A randomized, double-blind, controlled trial of add-on therapy in moderate-to-severe Parkinson's disease

The primary objective was to evaluate the efficacy and safety of droxidopa as add-on therapy in improving stiffness, tremors and other motor functions and activities of daily living for moderate-to-severe Parkinson's disease (PD).

PD patients, above Hoehn-Yahr III (including Hoehn-Yahr III), were randomly assigned to drug therapy (droxidopa 600 mg/day for 8 weeks) or placebo. Efficacy indicators were the Unified Parkinson's Disease Rating Scale (UPDRS) part I, II, III subscale, Clinical Global Impression (CGI) rating score, and individual symptom scores (e.g. stiffness, tremors), to evaluate motor function and activities of daily life.

There are 109 patients in the droxidopa group, and 110 in the placebo group, at baseline, there were no differences between the two groups for age, body weight, disease severity and previous drugs therapy. At days 14 and 57 of droxidopa add on treatment, UPDRS-II scores reflecting activities of daily life and UPDRS-III scores reflecting motor functions were significantly different compared to the pre-treatment baseline scores (P < 0.01), UPDRS- II and UPDRS-III scores at day 14 and day 57 were also significantly different (P < 0.01) between the two groups. Individual motor symptoms such as stiffness, resting tremor, and alternate hand motion were also significantly improved with droxidopa on days 14 and 57 of treatment (P < 0.01 vs placebo), showing that droxidopa is effective in improving rigidity, tremor and alternate motion of hand.

Droxidopa was effective as symptomatic adjunct therapy, improved significantly motor function and activities of daily living, benefited patients with signs of tremor and Stiffness.