Phase 2 trial of risvodetinib for Parkinson’s now fully enrolled

201 trial testing safety, efficacy of oral therapy in untreated patients

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by Andrea Lobo |

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An illustration features the word Enrollment in black letters with Complete in red letters and underlined just below it.

Patient enrollment is now complete in a Phase 2 trial that’s assessing the safety and efficacy of oral risvodetinib, being developed by Inhibikase Therapeutics to slow or stop the progression of Parkinson’s disease.

The 201 trial (NCT05424276) has enrolled 120 participants across 32 sites in the U.S., and expects to involve 126 patients, this way not to exclude already screened participants from the trial. To date, 69 patients have completed dosing, with a total of 32 mild and five moderate adverse events potentially related to the treatment reported.

Previously reported data from 25 patients who completed dosing demonstrated that risvodetinib appeared to stabilize disease progression and symptom severity. Inhibikase expects to report top-line data later this year, according to a company press release.

“The completion of enrollment for the 201 Trial in untreated Parkinson’s disease represents a major milestone for Inhibikase,” said Milton H. Werner, PhD, Inhibikase’s president and CEO.  “We look forward to reporting trial results in the fourth quarter, and the discussion with the FDA on our plans for pivotal Phase 3 trials by the end of the year.”

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Patients receiving 50-200 mg risvodetinib dose or placebo in Phase 2 trial

Risvodetinib, previously known as IkT-148009, is an oral small molecule that blocks the activation of Abelson tyrosine kinase, an enzyme involved in multiple cellular processes and a known target for the treatment of Parkinson’s.

By blocking this enzyme, risvodetinib helps restore protective mechanisms in the brain and gastrointestinal tract, which is expected to prevent the loss of dopaminergic neurons — dopamine-producing nerve cells — and to slow or stop Parkinson’s progression. Dopamine is a neurotransmitter that plays a role in many bodily functions, including movement, memory, and mood.

Eligible patients for the study included those who had never received and were not planning to start treatments to control Parkinson’s symptoms, but who displayed bradykinesia, or slowness of movements, an early sign of the disease.

Participants are randomly assigned to receive risvodetinib, given as a gelatin capsule once daily at a 50, 100, or 200 mg dose, or a placebo, for 12 weeks, or about three months. After completing the trial, patients are eligible to enter a one-year extension study, in which those in the placebo group will receive the treatment at its highest daily dose.

The trial’s main goal is to assess the incidence and severity of adverse events, or side effects, and understand if they are related to the treatment. The study also is evaluating the proportion of patients who discontinue the treatment in each group.

Secondary outcomes include treatment efficacy at easing disease symptoms, assessed by analyzing changes in patients’ motor and nonmotor function. That evaluation is done using the Movement Disorder Society-sponsored revision of the Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) parts 1 to 3.

[This] achievement reflects the hard work of our team, the success of our proprietary and innovative patient identification and referral service and the commitment of our 32 U.S. study sites to evaluating potential disease-modifying solutions for patients with this debilitating disease.

Other measurements include patient and clinical global impression of disease severity, and further assessments of motor, nonmotor, and gastrointestinal function.

According to Werner, the company’s “achievement reflects the hard work of our team, the success of our proprietary and innovative patient identification and referral service and the commitment of our 32 U.S. study sites to evaluating potential disease-modifying solutions for patients with this debilitating disease.”

The trial was put on a two-month clinical hold by the U.S. Food and Drug Administration due to safety concerns related to the higher treatment dose of 200 mg. The hold was lifted after the company provided data on the treatment’s safety and pharmacological properties.

An analysis of 11 patients, enrolled before the trial hold, showed that the combined MDS-UPDRS parts 2 and 3 scores decreased by 8.7 points in those given the higher dose, while it increased by 1.7 points in patients receiving the placebo or the 50 mg dose. Risvodetinib reached steady levels in the body after up to five days.

A previous Phase 1 trial (NCT04350177) testing single and multiple ascending risvodetinib doses in healthy adults and Parkinson’s patients found the treatment was safe and well tolerated, with no serious side events reported.