Phase 3 Study Results Compare IPX203 to Immediate-Release Carbidopa/Levodopa for PD

IPX203 demonstrated statistically significant improvement in daily “Good On” time compared to optimised IR CD/LD, with fewer daily doses

August 24th, 2023: Amneal Pharmaceuticals, Inc announced that JAMA Neurology has published results from the RISE-PD clinical study assessing the efficacy and safety of IPX203 versus optimised immediate-release carbidopa/levodopa (IR CD/LD) for the treatment of Parkinson’s disease (PD). The study met its primary and secondary endpoints finding that IPX203 provided more hours of “Good On” time per day, less “Off” time per day, and more “Good On” time per dose than optimised IR CD/LD, even when dosed less frequently. “Good On” time is defined as the sum of “On” time without dyskinesia and “On” time with non-troublesome dyskinesia. The manuscript titled, “IPX203 vs Immediate-Release Carbidopa-Levodopa for the Treatment of Motor Fluctuations in Parkinson Disease,” was published online on August 14, 2023.

When it comes to Parkinson’s disease, the community is looking for treatments that provide a longer duration of benefit per dose of LD and simplified dosing regimens. We are very encouraged by the recently published data in JAMA Neurology which illustrate how IPX203 could fill this need, potentially leading to a better patient experience, more ‘Good On’ time, and improved patient adherence.

Robert A. Hauser, M.D., Professor of Neurology at the University of South Florida and Director of the Parkinson’s Disease and Movement Disorders Center.

Following a Complete Response Letter (CRL) from the FDA earlier this year on its New Drug Application for IPX203, Amneal has shared a reanalysis of the data and requested a Type A meeting as it looks to bring the treatment to market.

About the RISE-PD Trial

The multicenter, randomised, double-blind, double-dummy, active-controlled, parallel-group RISE-PD trial evaluated the efficacy and safety of IPX203 CD/LD extended-release capsules compared with IR CD/LD in the treatment of patients with PD who have motor fluctuations.

The trial consisted of a 3-week, open-label immediate-release CD/LD dose adjustment period and a 4-week, open-label period for conversion to IPX-203. This was followed by a 13-week double-blind treatment period in which patients were randomised 1:1 to receive either IPX203 (with matching immediate-release CD/LD placebo) optimised IR CD/LD (with matching IPX-203 placebo). Baseline for all endpoints was Week 7 (Visit 4), which occurred pre-randomisation. The most common adverse reaction (incidence ≥ 3% and greater than immediate-release CD/LD) was nausea (4.3%).

The primary endpoint of the trial assessed the change from baseline in “Good On” time in hours per day at the end of the double-blind treatment period (Week 20 or early termination). “Good On” time is defined as the sum of “On” time without dyskinesia and “On” time with non-troublesome dyskinesia. Secondary endpoints assessed the change from baseline in “Off” time in hours per day, proportion of patients who were either “much improved” or “very much improved” in Patients’ Global Impression of Change (PGI-C) scores, change from baseline in the Movement Disorder Society – Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) Part III score, and the change from baseline in sum of MDS-UPDRS Parts II and III scores.

The trial was conducted at 105 clinical sites in the U.S. and European countries, including Czechia, France, Germany, Italy, Poland, Spain and the United Kingdom. The study randomised 506 patients who had received a PD diagnosis at age 40 or older. The study design was reviewed by the FDA and conducted pursuant to a Special Protocol Assessment. A nine-month safety extension study was completed in 2022.