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

The oral Janus kinase/spleen tyrosine kinase inhibitor ASN002 demonstrates efficacy and improves associated systemic inflammation in patients with moderate-to-severe atopic dermatitis: results from a randomized double-blind placebo-controlled study

BACKGROUND

ASN002 is an oral dual inhibitor of Janus kinase and spleen tyrosine kinase, which are involved in the pathogenesis of atopic dermatitis (AD) through their regulatory role on T helper (Th)1, Th2 and Th17/Th22 pathways.

OBJECTIVES

The objectives of this study were to evaluate the efficacy, safety, pharmacokinetics and effects on systemic biomarkers of ASN002 in patients with moderate-to-severe AD. Methods A total of 36 patients with moderate-to-severe AD were randomized (3 : 1) to ASN002 or placebo in the phase Ib study. Three dosage cohorts were studied over a 28-day period (20 mg, 40 mg and 80 mg once daily).

RESULTS

ASN002 was superior to placebo for the proportion of patients achieving Eczema Area and Severity Index (EASI) 50 (20 mg 20%, P = 0·93; 40 mg 100%, P = 0·003; 80 mg 83%, P = 0·03; placebo 22%), EASI 75 (20 mg 0%, P = 0·27; 40 mg 71%, P = 0·06; 80 mg 33%, P = 0·65; placebo 22%) and in change from baseline in pruritus (20 mg -1·3 ± 2·1, P = 0·81; 40 mg -3·1 ± 2·7, P = 0·27; 80 mg -4·7 ± 2·1, P = 0·01; placebo -1·6 ± 1·8). Adverse events were generally mild and similar across all groups. ASN002 showed dose-dependent plasma exposure with low interpatient variability, significantly downregulated several serum biomarkers involved in Th1, Th2 and Th17/Th22 immunity, and decreased the atherosclerosis-associated biomarker E selectin/SELE.

CONCLUSIONS

In patients with moderate-to-severe AD, ASN002 showed strong efficacy with rapid onset of action and associated improvements in systemic inflammation.

The pharmacology of bimatoprost (Lumigan)

Bimatoprost (Lumigan) is a pharmacologically unique and highly efficacious ocular hypotensive agent. It appears to mimic the activity of a newly discovered family of fatty acid amides, termed prostamides. One biosynthetic route to the prostamides involves anandamide as the precursor. Bimatoprost pharmacology has been extensively characterized by binding and functional studies at more than 100 drug targets, which comprise a diverse variety of receptors, ion channels, and transporters. Bimatoprost exhibited no meaningful activity at receptors known to include antiglaucoma drug targets as follows: adenosine (A(1-3)), adrenergic (alpha(1), alpha(2), beta(1), beta(2)), cannabinoid (CB(1), CB(2)), dopamine (D(1-5)), muscarinic (M(1-5)), prostanoid (DP, EP(1-4), FP, IP, TP), and serotonin (5HT(1-7)). Bimatoprost does, however, exhibit potent inherent pharmacological activity in the feline iris sphincter preparation, which is prostamide-sensitive. Bimatoprost also resembles the prostamides in that it is a potent and highly efficacious ocular hypotensive agent. A single dose of bimatoprost markedly reduces intraocular pressure in dogs and laser-induced ocular hypertensive monkeys. Decreases in intraocular pressure are well maintained for at least 24 hr post-dose. Human studies have demonstrated that systemic exposure to bimatoprost is low and that accumulation does not occur. The sclera is the preferred route of accession to the eye. The high scleral permeability coefficient Papp is a likely contributing factor to the rapid onset and long-acting ocular hypotensive profile of bimatoprost.