Alzheimer’s disease affects 55 million people worldwide, a number projected to triple by 2050, according to recent health reports. Despite decades of research and billions invested in treatment development, approved therapies offer only marginal benefits to patients.
The limited progress stems largely from the long-dominant amyloid hypothesis, which posits that beta-amyloid plaque accumulation in the brain is the primary cause of Alzheimer’s. However, multiple drugs designed to clear these plaques have failed to significantly improve patient cognition in clinical trials.
In 2025, Roche presented trontinemab, an antibody that removed 91% of amyloid plaques in Phase Ib/IIa trials, with reduced side effects including ARIA-E occurring in less than 5% of cases. Whereas promising, this approach remains focused on amyloid, even as the field begins diversifying toward alternative targets like the tau protein and neuroinflammation.
Research indicates that tau pathology correlates more strongly with symptom severity than amyloid buildup, making anti-tau therapies a potentially more effective strategy once cognitive decline has begun. Early anti-tau drug development focused on modifying tau after it’s produced, preventing its aggregation and stabilizing microtubules that support neuron structure.
Recent setbacks have tempered optimism in this area. Johnson & Johnson halted development of its Alzheimer’s antibody posdinemab after it failed to meet primary endpoints in a Phase 2b trial, dealing a blow to hopes that anti-tau treatments could soon emerge as viable options.
Current Alzheimer’s clinical trials now enroll thousands of participants across multiple countries, but the average cost to develop a single drug for the disease exceeds $2 billion. Experts say this high financial barrier, combined with repeated trial failures, has slowed innovation in the space.
The growing global burden of Alzheimer’s underscores the urgent need for new diagnostic tools and treatment approaches. Early detection enabled by artificial intelligence, alongside exploration of mechanisms beyond amyloid, is opening fresh opportunities for health technology startups and researchers aiming to address this expanding public health challenge.
