Pharmacokinetics and Tolerability of the Novel Non-immunosuppressive Fingolimod Derivative, OSU-2S, in Dogs and Comparisons with Data in Mice and Rats

Zhiliang Xie, Min Chen, Swagata Goswami, Rajes Mani, Dasheng Wang, Samuel K. Kulp, Chris C. Coss, Larry J. Schaaf, Fengyu Cui, John C. Byrd, Ryan N. Jennings, Karsten K. Schober, Carrie Freed, Stephanie Lewis, Raphael Malbrue, Natarajan Muthusamy, Chad Bennett, William C. Kisseberth, Mitch A. Phelps

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


In this study, we characterized the pharmacokinetics of OSU-2S, a fingolimod-derived, non-immunosuppressive phosphatase activator, in mice, rats, and dogs, as well as tolerability and food effects in dogs. Across all species tested, plasma protein binding for OSU-2S was > 99.5%, and metabolic stability and hepatic intrinsic clearance were in the moderate range. OSU-2S did not significantly modulate CYP enzyme activity up until 50 μM, and Caco-2 data suggested low permeability with active efflux at 2 μM. Apparent oral bioavailability in mice was 16% and 69% at 10 and 50 mg/kg, respectively. In rats, bioavailability was 24%, 35%, and 28% at 10, 30, and 100 mg/kg, respectively, while brain/plasma ratio was 36 at 6-h post-dose at 30 mg/kg. In dogs, OSU-2S was well tolerated with oral capsule bioavailability of 27.5%. Plasma OSU-2S exposures increased proportionally over a 2.5–20 mg/kg dose range. After 4 weeks of 3 times weekly, oral administration (20 mg/kg), plasma AUClast (26.1 μM*h), and Cmax (0.899 μM) were nearly 2-fold greater than those after 1 week of dosing, and no food effects were observed. The elimination half-life (29.7 h), clearance (22.9 mL/min/kg), and plasma concentrations of repeated oral doses support a 3-times weekly dosing schedule in dogs. No significant CBC, serum biochemical, or histopathological changes were observed. OSU-2S has favorable oral PK properties similar to fingolimod in rodents and dogs and is well tolerated in healthy animals. This work supports establishing trials of OSU-2S efficacy in dogs with spontaneous tumors to guide its clinical development as a cancer therapeutic for human patients.

Original languageEnglish (US)
Article number92
JournalAAPS Journal
Issue number4
StatePublished - Jul 1 2020

All Science Journal Classification (ASJC) codes

  • Pharmaceutical Science

Cite this