A Phase I Study to Investigate the Absorption, Pharmacokinetics, and Excretion of [(14)C]Prucalopride After a Single Oral Dose in Healthy Volunteers

PURPOSE

Chronic constipation is a prevalent gastrointestinal disorder globally. It is often treated with medications such as laxatives. Newer therapies to improve gastric motility include the selective 5-hydroxytryptamine receptor-4 agonist prucalopride, which is licensed for the treatment of chronic constipation in adults. The aim of this study was to investigate the pharmacokinetic properties and excretion of prucalopride in healthy individuals, using a microtracer approach with (14)C radioactivity detection using liquid scintillation counting and accelerator mass spectrometry.

METHODS

This was a single-period, open-label, nonrandomized absorption, metabolism, and excretion study of [(14)C]prucalopride. Participants were 6 healthy men aged 18 to 50 years. After screening, participants were administered a single dose of [(14)C]prucalopride succinate 2 mg (~200 nCi). Postadministration, urine, feces, and blood samples were collected over a 10-day period. Safety and adverse event data were also collected.

FINDINGS

Almost 100% of the administered dose of radioactivity was recovered, with a mean (SD) of 84.2% (8.88%) recovered in urine and 13.3% (1.73%) recovered in feces. The mean blood-to-plasma concentration ratio of 1.9 indicated uptake of prucalopride into blood cells. The renal clearance of prucalopride was 17.0 (2.5) L/h, which is higher than the glomerular filtration rate in healthy individuals, suggesting active renal transport of prucalopride. Prucalopride was well tolerated, with no serious adverse events reported.

IMPLICATIONS

Prucalopride was well absorbed and excreted mainly by the kidneys, including both passive and active transporter mechanisms. Quantitative recovery of the radioactive dose was achieved. Consistent with previous studies, prucalopride was generally well tolerated. ClinicalTrials.gov identifier: NCT01807000.

Prucalopride induces high-amplitude propagating contractions in the colon of patients with chronic constipation: a randomized study

BACKGROUND

This study compared prucalopride, a selective, prokinetic, 5-HT4 receptor agonist, with polyethylene glycol 3350 + electrolytes (PEG3350), an osmotic laxative, on colonic motility parameters, primarily high-amplitude propagating contractions (HAPCs) in patients with chronic constipation.

METHODS

This randomized, cross-over, reader-blinded study was conducted at a single site in the USA. The study was open to men and women aged 18-75 years who met study inclusion criteria. Colonic manometry catheters were inserted the day before investigation. On the investigation days, patients received oral 2 mg prucalopride or 2 × 13.8 g PEG3350 in solution. The primary endpoint was HAPC count (threshold: mean amplitude ≥100 mmHg, propagation ≥20 cm [HAPC1 ]) in the 12 h after treatment administration. Analyses were also conducted at two co-primary thresholds: mean amplitude ≥75 mmHg, propagation ≥20 cm (HAPC2 ); and mean amplitude ≥75 mmHg, propagation ≥10 cm (HAPC3 ). Secondary endpoints included HAPC area under the curve (AUC), contraction force, amplitude, duration, and propagation velocity.

KEY RESULTS

Thirteen women were enrolled, with 12 completing the study. Significantly more HAPC1 (8.7 ± 2.06 vs 2.9 ± 2.06; p = 0.012) and HAPC2 (9.0 ± 2.11 vs 3.3 ± 2.11; p = 0.017) were observed in the 12-h periods with prucalopride than with PEG3350. Prucalopride significantly increased mean propagation distance and velocity (HAPC2 ) and mean AUC, force, and amplitude (HAPC3 ) compared with PEG3350. Adverse events were mild or moderate.

CONCLUSIONS & INFERENCES

Prucalopride was superior to PEG3350 in inducing HAPCs in patients with chronic constipation. ClinicalTrials.gov number NCT01707667.

Comparison of dietary phosphate absorption after single doses of lanthanum carbonate and sevelamer carbonate in healthy volunteers: a balance study

BACKGROUND

Lanthanum carbonate and sevelamer carbonate are noncalcium phosphate binders used to treat hyperphosphatemia in patients with chronic kidney disease. This is the first study to compare phosphate absorption from a standardized meal ingested with a typical clinical dose of these binders.

STUDY DESIGN

Randomized open-label crossover study.

SETTINGS & PARTICIPANTS

Healthy volunteers were confined to a clinical research center during 4 study periods. Of 31 volunteers randomly assigned, 19 completed all treatments and 18 were analyzed in the pharmacodynamic set (1 was excluded because of vomiting).

INTERVENTION

Participants were assigned in random order to meal alone, meal plus lanthanum carbonate (1 tablet containing 1,000 mg of elemental lanthanum), and meal plus sevelamer carbonate (three 800-mg tablets). The gastrointestinal tract was cleared, the meal was ingested (± treatment), and rectal effluent was collected. In a fourth period, volunteers repeated the study procedures while fasting.

OUTCOMES

The primary end point, net phosphate absorption, was analyzed using a mixed-effect linear model.

MEASUREMENTS

Phosphorus content of effluent and duplicate meal samples were measured using inductively coupled plasma-optical emission spectroscopy.

RESULTS

The standard meal contained ∼375 mg of phosphate, 75% of which was absorbed (net absorption, 281.7 ± 14.1 mg [adjusted mean ± standard error]). Lanthanum carbonate decreased net phosphate absorption by 45% (net absorption, 156.0 ± 14.2 mg) compared with 21% (net absorption, 221.8 ± 14.1 mg) for sevelamer carbonate (P < 0.001). Lanthanum carbonate bound 135.1 ± 12.3 mg of phosphate, whereas sevelamer carbonate bound 63.2 ± 12.3 mg, a 71.9-mg difference (95% CI, 40.0-103.8; P < 0.001). Per tablet, this equates to 135 mg of phosphate bound with lanthanum carbonate versus 21 mg with sevelamer carbonate.

LIMITATIONS

A single-dose study.

CONCLUSIONS

In healthy volunteers, 1,000 mg of lanthanum carbonate decreased phosphate absorption by 45% compared with a 21% decrease with 2,400 mg of sevelamer carbonate.