Efficacy and safety of apomorphine pump infusion in Filipino patients insufficiently controlled on oral anti-Parkinson medications: an open-label, pilot study

Background Apomorphine hydrochloride is used in the management of advanced Parkinson disease (PD), either as a rescue medication for off periods during levodopa therapy or as a maintenance pump medication. This is the first study to describe the effects of apomorphine in Filipino patients with PD. Objective To evaluate the safety and efficacy of apomorphine ampules (APO-go (R)) pump infusion in the treatment of motor fluctuations in patients inadequately controlled on oral anti-Parkinson medications. Methods Patients diagnosed with PD who developed motor fluctuations with levodopa were evaluated at baseline and at the end of the study using the Modified Hoehn and Yahr (H&Y) Scale, the Unified Parkinson's Disease Rating Scale (UPDRS) and the Abnormal Involuntary Movement Scale (AIMS). After initial assessment, patients were administered 20 ampules of apomorphine hydrochloride 10 mg/mL by infusion pump over 20 days. Intention-to-treat (ITT) analysis included all patients who completed at least one posttreatment assessment. Motor disability based on modified H&Y scores, motor function and complications of therapy pre- and posttreatment were compared using Wilcoxon Signed Rank test. Chi-squared test was used to compare outcomes by age and sex. Frequencies of adverse reactions were recorded to evaluate the tolerability of the medication. Results Ten patients (mean age 63 +/- 9.7 years), 3 male and 7 female, were enrolled in the study. Patients were given apomorphine for at most 16 days. The doses used were 2.5 mg/0.50 mL (n = 2), 3 mg/0.60 mL (n = 6), 4 mg/0.80 mL (n = 1) and 7 mg/1.40 mL (n = 1). After obtaining the threshold dose, two patients discontinued treatment. Eight of nine patients showed significant improvement in H&Y scores after treatment (p < 0.017). There was marked improvement after 10 days of treatment in at least five of 10 patients in terms of motor function using UPDRS, which included tremor (p < 0.034), rigidity (p < 0.002), facial expression (p < 0.014), finger taps (p < 0.008), foot taps (p < 0.014) and gait (p < 0.006). Significant changes from pre- to posttreatment scores in the frequency of dyskinesias (p < 0.010) and dystonia (p < 0.025) were observed. Nine focus areas of AIMS showed significant improvements in the muscles of facial expression (p < 0.020), upper (p < 0.016) and lower extremities (p < 0.010), incapacitation by abnormal movement (p < 0.010) and patients' awareness of abnormal movements (p < 0.039). Six patients experienced adverse events, none of which were related to the study drug. Conclusion Apomorphine hydrochloride pump infusion therapy is potentially effective and safe in the treatment of motor fluctuations in Filipino patients with PD. This pilot study springboards safe engagements of Filipino PD patients in multicenter, large-scale trials.