, according to a new study. The beneficial effects of these phosphate prodrugs of levodopa and carbidopa were most noticeable in the early morning, results of the phase 1B study showed.
As Parkinson’s disease progresses and dosing of oral levodopa/carbidopa (LD/CD) increases, its therapeutic window narrows, resulting in troublesome dyskinesia at peak drug levels and tremors and rigidity when levels fall.
“Foslevodopa/foscarbidopa shows lower ‘off’ time than oral levodopa/carbidopa, and this was statistically significant. Also, foslevodopa/foscarbidopa (fosL/fosC) showed more ‘on’ time without dyskinesia, compared with oral levodopa/carbidopa. This was also statistically significant,” lead author Sven Stodtmann, PhD, of AbbVie GmbH, Ludwigshafen, Germany, reported in his recorded presentation at the Movement Disorders Society’s 23rd International Congress of Parkinson’s Disease and Movement Disorder (Virtual) 2020.
Continuous infusion versus oral therapy
The analysis included 20 patients, and all data from these individuals were collected between 4:30 a.m. and 9:30 p.m.
Participants were 12 men and 8 women, aged 30-80 years, with advanced, idiopathic Parkinson’s disease responsive to levodopa but inadequately controlled on their current stable therapy, having a minimum of 2.5 off hours/day. Mean age was 61.3 plus or minus 10.5 years (range 35-77 years).
In this single-arm, open-label study, they received subcutaneous infusions of personalized therapeutic doses of fosL/fosC 24 hours/day for 28 days after a 10- to 30-day screening period during which they recorded LD/CD doses in a diary and had motor symptoms monitored using a wearable device.
Following the screening period, fosL/fosC doses were titrated over up to 5 days, with subsequent weekly study visits, for a total time on fosL/fosC of 28 days. Drug titration was aimed at maximizing functional on time and minimizing the number of off episodes while minimizing troublesome dyskinesia.
Continuous infusion of fosL/fosC performed better than oral LD/CD on all counts.
“The off time is much lower in the morning for people on foslevodopa/foscarbidopa [compared with oral LD/CD] because this is a 24-hour infusion product,” Dr. Stodtmann explained.
The effect was maintained over the course of the day with little fluctuation with fosL/fosC, off periods never exceeding about 25% between 4:30 a.m. and 9 p.m. For LD/CD, off periods were highest in the early morning and peaked at about 50% on a 3- to 4-hour cycle during the course of the day.
Increased on time without dyskinesia varied between about 60% and 80% during the day with fosL/fosC, showing the greatest difference between fosL/fosC and oral LD/CD in the early morning hours.
“On time with nontroublesome dyskinesia was lower for foscarbidopa/foslevodopa, compared to oral levodopa/carbidopa, but this was not statistically significant,” Dr. Stodtmann said. On time with troublesome dyskinesia followed the same pattern, again, not statistically significant.
Looking at the data another way, the investigators calculated the odds ratios of motor symptoms using fosL/fosC, compared with oral LD/CD. Use of fosL/fosC was associated with a 59% lower risk of being in the off state during the day, compared with oral LD/CD (odds ratio, 0.4; 95% confidence interval, 0.2-0.7; P < .01). Similarly, the probability of being in the on state without dyskinesia was much greater with fosL/fosC (OR, 2.75; 95% CI, 1.08-6.99; P < .05).