Objective: To use a historical placebo control design to determine whether lithium carbonate slows progression of amyotrophic lateral sclerosis (ALS).Methods: A phase II trial was conducted at 10 sites in the Western ALS Study Group using similar dosages (300-450 mg/day), target blood levels (0.3-0.8 mEq/L), outcome measures, and trial duration (13 months) as the positive trial. However, taking riluzole was not a requirement for study entry. Placebo outcomes in patients matched for baseline features from a large database of recent clinical trials, showing stable rates of decline over the past 9 years, were used as historical controls.
Results:The mean rate of decline of the ALS Functional Rating Scale-Revised was greater in 107 patients taking lithium carbonate (Ϫ1.20/month, 95% confidence interval [CI] Ϫ1.41 to Ϫ0.98) than that in 249 control patients (Ϫ1.01/month, 95% CI Ϫ1.11 to Ϫ0.92, p ϭ 0.04). There were no differences in secondary outcome measures (forced vital capacity, time to failure, and quality of life), but there were more adverse events in the treated group.
Conclusions:The lack of therapeutic benefit and safety concerns, taken together with similar results from 2 other recent trials, weighs against the use of lithium carbonate in patients with ALS. The absence of drift over time and the availability of a large database of patients for selecting a matched historical control group suggest that use of historical controls may result in more efficient phase II trials for screening putative ALS therapeutic agents.
Classification of evidence:This study provided Class IV evidence that lithium carbonate does not slow the rate of decline of function in patients with ALS over 13 months. Neurology ® 2011;77:973-979 GLOSSARY ALS ϭ amyotrophic lateral sclerosis; ALSFRS-R ϭ ALS Functional Rating Scale-Revised; CI ϭ confidence interval; FVC ϭ forced vital capacity; MINO ϭ minocycline in ALS trial; NSAE ϭ nonserious adverse event; QOL ϭ quality of life; SAE ϭ serious adverse event; WALS ϭ Western ALS Study Group.