Safety, tolerability and pharmacokinetics of DW-116 9. Geddes, A. M. (1993). Safety of fleroxacin in clinical trials. American Journal of Medicine 94, Suppl. 3A, S201–3. 10. McEnvoy, G. K. (1996). AHFS Drug Information 96. American Society of Health System, Bethesda, MD. 11. Yoshida, M., Takayama, S. & Kato, M. (1994). Effect of levofloxacin and ciprofloxacin injection on permeability of the tail vein in mice and skin microvasculature in rats. International Journal of Tissue Reactions 16, 105–12. 12. Sörgel, F. & Kinzig, M. (1993b). Pharmacokinetics of gyrase inhibitors, part 2: Renal and hepatic elimination pathways and drug interaction. American Journal of Medicine 94, Suppl. 3A, S56–69.

13. Frost, R. W., Carlson, J. D., Dietz, A. J., Heyd, A. & Lettieri, J. T. (1989). Ciprofloxacin pharmacokinetics after a standard or highfat/high-calcium breakfast. Journal of Clinical Pharmacology 29, 953–5. 14. Sörgel, F. & Kinzig, M. (1993a). Pharmacokinetics of gyrase inhibitors, part 1: Basic chemistry and gastrointestinal disposition. American Journal of Medicine 94, Suppl. 3A, S44–55. 15. Schaefer, H. G., Ahr, G. & Kuhlmann, J. (1996). Pharmacokinetic development of quinolone antibiotics. International Journal of Clinical Pharmacology and Therapeutics 33, 266–76. Received 16 April 1997; returned 25 June 1997; revised 18 November 1997; accepted 15 March 1998

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