BOSTON – The most rigorous study of its kind suggests that apomorphine subcutaneous infusion (APO) via pump can substantially reduce ‘off’ time when conventional therapy fails to control dyskinesias in patients with Parkinson’s disease.
“When a patient´s off periods start to become refractory to adjustments to their oral medication, consider continuous dopaminergic drug delivery such as subcutaneous apomorphine infusion, which has proven efficacy and is generally well tolerated in this group of patients,” lead author Regina Katzenschlager, MD, head of the department of neurology and the Karl Landsteiner Institute for Neuroimmunological and Neurodegenerative Disorders at Danube Hospital in Vienna, said in an interview.
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According to the study authors, previous open-label research has supported the use of apomorphine to reduce dyskinesias, off time, and the need for levodopa.
For the new study, researchers recruited 106 patients aged at least 30 years with a diagnosis of idiopathic Parkinson’s disease and motor fluctuations that were not adequately controlled by medication. They all were taking L-dopa and had an average off time of at least 3 hours a day.
The subjects, who came from 23 centers in seven countries, were randomly assigned to receive apomorphine infusion while they were awake (16 hours; 8 or less mg/hour) or placebo saline infusion.
“Apomorphine is administered via bespoke pumps, which are produced by several manufacturers,” Dr. Katzenschlager said. “The pump used in the trial is a mechanical delivery system and has been in clinical use in Europe for many years for this purpose. The pump is worn outside the body; no surgical procedure is required. It delivers the drug continuously into the subcutaneous fatty tissue, usually abdomen or thighs, via a tube and a thin metal or Teflon needle.”
The pump is about the size of a mobile phone, Dr. Katzenschlager said, and typically worn in a pouch attached to a belt.
The study abstract does not note the dose of apomorphine, and Dr. Katzenschlager declined to say how much of the drug is given to patients. The trial information on clinicaltrials.gov states only that a 5-mg/mL solution of APO-go was to be provided via prefilled syringe. The hourly flow rate of apomorphine and dosages of other Parkinson’s disease medications were adjusted during the first 4 weeks of the trial for efficacy and tolerability purposes.
Researchers report that daily off time declined over the 12-week trial (–0.58 hours for placebo vs. –2.47 hours for apomorphine), accounting for a difference of –1.89 hours (95% CI, –3.16 to –0.62; P = .0025).
“This was highly statistically significant. This degree of improvement has been proven to be clinically relevant to the patients,” Dr. Katzenschlager said. “This was reflected in the patients’ own assessment of the overall treatment effect in the study.”
The study examined Patient Global Impression of Change in apomorphine vs. placebo. The abstract released at the AAN meeting does not report the full results but says that the apomorphine patients had higher scores at the end of the study (P less than .001).
Why might this infusion approach work? “Apomorphine infusion achieves more than injections, which are intended as a rescue therapy for off periods in addition to the patients’ oral medication,” Dr. Katzenschlager said. “The continuous delivery of apomorphine resembles the natural state of dopamine levels in the brain in persons without Parkinson’s disease, where this is mostly stable. The administration via the pump system usually enables oral drugs to be reduced. This may contribute to the improvement in dyskinesias often observed and is a benefit to the patients in itself.”
The study authors noted that apomorphine “was generally well tolerated and no unexpected adverse events were observed.” Dr. Katzenschlager declined to discuss cost.
Britannia Pharmaceuticals, which manufactures APO-go, funded the study. Dr. Katzenschlager reports multiple disclosures, including research support and speaking/consulting fees from Brittania Pharmaceuticals.