Safety, tolerability, and pharmacokinetics (PK) of treprostinil palmitil inhalation powder (TPIP): a phase 1, randomised, double-blind, single- and multiple-dose study

Background/Introduction

Use of treprostinil in the treatment of pulmonary arterial hypertension (PAH) is limited by a short half-life and dose-limiting adverse events. TPIP, a dry powder formulation of the treprostinil prodrug treprostinil palmitil, is under investigation for PAH. In preclinical models, TPIP provided sustained treprostinil release in the lung and demonstrated sustained reduction of pulmonary arterial pressures.

Purpose

To examine the safety, tolerability, and PK of single- and multiple-dose administration of once-daily (QD) TPIP in healthy volunteers.

Methods

In this phase 1 study, healthy adults (aged 18–45 years) were randomised to receive single or multiple QD inhalation doses of TPIP. Single-dose participants received TPIP 112.5, 225, 450, or 675 μg (n=6 per dose) or placebo (n=2). Multiple-dose participants received TPIP 225 μg QD for 7 days (n=6), 112.5 μg QD for 4 days followed by 225 μg QD for 3 days (n=6), or placebo for 7 days (n=4).

Results

Of 42 randomly assigned participants who received ≥1 dose, 41 (97.6%) completed the study. Of the single-dose TPIP–treated participants, 70.8% (n=17/24) experienced a treatment-emergent adverse event (TEAE) vs 0% (0/2) of placebo-treated participants; the most common TEAEs (≥15%) among TPIP-treated participants were cough (45.8%), dizziness (29.2%), throat irritation (20.8%), nausea (16.7%), and hypotension (16.7%). Of the multiple-dose TPIP–treated participants, 83.3% (n=10/12) experienced a TEAE vs 50.0% of placebo-treated participants (2/4); the most common TEAEs were cough (58.3% TPIP vs 50.0% placebo), headache (50.0% vs 0%), nausea (33.3% vs 0%), and dizziness (25.0% vs 0%). Overall, 69.0% of participants (29/42) experienced mild TEAEs and 16.7% (7/42) experienced moderate TEAEs; no severe or serious TEAEs occurred. TEAEs were more frequent with increasing TPIP doses. Participants titrated from TPIP 112.5 μg QD to 225 μg QD experienced fewer TEAEs than those who received 225 μg QD at treatment initiation; all TEAEs were mild. After single-dose TPIP treatment, treprostinil exposure was dose proportional, with mean (CV%) Cmax = 78.4–717 pg/mL (38.6-72.9%) and AUC(0–∞) = 1.09–5.48 h·ng/mL (11.5–30.0%). At steady-state (225 μg), the mean (CV%) of Cmax, Cmin, and AUC(0–t) were 193–228 pg/mL (32.9–46.4%), 17.6–22.8 ng/mL (43.7%-64.4%) and 1.68–1.82 ng·h/mL (28.7–36.6%), respectively. No steady-state accumulation was observed. Elimination t1/2 was 8.7–11.6 h after a single dose and 6.8–8.8 h at steady state. Plasma concentrations of treprostinil palmitil were below the limit of quantification (100 pg/mL) at all time points measured.

Conclusions

In this phase 1 study, single and multiple TPIP dosing was generally well tolerated in healthy volunteers, with a PK profile that supports QD dosing. TEAEs were dose related; most were mild, none were severe or serious, and a titration schedule improved tolerability. These results support further examination of TPIP in patients with PAH.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Insmed Incorporated

Pharmacokinetics and pharmacodynamics of dapagliflozin in children and adolescents with type 2 diabetes mellitus

AIMS

To evaluate the pharmacokinetic (PK)/pharmacodynamic (PD) and safety profile of dapagliflozin in paediatric patients aged 10-17 years with type 2 diabetes mellitus (T2DM).

METHODS

Patients were randomized to a single oral dose of dapagliflozin 2.5, 5 or 10 mg. The PK characteristics for individual patients were derived by non-compartmental methods. Urinary glucose excretion (UGE), fasting plasma glucose (FPG) and ease of swallowing were also evaluated.

RESULTS

A total of 24 patients with a mean (range) body weight of 99.7 (61.5-169.5) kg received dapagliflozin. Dapagliflozin was rapidly absorbed after oral administration (median time to maximum plasma concentration ∼1.5 h) and systemic exposures to dapagliflozin and its 3-O-glucuronide metabolite appeared dose-proportional. The mean 24-h UGE increased in a dose-related manner (52.8, 62.4 and 89.0 g for the 2.5, 5 and 10 mg groups, respectively). Mean FPG concentrations were lower for all dose groups on day 2 (6.9, 6.2 and 6.8 mmol/l for 2.5, 5 and 10 mg groups, respectively) than they were predose on day 1 (9.5, 8.5 and 8.2 mmol/l for 2.5, 5 and 10 mg groups, respectively). Six patients (25%) experienced ≥1 adverse event (AE), however, there was no dose-related pattern. All AEs occurred only once and most were mild in intensity. Nearly all patients (n = 23; 95.8%) reported easy swallowing of the dapagliflozin tablets.

CONCLUSIONS

Dapagliflozin was well tolerated in this paediatric population, with no significant safety findings. PK/PD characteristics were similar to those observed in adults with T2DM, thereby supporting the hypothesis that the same dapagliflozin dosage as that used in adults can be evaluated in future phase III paediatric studies.