Pharmacokinetics and Safety of Intramuscular Injectable Benzathine Penicillin G in Japanese Healthy Participants.

An intramuscular (IM) suspension of benzathine penicillin G (BPG) has been used as first-line therapy for the treatment of syphilis worldwide since its approval in the 1950s. However, there are limited reports about the pharmacokinetics of BPG. A Phase 1 study was conducted on eight Japanese healthy participants to investigate the pharmacokinetics (samples collected predose to 648 h post-dose) and safety of 2.4 million units of BPG after a single IM injection. Following administration, penicillin G, the active moiety of BPG, was absorbed slowly from the injection site with a median time to Cmax (tmax) of 48 h post-dose. After the achievement of Cmax, concentrations of penicillin G declined slowly in a monophasic fashion with a mean apparent terminal half-life of 189 h. Geometric mean AUCinf and Cmax were 50770 ng•h/mL and 259 ng/mL, respectively. Median time (range) above the well-accepted therapeutic concentration (18 ng/mL) for syphilis treatment was 561 h (439-608 h [18-25 days]), which reached and exceeded the necessary duration of 7-10 days for syphilis treatment. Two participants were underdosed with residual drug left in the syringe due to the high viscosity of the drug product. Only one (12.5%) participant reported a mild adverse event of nasopharyngitis, which was considered not related to the study treatment. The study results supported BPG approval in Japan as an option for syphilis treatment.

A multi-purpose Japanese phase I study in the global development of vupanorsen: Randomized, placebo-controlled, single-ascending dose study in adults.

Vupanorsen (PF-07285557) is a second-generation tri-N-acetyl galactosamine (GalNAc3 )-antisense oligonucleotide targeted to angiopoietin-like 3 (ANGPTL3) mRNA, shown to reduce lipids and apolipoproteins in subjects with dyslipidemia. To aid bringing innovative drugs to global patients efficiently, a multi-purpose Japanese phase I study was conducted, with integrated development approaches agreed by the Pharmaceuticals and Medical Devices Agency (PMDA). This randomized, double-blind, placebo-controlled, single-ascending dose (SAD) study investigated the safety, tolerability, pharmacokinetics, and pharmacodynamics of vupanorsen administered subcutaneously to Japanese adults (20-65 years) with elevated triglycerides (TG). Participants were randomized (1:1:1) to vupanorsen (80:160 mg) or placebo (N = 4 each). Vupanorsen 160 mg was a first-in-human (FIH) dose level. Vupanorsen was well-tolerated with no treatment-related adverse events reported for either dose. Absorption into the systemic circulation was rapid with median time to maximum concentration (Tmax ) of 3.5 and 2.0 h, for vupanorsen 80 and 160 mg, respectively. Following maximum concentration (Cmax ), vupanorsen underwent multiphasic decline characterized by a relatively fast initial distribution phase followed by slower terminal elimination phase, with elimination half-life (t1/2 ) of 397 and 499 h (80, 160 mg), respectively. Area under the concentration-time curve (AUC) and Cmax increased in a greater than dose-proportional manner. Pharmacodynamic markers (ANGPTL3, TG, and other key lipids) were reduced with vupanorsen versus placebo. Vupanorsen was safe and well-tolerated in healthy Japanese participants with elevated TG. This study provided FIH data for vupanorsen 160 mg. Moreover, the SAD study in Japanese participants fulfilled PMDA bridging requirements, and with the totality of global vupanorsen data, supported the PMDA waiver for a local phase II dose-finding study. ClinicalTrials.gov: NCT04459767.