Human Abuse Potential of Oral NKTR-181 in Recreational Opioid Users: A Randomized, Double-Blind, Crossover Study.

OBJECTIVE: To evaluate the human abuse potential, pharmacokinetics, pharmacodynamics, and safety of oral NKTR-181 (oxycodegol), a novel full mu-opioid receptor agonist, relative to oral oxycodone. DESIGN: This double-blind, randomized, single-dose, crossover human abuse potential study was conducted in healthy, adult, non-physically dependent recreational opioid users. SETTING: Inpatient clinical research site. SUBJECTS: Seventy-one subjects randomized (95.7% male, 65.2% African American, mean age = 31.7 years). METHODS: The primary objective was to compare two therapeutic doses of NKTR-181 (400 and 600 mg) with 40 and 60 mg of oxycodone and a supratherapeutic dose (1200 mg) of NKTR-181 with 60 mg of oxycodone using visual analog scale (VAS) ratings for Drug Liking "at this moment" (Drug Liking). Secondary objectives included VAS ratings for other subjective measures, and central nervous system (CNS) mu-opioid effects were assessed using pupillometry. Each subject received single oral doses of five treatments and matching placebo. RESULTS: Compared with 40 and 60 mg of oxycodone, the maximum mean Drug Liking score at 400 and 600 mg NKTR-181 was significantly lower, and the rate of onset and extent of Drug Liking for all NKTR-181 doses in the first two hours postdose were also significantly lower. Delayed attenuated Drug Liking and pupillary miosis response following administration of NKTR-181 vs oxycodone were consistent with slower NKTR-181 CNS entry kinetics and mu-opioid receptor binding. No adverse events were rated as severe, and somnolence and dizziness occurred more frequently when subjects received oxycodone. CONCLUSIONS: NKTR-181 at oral doses of 400 and 600 mg showed significantly fewer and less severe subjective effects accepted as representative of opioid abuse potential, such as lower peak Drug Liking in recreational opioid users, than 40 and 60 mg of oxycodone.

Human Abuse Potential of the New Opioid Analgesic Molecule NKTR-181 Compared with Oxycodone.

Objective: Evaluate the human abuse potential, pharmacokinetics, pharmacodynamics, and safety of NKTR-181, a novel mu-opioid agonist molecule, relative to oxycodone. Design: This randomized, single-center, double-blind, active- and placebo-controlled five-period crossover study enrolled healthy, adult, non-physically dependent recreational opioid users. Setting: Inpatient clinical research site. Subjects: Forty-two randomized subjects (73.8% male, 81% white, mean age = 25 years). Methods: The primary objective was to evaluate single orally administered 100, 200, and 400 mg NKTR-181 doses in solution compared with 40 mg oxycodone and placebo solutions using the Drug Liking visual analog scale. Secondary measures included the Drug Effects Questionnaire, Addiction Research Center Inventory/Morphine Benzedrine Group Subscale, Price Value Assessment Questionnaire, Global Assessment of Overall Drug Liking, and Take Drug Again Assessment. Central nervous system mu-opioid effects were assessed using pupillometry. The study included qualifying and treatment phases. Subjects received each of the five treatments using a crossover design. Results: NKTR-181 at all dose levels had significantly lower Drug Liking Emax than oxycodone (P < 0.0001). Drug Liking scores for oxycodone increased rapidly within 15 minutes and peaked at approximately one hour postdose, whereas Drug Liking (and most secondary abuse potential measures) for all doses of NKTR-181 were comparable with placebo for at least the first hour. Only the 400 mg Drug Liking scores were minimally differentiated vs placebo from one and a half to four hours, but remained significantly lower than oxycodone (P < 0.003). NKTR-181 treatment-related adverse effects were mild and occurred at a lower rate compared with oxycodone. Conclusions: NKTR-181 demonstrated delayed onset of CNS effects and significantly lower abuse potential scores compared with oxycodone in recreational opioid users.

NKTR-102 Efficacy versus irinotecan in a mouse model of brain metastases of breast cancer.

BACKGROUND: Brain metastases are an increasing problem in women with invasive breast cancer. Strategies designed to treat brain metastases of breast cancer, particularly chemotherapeutics such as irinotecan, demonstrate limited efficacy. Conventional irinotecan distributes poorly to brain metastases; therefore, NKTR-102, a PEGylated irinotecan conjugate should enhance irinotecan and its active metabolite SN38 exposure in brain metastases leading to brain tumor cytotoxicity. METHODS: Female nude mice were intracranially or intracardially implanted with human brain seeking breast cancer cells (MDA-MB-231Br) and dosed with irinotecan or NKTR-102 to determine plasma and tumor pharmacokinetics of irinotecan and SN38. Tumor burden and survival were evaluated in mice treated with vehicle, irinotecan (50 mg/kg), or NKTR-102 low and high doses (10 mg/kg, 50 mg/kg respectively). RESULTS: NKTR-102 penetrates the blood-tumor barrier and distributes to brain metastases. NKTR-102 increased and prolonged SN38 exposure (>20 ng/g for 168 h) versus conventional irinotecan (>1 ng/g for 4 h). Treatment with NKTR-102 extended survival time (from 35 days to 74 days) and increased overall survival for NKTR-102 low dose (30 % mice) and NKTR-102 high dose (50 % mice). Tumor burden decreased (37 % with 10 mg/kg NKTR-102 and 96 % with 50 mg/kg) and lesion sizes decreased (33 % with 10 mg/kg NKTR-102 and 83 % with 50 mg/kg NKTR-102) compared to conventional irinotecan treated animals. CONCLUSIONS: Elevated and prolonged tumor SN38 exposure after NKTR-102 administration appears responsible for increased survival in this model of breast cancer brain metastasis. Further, SN38 concentrations observed in this study are clinically achieved with 145 mg/m(2) NKTR-102, such as those used in the BEACON trial, underlining translational relevance of these results.

Comparative bioavailability of inhaled treprostinil administered as LIQ861 and Tyvaso® in healthy subjects.

INTRODUCTION: Treprostinil is a synthetic prostacyclin analogue approved for inhalation administration to patients with pulmonary arterial hypertension (PAH) via nebulized Tyvaso® inhalation solution. LIQ861 is an inhaled, dry-powder formulation of treprostinil produced using Print® (Particle Replication in Nonwetting Templates) technology, a proprietary process for designing and producing highly uniform drug particles. METHODS: We conducted comparative bioavailability analyses of treprostinil exposure from LIQ861 (79.5 µg capsule [approximate delivered dose of 58.1 µg treprostinil]) compared with Tyvaso® (9 breaths [approximate delivered dose of 54 µg treprostinil]). RESULTS: Treprostinil exposure parameters had least squares geometric mean ratios (LIQ861: Tyvaso®) between 0.9 and 1.0 with 90% confidence intervals contained within 0.8 to 1.25. LIQ861 and Tyvaso® were both well tolerated. DISCUSSION: Results showed comparable bioavailability of treprostinil and similar tolerability for LIQ861 and Tyvaso® administered to healthy adults. CONCLUSIONS: Given the comparable treprostinil bioavailability and similar safety profiles of LIQ861 and Tyvaso®, LIQ861 fulfills a significant unmet need for PAH patients by maximizing the therapeutic benefits of treprostinil by safely delivering doses to the lungs in 1 to 2 breaths using a discreet, convenient, easy-to-use inhaler.

Safety, Tolerability, and Pharmacokinetics of RT234 (Vardenafil Inhalation Powder): A First-in-Human, Ascending Single- and Multiple-Dose Study in Healthy Subjects.

Background: RT234 (vardenafil inhalation powder) is being developed for pulmonary administration "as needed", to acutely improve exercise tolerance and symptoms in patients with pulmonary arterial hypertension (PAH). Methods: This single-center, open-label, randomized study in 32 healthy adult subjects evaluated single and multiple inhalation doses of RT234, for safety, tolerability, and pharmacokinetics (PKs). Results: RT234 was generally safe and well tolerated at single doses of 0.2-2.4 mg and after repeated dose administration of up to 2.4 mg q4h for four doses daily for 9 days. The most common treatment-emergent adverse events were mild-to-moderate headaches. There was no evidence of pulmonary irritation or inflammation. Vardenafil was absorbed very rapidly after inhalation as RT234, independent of dose level and number of doses administered. The tmax occurred at the time that the first blood sample following completion of dosing. After Cmax was achieved, plasma vardenafil concentrations declined rapidly in an exponential fashion that appeared to be parallel among dose levels. Vardenafil plasma concentrations and PK parameters increased in a dose-proportional manner. Vardenafil systemic exposure was notably greater after oral administration of 20 mg vardenafil tablets (Levitra®) than after administration of any dose level of RT234. During repeated dose administration of RT234, Cmax was attained rapidly following each dose and in a pattern similar to that observed after single-dose administration. Minor accumulation, characterized by very low mean morning predose vardenafil concentrations (<0.5 ng/mL), occurred after q4h dosing of up to four doses per day for 9 days. Taken together, these findings show that no clinically important vardenafil accumulation is likely after repeated-dose administration of RT234. Mean vardenafil t1/2 values were comparable after single- and repeated-dose administration. Conclusions: Comparative plasma vardenafil bioavailability data from this study provide scientific justification for reliance on Food and Drug Administration findings for Levitra tablets. These findings support further evaluation of RT234 for as-needed treatment of patients with PAH. The Clinical Trials Registration number is ACTRN12618001077257.

Integrated population pharmacokinetics of etirinotecan pegol and its four metabolites in cancer patients with solid tumors.

PURPOSE: Etirinotecan pegol (EP), a long-acting topoisomerase-1 inhibitor, is a polyethylene glycol conjugate of irinotecan, with an intended indication for treatment of breast cancer with brain metastases. The objective of this study was to develop a population pharmacokinetic (popPK) model of EP and four of its metabolites (irinotecan, SN38, SN38-glucuronide, and APC) and determine covariates affecting their pharmacokinetics. METHODS: Data from 83 cancer patients enrolled in phase 1 studies were used. The model was developed in two stages: (1) concentration-time data were analyzed with a 3-analyte model for EP, irinotecan, and SN38; and (2) a 5-analyte model developed based on expansion of 3-analyte model to include concentration-time data for SN38 glucuronide and APC with parameter values from 3-analyte model fixed. Covariate relationships with parameters were selected based on Wald's test within the Wald's Approximation Method approach, first for the 3-analyte model then the 5-analyte model. RESULTS: The final integrated popPK model for the five analytes was a two-compartment per analyte model that followed the metabolic cascade of EP to irinotecan, followed by metabolism of irinotecan to the previously known metabolites, but with altered exposures as compared to administration of irinotecan. With the model developed based on total dose of EP, the population estimates of EP clearance and central volume were 0.237 L/h and 5.5 L, respectively. Patient age, body surface area (BSA), and estimated glomerular filtration rate were found to correlate with EP clearance and BSA with EP central volume. Individuals who were homozygous for UGT1A1*28 genotype had modestly reduced elimination capacity of SN38 compared to heterozygous and wild-type genotypes. Simulations evaluating the clinical importance of significant covariates indicated minimal change in areas under the curve and peak concentrations of EP and SN38. CONCLUSIONS: The pharmacokinetics of EP and four metabolites including the active metabolite SN38 were described by an integrated popPK model. Other than BSA, which was already accounted by a BSA-based dosing scheme, no other covariates were deemed to have clinical implications. No EP starting dose adjustment based on patient demographics and other covariates was deemed necessary.

Etirinotecan pegol administration is associated with lower incidences of neutropenia compared to irinotecan administration.

PURPOSE: The relationship between incidences of neutropenia and 10-hydroxy-7-ethyl camptothecin (SN38) exposure was explored using SN38 pharmacokinetic and neutrophil count data from toxicology studies of etirinotecan pegol (EP) and irinotecan in beagle dogs. METHODS: Dogs received four weekly intravenous infusions of either vehicle control (n = 22), EP (6, 15, 20, 25, 40/25 mg/kg; n = 3-9 dogs/dose group/sex; n = 48), or irinotecan (20 or 25 mg/kg n = 3-4 dogs/dose group/sex; n = 14). Blood samples were collected up to 50 days post-dose for characterization of SN38 pharmacokinetics. Two separate models were created describing SN38 concentration time profiles after either irinotecan or EP administrations to project the AUC0-168h after Day 1 and Day 22 doses. The relationship between incidence of neutropenia and SN38 exposure was explored using logistic regression. RESULTS: The incidence of neutropenia in dogs receiving weekly doses of irinotecan or EP was strongly correlated with maximum plasma SN38 concentration (C max), but not SN38 area under the concentration-time curve (AUC). Neutropenia occurred in approximately 80% of dogs receiving irinotecan (mean SN38 C max of 13.5 and 26.3 ng/mL for 20 and 25 mg/kg, respectively). No neutropenia occurred in dogs receiving EP at doses up to and including 25 mg/kg (mean SN38 C max of 3.4 and 4.9 ng/mL for 20 and 25 mg/kg, respectively), despite 2.5-3.6 times greater SN38 AUC after EP compared to irinotecan at equivalent doses. CONCLUSIONS: EP administration avoids both high SN38 C max values and development of dose-limiting neutropenia observed after irinotecan, while maintaining greater and sustained SN38 exposure between doses.

Safety, tolerability, pharmacokinetics, and pharmacodynamic effects of naloxegol at peripheral and central nervous system receptors in healthy male subjects: A single ascending-dose study.

This randomized, double-blind, placebo-controlled, ascending-dose, crossover study evaluated single oral doses of naloxegol (NKTR-118; 8, 15, 30, 60, 125, 250, 500, and 1000 mg), a PEGylated derivative of naloxone, for safety and tolerability, antagonism of peripheral and central nervous system (CNS) effects of intravenous morphine, and pharmacokinetics. Healthy men were randomized 1:1 to naloxegol or naloxegol-matching placebo administered with morphine and lactulose in a 2-period crossover design. Periods were separated by a 5- to 7-day washout. Assessments included safety, tolerability, orocecal transit time (OCTT), pupillary miosis, and pharmacokinetics. The study was completed by 46 subjects. The most common adverse events were somnolence, dizziness, headache, and nausea. Greater reversal of morphine-induced delay in OCTT occurred with increasing naloxegol dose, demonstrating dose-ordered antagonism of morphine's peripheral gastrointestinal effects. Forty-four subjects showed no reversal of pupillary miosis; 2 showed potential partial reversal at 250 and 1000 mg, indicating negligible antagonism of morphine's CNS effects at doses ≤ 125 mg. Rapid absorption, linear pharmacokinetics up to 1000 mg, and low to moderate between-subject pharmacokinetic variability was observed. The pharmacokinetics of morphine or its glucuronide metabolites were unaltered by concurrent naloxegol administration. Naloxegol was generally safe and well tolerated at single doses up to 1000 mg.

Safety, tolerability, and pharmacokinetics of multiple ascending doses of naloxegol.

Opioid-induced constipation (OIC) is the most common and often a treatment-limiting adverse event (AE) of opioid therapy for chronic pain. Naloxegol (previously NKTR-118), a PEGylated derivative of naloxone that has minimal penetration of the central nervous system, has received regulatory approval as an oral therapy for OIC. This randomized, double-blind, placebo-controlled, multiple-dose, dose-escalation study was performed to assess safety, tolerability, and pharmacokinetics of multiple doses of naloxegol in healthy volunteers. Four cohorts, each with 4 male and 4 female volunteers, were randomized 3:1 to a twice-daily naloxegol solution (25, 60, 125, and 250 mg) or matching placebo solution. Doses were given every 12 hours for 7 days, with a single final dose on the morning of day 8. All 32 subjects completed the study. The incidence of most AEs was similar in the naloxegol and placebo groups; no AE led to study discontinuation. Naloxegol was rapidly absorbed. Plasma naloxegol pharmacokinetics showed dose proportionality, negligible accumulation at steady state, and no sex differences. Naloxegol in doses up to 250 mg every 12 hours was generally safe and well tolerated in this healthy volunteer population.

Clinical pharmacokinetics and pharmacodynamics of inhaled insulin.

The benefits of intensive insulin therapy in the prevention of complications in patients with diabetes mellitus are now well established. However, the current methods of insulin administration fall well short of the ideal. Consequently, alternative routes of insulin administration have been investigated. The pulmonary route has received the most attention, helped by advances in inhaler devices and insulin formulation technology. As a result, several insulin inhalation systems are at varying stages of development, with one already filed for marketing approval in Europe. Knowledge of the pharmacokinetic and pharmacodynamic characteristics of the various inhaled insulin formulations will help to determine their positioning in current and evolving diabetes treatment strategies. For instance, a rapid onset and short duration of action would be desirable for use in postprandial glucose control. Pharmacokinetic studies with inhaled insulin reveal that serum insulin concentrations peak earlier and decay more rapidly following inhalation compared with subcutaneously administered regular insulin, and pharmacodynamic studies measuring glucose infusion rate under euglycaemic glucose clamp show corresponding rapid changes in glucose control. Furthermore, intrapatient variability in the pharmacokinetics and pharmacodynamics of inhaled insulin is low; variability is similar to (or perhaps less than) that seen when insulin is administered subcutaneously. Estimates of the bioavailability and bioefficacy achievable with the current inhalation systems are typically in the region of 10% of that experienced with subcutaneously administered insulin. Most of the losses are in the device, mouth and throat, with approximately 30-50% of the insulin deposited in the lungs being absorbed. Clinical experience to date indicates that inhaled insulin has the potential to be an effective treatment in patients with diabetes, and that it may have particular utility in the treatment of postprandial hyperglycaemia.

The effect of food on the bioavailability of norethindrone and ethinyl estradiol from norethindrone acetate/ethinyl estradiol tablets intended for continuous hormone replacement therapy.

As part of the development of a combination product containing norethindrone acetate and low-dose ethinyl estradiol for continuous hormone replacement therapy in postmenopausal women, a study was conducted to determine the effect of a high-fat meal on the bioavailability of norethindrone and ethinyl estradiol from tablets containing 1 mg norethindrone acetate/10 micrograms ethinyl estradiol. Eighteen healthy postmenopausal women participated in an open-label, single-dose, randomized, three-way crossover study in which 2 x 1/10 norethindrone acetate/ethinyl estradiol tablets were administered fasting and with a high-fat breakfast, and the same dose was administered in solution. Following each treatment, serial blood samples were collected for 48 hours, and plasma ethinyl estradiol and norethindrone concentrations were determined by a validated gas chromatography/mass spectrometry (GC/MS) method. Individual plasma ethinyl estradiol and norethindrone pharmacokinetic parameters were calculated by noncompartmental methods for each treatment and analyzed by ANOVA to obtain differences between least squares treatment mean values and associated 90% confidence intervals. Rates of ethinyl estradiol and norethindrone availability from tablets administered with food were slower than availability rates from tablets administered while fasting. Systemic exposure to ethinyl estradiol was unaffected by administration of tablets with food, whereas exposure to norethindrone increased by 27%. Because administration of norethindrone acetate/ethinyl estradiol 1/10 tablets with a high-fat meal did not decrease systemic exposure to norethindrone and ethinyl estradiol, this formulation can be taken without regard to meals.

Nonclinical pharmacokinetics and activity of etirinotecan pegol (NKTR-102), a long-acting topoisomerase 1 inhibitor, in multiple cancer models.

PURPOSE: The aim of the study was to demonstrate the activity of etirinotecan pegol, a polymer conjugate of irinotecan, in multiple human tumor models and to establish both the pharmacokinetic/pharmacodynamics (PK/PD) relationship and clinical relevance of the findings. EXPERIMENTAL DESIGN: Anti-tumor activity was evaluated in mouse models of human lung, colorectal, breast, ovarian, and gastric cancers. Etirinotecan pegol was administered intravenously (once or every 3-7 days) to animals with established tumors. Activity was assessed by tumor growth delay (TGD) and regression. Mice bearing established colorectal and lung tumors were treated with etirinotecan pegol or irinotecan, and serial blood and tumor samples were collected at planned times between 0 and 60 days post-treatment for quantitation of etirinotecan pegol and SN38. For PK analysis, analyte concentration-time data were fit with compartmental models; PK/PD analysis was based on an inhibitory E max response model. RESULTS: Etirinotecan pegol was active in all tumor models. TGD was sustained for 2-10 weeks after last dose, while conventional irinotecan resulted in little suppression of tumor growth. Etirinotecan pegol was eliminated very slowly from the tumor (t 1/2 = 17 days), achieving higher and more sustained tumor exposure when compared with conventional irinotecan. The increased tumor exposure following etirinotecan pegol correlated with strong and prolonged suppression of tumor growth. Sustained plasma exposure to active SN38 was consistently observed across nonclinical species (including mouse, rat, and dog) and translated to cancer patients. CONCLUSIONS: Etirinotecan pegol is the first long-acting topoisomerase 1 inhibitor that provides sustained exposure, which results in prolonged anti-tumor activity in a wide variety of cancer models.

A multicenter, phase I, dose-escalation study to assess the safety, tolerability, and pharmacokinetics of etirinotecan pegol in patients with refractory solid tumors.

PURPOSE: This study was designed to establish the maximum tolerated dose (MTD) and to evaluate tolerability, pharmacokinetics, and antitumor activity of etirinotecan pegol. EXPERIMENTAL DESIGN: Patients with refractory solid malignancies were enrolled and assigned to escalating-dose cohorts. Patients received 1 infusion of etirinotecan pegol weekly 3 times every 4 weeks (w × 3q4w), or every 14 days (q14d), or every 21 days (q21d), with MTD as the primary end point using a standard 3 + 3 design. RESULTS: Seventy-six patients were entered onto 3 dosing schedules (58-245 mg/m(2)). The MTD was 115 mg/m(2) for the w × 3q4w schedule and 145 mg/m(2) for both the q14d and q21d schedules. Most adverse events related to study drug were gastrointestinal disorders and were more frequent at higher doses of etirinotecan pegol. Late onset diarrhea was observed in some patients, the frequency of which generally correlated with dose density. Cholinergic diarrhea commonly seen with irinotecan treatment did not occur in patients treated with etirinotecan pegol. Etirinotecan pegol administration resulted in sustained and controlled systemic exposure to SN-38, which had a mean half-life of approximately 50 days. Overall, the pharmacokinetics of etirinotecan pegol are predictable and do not require complex dosing adjustments. Confirmed partial responses were observed in 8 patients with breast, colon, lung (small and squamous cell), bladder, cervical, and neuroendocrine cancer. CONCLUSION: Etirinotecan pegol showed substantial antitumor activity in patients with various solid tumors and a somewhat different safety profile compared with the irinotecan historical profile. The MTD recommended for phase II clinical trials is 145 mg/m(2) q14d or q21d.

Pharmacokinetics and tolerability of BAY41-6551 in subjects with chronic kidney disease.

UNLABELLED: Abstract Background: BAY41-6551, a drug-device combination in development for adjunctive treatment of Gram-negative pneumonia in mechanically ventilated patients, consists of amikacin formulated for inhalation coupled with the Pulmonary Drug Delivery System (PDDS) Clinical aerosol delivery platform. This study evaluated safety, tolerability, and pharmacokinetics (PK) of BAY41-6551 in subjects with chronic kidney disease (CKD). METHODS: Single doses of BAY41-6551 (400 mg amikacin) were administered using the PDDS Clinical handheld device to six subjects with mild-to-moderate (Group 1) and six subjects with severe renal impairment (Group 2). Seven subjects with end-stage renal disease (ESRD; Group 3) received single doses of BAY41-6551 on days 1 and 9, with hemodialysis (HD) scheduled 24 h postdose on day 1 and 3 h postdose on day 9. PK analysis was performed on serum, urine, and dialysate samples (Group 3). RESULTS: Individual serum amikacin concentrations in Groups 1 and 2 were below 6 mg/L at all times [mean maximum serum drug concentration (C(max)) 0.94 mg/L and 2.46 mg/L, respectively). In Group 3, serum amikacin concentrations decreased after each HD session, and amikacin area under the serum concentration-time curve from zero to 72 h (AUC(72)) and C(max) values were lower on day 9 than on day 1 (mean AUC(72) 71.5 mg · h/L vs. 151.5 mg · h/L; mean C(max) 2.09 mg/L vs. 6.16 mg/L). The amounts of amikacin removed by HD and the dialysate clearance rates were similar on days 1 and 9. No serious adverse events were reported. CONCLUSIONS: Single doses of BAY41-6551 were well tolerated in subjects with CKD. HD effectively removed amikacin from serum in subjects with ESRD, and the timing relative to BAY41-6551 administration was an important determinant of systemic amikacin exposure. Nevertheless, standard precautionary measures for intravenous amikacin should apply for patients receiving BAY41-6551, and dose adjustments and/or dialysis should be considered for subjects with severe renal impairment.

Pharmacokinetics and tolerability of amikacin administered as BAY41-6551 aerosol in mechanically ventilated patients with gram-negative pneumonia and acute renal failure.

BACKGROUND: BAY41-6551, a drug-device combination in development for adjunctive treatment of Gram-negative pneumonia in intubated and mechanically ventilated patients, consists of amikacin formulated for inhalation coupled with the Pulmonary Drug Delivery System (PDDS) Clinical aerosol delivery platform. Given the predominantly renal clearance of aminoglycosides, understanding systemic amikacin exposure and safety during administration of BAY41-6551 to patients with acute renal failure (ARF) is clinically important. METHODS: Seven mechanically ventilated patients with Gram-negative pneumonia and ARF receiving continuous veno-venous hemodiafiltration (CVVHDF) were treated with multiple administrations of BAY41-6551 400 mg amikacin twice daily using the PDDS Clinical on-ventilator device [in addition to standard intravenous (i.v.) antimicrobial therapy]. CVVHDF parameters were recorded and a PK analysis was performed using serum, urine, and bronchoalveolar lavage fluid samples. RESULTS: Maximum serum amikacin concentration [median 1.93 (range: 0.63-3.99) mg/L] and area under the concentration-time curve from zero to 12 h on day 3 [median 19.32 (range 6.32-36.87) mg · h/L] were elevated compared with mechanically ventilated patients with normal renal function; however, serum amikacin trough concentrations were within accepted safety limits. The median amikacin concentration in epithelial lining fluid [887 (range: 406-12,819) mg/L] was similar to that reported previously in mechanically ventilated patients with normal renal function. BAY41-6551 demonstrated acceptable safety and tolerability with most adverse events (AEs) as expected for the patient population. One serious AE of bronchospasm was attributed to the study medication; no reported AEs were related to the PDDS Clinical device. CONCLUSIONS: CVVHDF appears to provide adequate clearance of systemically absorbed amikacin in mechanically ventilated patients with ARF, suggesting that dose adjustments for BAY41-6551 are probably not necessary for this patient population. Nonetheless, the standard precautionary measures for critically ill patients receiving i.v. amikacin should be followed for patients with ARF who are treated with BAY41-6551.

Lung deposition and pharmacokinetics of cyclosporine after aerosolization in lung transplant patients.

PURPOSE: Aerosolized cyclosporine (aCsA) has proven to be an effective therapy for refractory acute and chronic rejection in lung transplant (LTx) patients. The objective of this study is to evaluate the lung deposition and systemic absorption of aCsA after aerosolized cyclosporine administration in LTx patients in the immediate postoperative period. METHOD: Cyclosporine (CsA) was administered intravenously (1.0 mg/kg) to eight LTx patients, and multiple blood samples were collected over 24 h. At least 24 h later, aCsA (300 mg in propylene glycol) was administered to the same patients using nebulization and multiple blood samples were obtained again. Five patients had an additional inhalational gamma scintigraphy study with aCsA and 99MTc-labeled albumin to measure drug deposition. RESULTS: Peak blood concentrations of CsA after aerosol administration ranged from 119-402 ng/ml, and concentrations at 24 h ranged from 9-48 ng/ml. The rate of decline in drug concentration in blood in the apparent elimination phase was notably slower after administration of aCsA than after IV infusion. Terminal disposition half life (t 1/2 lambda(z)) values ranged from 4.1-9.9 h (mean 6.5 h) following IV administration and from 23.1 to 65.2 h (mean 40.7 h) following pulmonary administration, suggesting that drug absorption occurred throughout the 24-h sampling period following pulmonary administration. Deconvolution analysis indicated biphasic absorption of CsA from the lung in all patients, characterized by rapid initial absorption (absorption half-life 0.73 +/- 0.38 h) over the first 4 to 6 h followed by slower, sustained absorption throughout the remainder of the sampling period (absorption half-life 16.2 +/- 13.2 h). The absolute bioavailability of CsA after aerosol administration ranged from 5.4-11.2% (mean 8.2%) of the dose placed in the nebulizer. The total dose delivered to the lung estimated from scintigraphy ranged from 17.8-39.3 mg, and was in approximate agreement with the amount of drug absorbed, estimated using deconvolution. Essentially all drug deposited in the lungs was systemically absorbed. CONCLUSIONS: This study documents that cyclosporine can be effectively delivered by aerosolization to the lung of transplant patients in the early postoperative period. Part of the cyclosporine deposited in the lung is absorbed rapidly into systemic circulation and a portion is absorbed slowly but completely over a prolonged period.

Improved lung delivery from a passive dry powder inhaler using an Engineered PulmoSphere powder.

PURPOSE: To assess the pulmonary deposition and pharmacokinetics of an engineered PulmoSphere powder relative to standard micronized drug when delivered from passive dry powder inhalers (DPIs). METHODS: Budesonide PulmoSphere (PSbud) powder was manufactured using an emulsion-based spray-drying process. Eight healthy subjects completed 3 treatments in crossover fashion: 370 microg budesonide PulmoSphere inhaled from Eclipse DPI at target PIF of 25 L x min(-1) (PSbud25), and 50 L x min(-1) (PSbud50), and 800 microg of pelletized budesonide from Pulmicort Turbuhaler at 60 L x min(-1)(THbud60). PSbud powder was radiolabeled with 99mTc and lung deposition determined scintigraphically. Plasma budesonide concentrations were measured for 12 h after inhalation. RESULTS: Pulmonary deposition (mean +/- sd) of PSbud was 57+/-7% and 58+/-8% of the nominal dose at 25 and 50 L x min(-1), respectively. Mean peak plasma budesonide levels were 4.7 (PSbud25), 4.0 (PSbud50), and 2.2 ng x ml(-1) (THbud60). Median t(max) was 5 min after both PSbud inhalations compared to 20 min for Turbuhaler (P < 0.05). Mean AUCs were comparable after all inhalations, 5.1 (PSbud25), 5.9 (PSbud50), and 6.0 (THbud60) ng x h x ml(-1). The engineered PSbud powder delivered at both flow rates from the Eclipse DPI was twice as efficiently deposited as pelletized budesonide delivered at 60 L x min(-1) from the Turbuhaler. Intersubject variability was also dramatically decreased for PSbud relative to THbud. CONCLUSION: Delivery of an engineered PulmoSphere formulation is more efficient and reproducible than delivery of micronized drug from passive DPIs.