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.

Pharmacokinetics and acute safety of inhaled testosterone in postmenopausal women.

This was a preliminary feasibility study to assess the pharmacokinetics and acute safety of a single dose of orally inhaled testosterone via the AERx system, a novel handheld aerosol delivery system in postmenopausal women. Twelve postmenopausal women stabilized on oral estrogen therapy were treated with a single dose of testosterone (0.1, 0.2, or 0.3 mg) by inhalation. Plasma concentrations of sex steroids were measured between 1 and 360 minutes. Pulmonary and cardiovascular adverse events were monitored. Inhaled testosterone produced a dose-dependent increase in plasma total and free testosterone. At the highest dose (0.3 mg), total and free testosterone increased from baseline (mean +/- SD, 0.6 +/- 0.3 nmol/L, 2.5 +/- 1.0 pmol/L) to maximum levels of 62.6 +/- 20.4 nmol/L (total) and 168.2 +/- 50.2 pmol/L(free), occurring 1 to 2 minutes after dosing. A 2-compartment model best described the free and total testosterone pharmacokinetic profile. Dihydrotestosterone levels were higher than baseline at 60 minutes (P < .0002). Estradiol did not vary, but sex hormone binding globulin and albumin fell. There were no adverse events related to the treatment. Administration of inhaled testosterone is safe and achieves a supraphysiologic "pulse" kinetic profile of total and free testosterone with a rapid return to pretreatment levels.

Bolus inhalation of rhDNase with the AERx system in subjects with cystic fibrosis.

Inhaled recombinant human deoxyribonuclease (rhDNase) delivered by nebulizer improves pulmonary function and reduces the rate of pulmonary exacerbations in cystic fibrosis subjects. Standard jet nebulizers are relatively inefficient and require a delivery time of 10-20 min. We conducted an open-label, proof-of-concept study to evaluate whether bolus inhalation of rhDNase with a more efficient delivery system was safe and effective in cystic fibrosis subjects. The AERx system used for this study aerosolized 1.35 mg of rhDNase in three inhalations at a single sitting. The predicted AERx lung dose was approximately 0.68 mg, a dose consistent with lung doses of rhDNase given by jet nebulizer. In our 16 subjects with cystic fibrosis, a mean relative increase in FEV(1) of 7.8% (p < or = 0.001) was observed after 15 days of bolus delivery of rhDNase with the AERx system. The safety profile of rhDNase given as a bolus was similar to that observed with traditional nebulizer delivery. This study demonstrated that bolus inhalation of rhDNase was feasible, reasonably well-tolerated, and associated with improvement in pulmonary function in this small group of cystic fibrosis subjects.

Effect of gender and device mouthpiece shape on bolus insulin aerosol delivery using the AERx pulmonary delivery system.

PURPOSE: A study was designed to compare differences in insulin aerosol deposition profiles in healthy male and female subjects, as well as examine the effect of mouthpiece cross-sectional shape, volume, and taper on deposition profiles using a developmental AERx pulmonary delivery system. METHODS: Six mouthpieces were screened in the laboratory, and three were selected for clinical investigation: a cylindrical mouthpiece with constant-cross-sectional area, an elliptical mouthpiece with constant-cross-sectional area, and a tapered elliptical mouthpiece with an exit cross-sectional area equal to one half the entrance cross-sectional area. RESULTS: There was no significant difference in the lung dose or in the deposition pattern between males and females (p > 0.05, by ANOVA). The cross-sectional shape of the mouthpiece had no significant effect on the clinical lung dose or the deposition pattern (p > 0.05, by ANOVA), although in vitro testing showed lower emitted dose values with the tapered elliptical mouthpiece (by ANOVA and Duncan's multiple range test, alpha = 0.05). Using the tapered mouthpiece in the clinic resulted in significantly more deposition on the mouthpiece itself when compared to the nontapered mouthpieces. CONCLUSION: Inhalation of insulin using the AERx system was insensitive to differences in male and female respiratory tract geometry across all mouthpiece designs examined.

Evaluation of the AERx pulmonary delivery system for systemic delivery of a poorly soluble selective D-1 agonist, ABT-431.

PURPOSE: ABT-431 is a chemically stable, poorly soluble prodrug that rapidly converts in vivo to A-86929, a selective dopamine D-1 receptor agonist. This study was designed to evaluate the ability of the AERx pulmonary delivery system to deliver ABT-431 to the systemic circulation via the lung. METHODS: A 60% ethanol formulation of 50 mg/mL ABT-431 was used to prepare unit dosage forms containing 40 microL of formulation. The AERx system was used to generate a fine aerosol bolus from each unit dose that was collected either onto a filter assembly to chemically assay for the emitted dose or in an Andersen cascade impactor for particle size analysis. Plasma samples were obtained for pharmacokinetic analysis after pulmonary delivery and IV dosing of ABT-431 to nine healthy male volunteers. Doses from the AERx system were delivered as a bolus inhalation(s) (1, 2, 4, and 8 mg) and intravenous infusions were given over 1 hr (5 mg). Pharmacokinetic parameters of A-86929 were estimated using noncompartmental analysis. RESULTS: The emitted dose was 1.02 mg (%RSD = 11.0, n = 48). The mass median aerodynamic diameter of the aerosol was 2.9 +/- 0.1 microm with a geometric standard deviation of 1.3 +/- 0.1 (n = 15). Tmax (mean +/- SD) after inhalation ranged from 0.9 +/- 0.6 to 11.5 +/- 2.5. The mean absolute pulmonary bioavailibility (as A-86929) based on emitted dose ranged from 81.9% to 107.4%. CONCLUSIONS: This study demonstrated that the AERx pulmonary delivery system is capable of reproducibly generating fine nearly monodisperse aerosols of a small organic molecule. Aerosol inhalation utilizing the AERx pulmonary delivery system may be an efficient means for systemic delivery of small organic molecules such as ABT-431.