A randomized pilot trial of estrogen replacement therapy in post-menopausal women with Parkinson's disease

To assess short-term safety and tolerability of estrogen replacement therapy in post-menopausal women with Parkinson's disease (PD).

In a multi-center randomized, double-blind, placebo-controlled pilot trial, post-menopausal women with PD and motor fluctuations received either 0.625 mg/day of conjugated equine estrogens or matching placebo for 8 weeks. The primary outcome was the ability of participants to complete the trial. Other outcome measures included adverse events and changes from baseline to Week 8 in Unified PD Rating Scale scores, "on" time, dyskinesia ratings, and neuropsychological test results.

Twenty-three women (age 62.9(6.3) years, total Unified PD Rating 25.0(13.4), 8.8(6.0) years since symptom onset) were enrolled. There were no serious adverse events. One subject withdrew due to worsening of tremor and dystonia. The most commonly reported adverse events were vaginal spotting, breast enlargement and breast tenderness. The estrogen group showed improved total and motor Unified PD Rating scores although these did not reach statistical significance (mean changes from baseline, estrogen vs. placebo: Total -5.0 vs. 2.8, treatment effect = -7.8, p = 0.10; Motor -3.0 vs. 2.4, treatment effect = -5.4, p = 0.16).

Estrogen replacement therapy was safe and well-tolerated over 8 weeks in post-menopausal women with advanced PD. This pilot data suggests that estrogen replacement may be associated with improvement in motor symptoms. While larger studies of longer duration are necessary to determine the effects of estrogen in PD, the complex risk/benefit profile and continued controversy surrounding estrogen are obstacles to clinical trials.