Safety, Tolerability, and Pharmacokinetics of NRL-1049, a Rho-Associated Kinase Inhibitor, in Healthy Volunteers: A...

Cerebral cavernous malformations (CCMs) are vascular lesions of the brain that can lead to hemorrhage, focal neurologic deficits, and seizures. Rho-associated kinase (ROCK) overactivation plays a critical role in the development of CCMs, and a novel, selective ROCK2 inhibitor, NRL-1049, mitigated lesion burden and bleeding in mouse models of CCM. This study examined the safety, tolerability, and pharmacokinetics of NRL-1049 in healthy volunteers.

In this first-in-human, randomized, double-blind, single-ascending dose study, participants received a single, oral dose of NRL-1049 (25, 75, 150, or 250 mg) or placebo in a fasted state (period 1). In period 2, participants received 150 mg NRL-1049 or placebo 30 min after a standardized high-fat, high-calorie meal. Blood samples for pharmacokinetic analysis were collected pre-dose and at post-dose time points from 5 min to 48 h. Treatment-emergent adverse events (TEAEs) were recorded and pharmacokinetic parameters determined, including maximum drug concentration (C_max), time to C_max (t_max), and area under the concentration-time curve (AUC) from time 0 to last quantifiable concentration (AUC_0-t) and extrapolated to infinity (AUC_0-∞).

Of the 24 participants in period 1 who received NRL-1049 (fasted), 9 (37.5%) experienced ≥ 1 TEAE, with 8 (33.3%) reporting ≥ 1 treatment-related TEAE. TEAEs appeared to correlate with dose, and 150 mg was the maximum tolerated dose following single-dose administration in this study. The most common TEAEs (> 5%) were dizziness (16.7%), headache (8.3%), and syncope (8.3%). In period 2 (n = 10), four (40.0%) participants who received 150 mg NRL-1049 (fed) reported ≥ 1 TEAE, and three (30.0%) reported a treatment-related TEAE. There were no reports of serious TEAEs or discontinuations due to a TEAE. NRL-1049 was rapidly absorbed in the fasted state, with median t_max ranging from 0.50 to 0.75 h. Mean C_max increased over the dose range of 25-250 mg (3.66-58.0 ng/mL). As NRL-1049 dose increased in a ratio of 1:3:6:10, mean C_max similarly increased (1:5:10:16), while AUC_0-t and AUC_0-∞ increased in a greater-than-dose proportional manner (1:5:11:25 and 1:4:10:21, respectively; P < 0.001). In the fed state (150 mg NRL-1049), mean C_max (18.5 ng/mL) was lower compared with the fasted state (34.9 ng/mL). For the active metabolite, NRL-2017, in the fasted state, median t_max was 0.88-1.63 h, and mean C_max increased over the dose range (54.2-1520 ng/mL). Mean C_max (1:6:14:28), AUC_0-t (1:4:7:14), and AUC_0-∞ (1:3:6:13) of NRL-2017 increased in a greater-than-dose proportional manner (P < 0.001). In the fed state, mean C_max was lower compared with the fasted state.

The maximum tolerated dose of 150 mg NRL-1049 was associated with a favorable safety profile in healthy adult volunteers. Exposure of NRL-1049 and its active metabolite, NRL-2017, increased in a dose proportional or greater-than-dose proportional manner. These results support continued investigation and development of NRL-1049.