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Extended-Release Drug May Provide New Treatment Option for Parkinsonís

A new extended-release formulation of carbidopa-levodopa has been shown in a Phase III clinical trial to decrease “off time” in people with Parkinson’s disease (PD), when compared with the standard immediate-release form of the drug. The results appear in the February 26 online edition of The Lancet Neurology.

Carbidopa-levodopa, usually taken as Sinemet®, is the gold standard therapy for the movement symptoms of PD. After taking the drug for several years, however, many people with PD experience “off” times — times in between doses when the medication’s effects have worn off and movement symptoms return. 

The experimental drug, known as IPX066, is a capsule containing beads of carbidopa and levodopa. Some of the beads are released quickly and others dissolve at various rates, to help maintain a steady level of the drugs in the body over time. 

Researchers led by Robert A. Hauser, M.D., at the University of South Florida, recruited more than 400 people with PD to participate in the study at 68 centers in the United States and Europe. On average, study participants were 63 years old, had been diagnosed with PD for seven years, and experienced about six hours of daily off-time while taking standard, immediate-release carbidopa-levodopa. 

Dr. Hauser and colleagues first determined optimum dosages of both the standard and experimental drugs for each participant. Then, of the participants who continued with the study, 192 received regular carbidopa-levodopa and 201 received IPX066 for 13 weeks. The study was double-blind, meaning that neither participants nor researchers knew who was taking which medication. 


  • On average, people taking the experimental medication, IPX066 had about an hour less off-time during the day, as recorded in their diaries.
  • People taking IPX066 also experienced more on-time without troublesome dyskinesia.
  • For those taking IPX066, fewer doses were needed throughout the day — three or four, versus five or six for the standard therapy.
  • For those taking IPX066, a higher equivalent dosage of levodopa was needed to get the optimum benefit from IPX066 compared with the immediate-release form.
  • Overall, IPX066 appeared to better manage PD movement symptoms as assessed using a standard measurement scale (the UPDRS).
  • The most common side effects of IPX066 were insomnia and nausea.

What Does It Mean?

Levodopa is an excellent treatment for the motor symptoms of PD. Unfortunately, as the disease progresses, many people require to take the medication more frequently during the day, and the effect may not last as long. Doctors may increase the “on” time, the hours a day levodopa works efficiently, by adjusting carbidopa-levodopa dosage and schedule, or by adding other medications. These can include monoamine oxidase-B inhibitors  - such as rasagiline (Azilect®) and selegiline (Eldepryl®) and dopamine agonists (for example, pramipexole (Mirapex®)or ropinirole (Requip®)), or entacapone (Comtan®). 

Sinemet®, the standard carbidopa-levodopa therapy, already is available in a controlled-release version (Sinemet CR®). However, because it releases levodopa into the body gradually, it may take effect more slowly than conventional Sinemet®. IPX066 was formulated to address this issue by containing some medication that is rapidly released.  

If and when this drug is available, IPX066 will provide another tool for people with Parkinson’s disease and their doctors. Future research will be needed to compare its benefits to those of non-levodopa drugs with respect to off-time

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Reference: Robert A Hauser, Ann Hsu, Sherron Kell, Alberto J Espay, Kapil Sethi, Mark Stacy, William Ondo, Martin O'Connell, Suneel Gupta. (2013) Extended-release carbidopa-levodopa (IPX066) compared with immediate-release carbidopa-levodopa in patients with Parkinson's disease and motor fluctuations: a phase 3 randomised, double-blind trial. The Lancet Neurology, 12(4):346-356. 10.1016/S1474-4422(13)70025-5.

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Source Date: Apr 09 2013