Inhibikase Therapeutics, Inc. announced a publication of Phase 1 clinical studies with risvodetinib (risvo), a potential disease-modifying therapy for Parkinson?s disease and related disorders. The publication entitled ?A Phase I, Randomized, SAD, MAD, and PK Study of Risvodetinib in Older Adults and Parkinson?s Disease? was published online in the peer reviewed Journal of Parkinson?s Disease (DOI: 10.3233/JPD-230319) on January 13, 2024.

The publication highlights the safety, tolerability and pharmacokinetics of risvo in 94 healthy volunteers and 14 participants with Parkinson?s disease. The multi-part study evaluated risvo in both single ascending dose (SAD) and multiple ascending dose (MAD) studies. Older and elderly healthy participants, aged 45 to 70, in the SAD portion of the study received single doses ranging from 12.5 to 325 mg, while participants in the MAD portion received daily doses between 25 and 200 mg for seven days.

In addition, participants with Parkinson?s disease who remained on a stable regimen of anti-PD medications were evaluated in the MAD study at either 50 or 100 mg once daily for seven days. Risvo demonstrated a favorable safety and tolerability profile following both single or multiple doses across all trial participants. Only 11 of the observed adverse events were deemed possibly treatment-related, with none of clinical significance.

Single dose pharmacokinetics were approximately linear between 12.5 mg and 200 mg for both Cmax and AUC0-inf with no pharmacokinetic difference between healthy volunteers and participants with PD. Exposures at each dose were high relative to other drugs in the same kinase inhibitor class. Of note, voluntary lumbar puncture was used to measure the concentration of risvo in cerebrospinal fluid (CSF) in six participants with or without PD.

In these participants, risvo was measured in the cerebrospinal fluid just before dosing on the 7th day, when the concentration of risvo would be at steady-state trough. Measures of the CSF concentration of risvo at trough indicated that risvo crossed the blood-brain barrier and was persistently present in the central nervous system. The concentration of risvo in the brain could not be determined from these measurements in the absence of a brain biopsy.

Inhibikase continues to actively enroll patients in its Phase 2 201 Trial, evaluating risvo in untreated Parkinson?s disease. As of January 29, 2024, 32 sites are open and actively evaluating prospective trial participants. 45 participants have been enrolled, 18 prospective participants are in medical screening and 54 potential participants are being evaluated for suitability to initiate medical screening.

19 participants have completed the 12 week dosing period. To date, only seven mild and one moderate adverse event that could possibly have arisen as a result of taking risvo have been reported across all enrolled patients.