The Effect of Hepatic Impairment on the Pharmacokinetics of Intravenously Administered Felcisetrag (TAK-954).

Felcisetrag (formerly known as TAK-954) is a selective serotonin receptor agonist under investigation for use in patients with postoperative gastrointestinal dysfunction. The safety, tolerability, and pharmacokinetics (PK) of intravenous (i.v.) felcisetrag have been studied, but little is known about the effect of hepatic impairment on the PK of the drug. This phase 1, non-randomized, open-label study compared the PK of a single 60-minute i.v. infusion of felcisetrag between healthy individuals (n = 8) and patients with moderate (n = 10) or severe (n = 7) hepatic impairment. The primary study end points were the total and free maximum observed plasma concentration of felcisetrag at the end of infusion (Cmax ), area under the concentration-time curve (AUC) from time 0 to the time of the last quantifiable concentration (AUClast ), and AUC from time 0 to infinity (AUCinf ). Concentration-time profiles of felcisetrag were similarly shaped between groups but revealed lower concentrations of total plasma felcisetrag with increasing severity of hepatic impairment, whereas concentrations of free felcisetrag increased. The ratios of AUClast and AUCinf for patients with severe hepatic impairment were up to 29.3% lower for total felcisetrag and up to 29.2% higher for free felcisetrag than found in healthy individuals (P < .05). Infusions were well tolerated with no discontinuations, severe adverse events, or deaths during the study. Overall, the effect of hepatic impairment on exposure to felcisetrag was minimal, suggesting that dose adjustment may be unnecessary in patients with hepatic impairment.

Evaluation of the Pharmacokinetics of Felcisetrag (TAK-954), a 5-HT4 Receptor Agonist, in the Presence and Absence of Itraconazole, a Potent CYP3A4 Inhibitor.

The 5-hydroxytryptamine type-4 receptor agonist felcisetrag (TAK-954) is being investigated for improving gastrointestinal motility in postoperative gastrointestinal dysfunction. Polypharmacy often occurs in this setting, and as in vitro data indicate, felcisetrag is primarily metabolized by cytochrome P450 (CYP) 3A4, its CYP3A4-mediated drug-drug interaction potential requires consideration. This phase 1, fixed-sequence, open-label, crossover trial (ClinicalTrials.gov identifier NCT03173170) investigated the effect of itraconazole, a potent CYP3A4 inhibitor, on felcisetrag pharmacokinetics in healthy adults. Over 2 study periods (period 1, 6 days; period 2, 9 days), participants received a single felcisetrag 0.2-mg intravenous dose (day 1, period 1; and day 4, period 2), and once-daily oral itraconazole 200-mg doses (days 1-8, period 2). For felcisetrag alone, felcisetrag total systemic exposure was lower than with itraconazole coadministration. The geometric mean ratio for area under the plasma concentration-time curve from time 0 to infinity of felcisetrag plus itraconazole: felcisetrag alone was 1.49 (90% confidence interval, 1.39-1.60). Peak exposure was similar between regimens (geometric mean ratio, 1.06; 90% confidence interval, 0.96-1.18), and both treatments were well tolerated. These data suggest limited CYP3A4-mediated drug-drug interaction inhibition for felcisetrag.

Reduced sodium transport with nasal administration of the prostasin inhibitor camostat in subjects with cystic fibrosis.

BACKGROUND: Prostasin, a trypsin-like serine protease, is a channel-activating protease and major regulator of epithelial sodium channel-mediated sodium absorption. Its direct inhibition by camostat represents a potential approach to inhibiting sodium transport in cystic fibrosis (CF). METHODS: To determine whether a topical formulation of camostat represents an efficacious and tolerable approach to reducing Na+ transport in the CF airway, we conducted a two-part randomized, double-blind, placebo-controlled, crossover, ascending single-dose study to evaluate the pharmacodynamics, safety, and pharmacokinetics of camostat administered through a nasal spray pump in subjects with CF. Nasal potential difference (PD) was measured before and after treatment, and safety and pharmacokinetics were assessed by a standardized approach. RESULTS: In part 1, nine subjects were enrolled, and six completed crossover dosing at the maximally tolerated dose. The change in maximal (most polarizing) basal PD 2 h following administration of camostat was +13.1 mV (1.6-mg dose group) compared with -8.6 mV following placebo (P<.005). Intrasubject change in Ringer and amiloride-sensitive PDs exhibited similar and consistent responses. Bayesian analysis in an additional six subjects in part 2 estimated a dose of 18 µg/mL to provide 50% of the maximum effect. There was no significant change in chloride transport or total nasal symptom score, nasal examination rating, and laboratory parameters. CONCLUSIONS: This study establishes the proof of concept that a reduction in sodium transport in the human CF airway can be achieved through inhibition of prostasin activity, identifying a potential therapeutic target in the disease. TRIAL REGISTRATION: ClinicalTrials.gov; No.: NCT00506792; URL: www.clinicaltrials.gov.

Challenges in inhaled product development and opportunities for open innovation.

Dosimetry, safety and the efficacy of drugs in the lungs are critical factors in the development of inhaled medicines. This article considers the challenges in each of these areas with reference to current industry practices for developing inhaled products, and suggests collaborative scientific approaches to address these challenges. The portfolio of molecules requiring delivery by inhalation has expanded rapidly to include novel drugs for lung disease, combination therapies, biopharmaceuticals and candidates for systemic delivery via the lung. For these drugs to be developed as inhaled medicines, a better understanding of their fate in the lungs and how this might be modified is required. Harmonized approaches based on 'best practice' are advocated for dosimetry and safety studies; this would provide coherent data to help product developers and regulatory agencies differentiate new inhaled drug products. To date, there are limited reports describing full temporal relationships between pharmacokinetic (PK) and pharmacodynamic (PD) measurements. A better understanding of pulmonary PK and PK/PD relationships would help mitigate the risk of not engaging successfully or persistently with the drug target as well as identifying the potential for drug accumulation in the lung or excessive systemic exposure. Recommendations are made for (i) better industry-academia-regulatory co-operation, (ii) sharing of pre-competitive data, and (iii) open innovation through collaborative research in key topics such as lung deposition, drug solubility and dissolution in lung fluid, adaptive responses in safety studies, biomarker development and validation, the role of transporters in pulmonary drug disposition, target localisation within the lung and the determinants of local efficacy following inhaled drug administration.

Emerging therapies for respiratory diseases.

This Society for Medicines Research symposium, sponsored by UCB, was held on September 11, 2007, at the Wellcome Trust Conference Centre, Hinxton, Cambridge, United Kingdom. The meeting, organized by Ruth Lock, Steve Collingwood and Andrew Ratcliffe, reviewed current thinking in the area of airway drug delivery and the challenges and progress made in the discovery and development of novel medicines to treat respiratory diseases, such as chronic obstructive pulmonary disease, asthma, allergic rhinitis and cystic fibrosis.