First-in-Human Studies to Evaluate the Safety, Tolerability, and Pharmacokinetics of a Novel 5-HT₄ Partial Agonist, SUVN-D4010, in Healthy Adult and Elderly Subjects

SUVN-D4010 is a novel, potent, highly selective 5-HT₄ partial agonist intended for the treatment of cognitive disorders. The objective of the clinical study was to characterize the safety, tolerability, and pharmacokinetics of SUVN-D4010 in healthy adults after single and multiple doses, and to evaluate the effect of food, sex, and age on the pharmacokinetics.

Single-ascending dose and multiple-ascending dose studies for 14 days were conducted in healthy adults using a randomized, double-blind design. The effects of food, sex, and age on SUVN-D4010 pharmacokinetics (25 mg single dose) were evaluated using an open-label, two-period, randomized, fed and fasted, crossover design. Pharmacokinetics and safety assessments were conducted throughout the study.

SUVN-D4010 at a single dose up to 45 mg and multiple doses up to 40 mg once daily was found to be safe and well tolerated in healthy adults. The most frequently reported adverse events were headache and nausea. SUVN-D4010 exposure was dose proportional across the tested doses. Steady state was achieved on day 2 after once-daily dosing for 14 days. Food had no significant effect on the exposures but an increase in median time to attain the maximum plasma concentration (t_max) from 2 h in a fasted state to 3.5 h in fed state was observed. The maximum plasma concentration (C_max) and the area under the concentration-time curve (AUC) of SUVN-D4010 was 37% and 39%, respectively, lower in adult females compared to males following administration of a single 25 mg dose. In the elderly population, C_max and AUC of SUVN-D4010 were 42% and 37%, respectively, lower compared to adult males following administration of a single 25 mg dose. SUVN-D4010 was well tolerated and safe in elderly subjects (≥ 65 years) following a single 25 mg dose.

SUVN-D4010 was found to be safe and well tolerated in healthy human subjects. SUVN-D4010 followed linear pharmacokinetics across the dose range. Accumulation was in the range of 1.3- to 1.4-fold after multiple dosing. Renal excretion is not the major route of elimination. Food had no effect on the exposures but increased the t_max of SUVN-D4010. Exposures were lower in females and elderly subjects suggesting sex and age effects on the pharmacokinetics of SUVN-D4010 and possible dose adjustment in these populations. SUVN-D4010 was well tolerated and safe in elderly subjects after a single dose.

Clinical trial identifiers: NCT02575482 and NCT03031574.