The AMBAR study analyzed the effects of plasma exchange (PE) with albumin (with or without intravenous immunoglobulin, IVIG) on mild-to-moderate Alzheimer’s disease (AD) patients. Of the 496 patients enrolled, 347 were randomized into three treatment groups (different doses of albumin and IVIG) and a placebo group. Results showed that PE slowed cognitive and functional decline in AD patients, with consistency across various outcomes like ADCS-ADL, ADAS-Cog, and CDR-Sb.
Key Findings:
- Dropout rates ranged from 20% (placebo) to 34.9% (low-albumin+IVIG). Analysis indicated that dropouts likely had a conservative effect on the treatment’s effectiveness, suggesting that reducing dropouts could increase effect sizes.
- The treatment effect sizes ranged from 51% to 76% across outcomes, demonstrating consistency.
- A Global Statistical Test (GST) combining multiple outcomes showed significant slowing of disease progression in PE-treated groups compared to placebo from month 9 onward.
- Adjusting for baseline characteristics confirmed that all treatment groups significantly outperformed the placebo in most outcomes.
Conclusion: This analysis indicates that the effects observed in the AMBAR trial are not biased by dropouts. The consistency across outcomes and adjusted analyses further supports the efficacy of PE with albumin and IVIG in slowing AD progression compared to placebo.