BOSTON – The results of a small phase II trial confirm that IPX203, an investigational reformulation of the extended-release carbidopa-levodopa combination called Rytary, holds the potential to greatly extend “on” time in Parkinson’s disease patients.
While it’s early in the research process, “this is a promising new formulation,” said Mark Stacy, MD, who led the trial that pitted IPX203 against immediate-release (IR) carbidopa-levodopa (CD-LD) and Rytary.
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Dr. Stacy, professor of neurology and vice dean for clinical research at Duke University, Durham, N.C., and his colleagues released the phase II results at the annual meeting of the American Academy of Neurology.
Parkinson’s disease patients often aren’t adherent to their drugs despite the risk that they’ll see symptoms return. “It’s been demonstrated that they miss medicines as often as in any other disease,” Dr. Stacy said in an interview.
Rytary, which was approved by the Food and Drug Administration in 2015, has improved adherence in Parkinson’s disease patients by allowing them to reduce the number of doses they need to separately take every day to four. “If this new formulation is able to last 8 hours, you could essentially take that at bedtime and have medication in your system when you awaken,” Dr. Stacy said. “Then you could take it twice more during the day.”
The new, open-label, crossover trial randomly assigned 26 patients on stable IR regimens (at least 400 mg LD/day, at least 4 doses a day) to single doses of IR, Rytary, and IPX203. For 10 hours after dose, raters evaluated every 30 minutes whether the subjects were on (with troublesome dyskinesia) or off (without troublesome dyskinesia).
All but one subject finished the trial. Over the first hour, the patients fared about the same in terms of converting to on status. Overall, PX203 significantly decreased average off time (4.5 hours), compared with IR (7.2 hours; P less than .0001) and Rytary (5.4 hours; P less than .05).
Researchers also found that IPX203 had the highest duration of a 4-point improvement in the Unified Parkinson’s Disease Rating Scale Part III score at 6.1 hours, compared with IR (3.7 hours; P less than .0001) and Rytary (5.2 hours; P less than .05). In addition, 13-point improvements were higher for IPX203 at 4.8 hours, compared with IR (2.2 hours; P less than .0001) and Rytary (3.6 hours; P less than .05).
No serious adverse events were reported. Nausea, dizziness, and hypertension occurred in two or more patients in each treatment group and were more common with IR (28.0%) and IPX203 (19.2%) than with Rytary (8.0%).
The study was funded by Impax Laboratories. Dr. Stacy reported several disclosures, including consulting work for numerous drug makers.