Tau-targeting oral therapy falls short in early Alzheimer’s disease

Clinical takeaway: Ceperognastat should not be considered an effective disease-modifying therapy for early symptomatic Alzheimer disease based on current evidence; the drug failed to improve clinical outcomes and higher-dose treatment was associated with worse progression and more adverse events.

With growing interest in therapies that target tau pathology beyond amyloid, these results highlight the challenge of translating biomarker effects into meaningful clinical benefit for patients with Alzheimer disease.

In the phase 2 PROSPECT-ALZ trial, investigators evaluated ceperognastat, an oral O-linked N-acetylglucosaminidase (OGA) inhibitor designed to reduce tau-related pathology, in 327 adults with early symptomatic Alzheimer disease across 72 sites in five countries. The primary analysis included 259 participants with low to medium baseline tau burden on PET imaging.

After 100 weeks, the study missed its primary endpoint. Decline on the Integrated Alzheimer’s Disease Rating Scale was similar to placebo with the 0.75-mg dose and worse with the 3-mg dose. Compared with placebo, the lower dose was associated with an estimated 16% less clinical progression, while the higher dose was linked to 32% greater progression, failing to meet prespecified criteria for success. No meaningful benefits were seen across key secondary measures of cognition, function, or global disease severity.

Investigators did observe selected biomarker signals. The 3-mg dose was associated with a smaller increase in tau PET signal in one temporal lobe region, and both treatment groups showed about 43% to 50% less whole-brain volume loss on MRI versus placebo. However, these imaging findings did not translate into better clinical outcomes.

Safety also raised concerns. Serious treatment-emergent adverse events occurred in 26% of participants receiving 3 mg of ceperognastat versus 16% with placebo, while severe adverse events were reported in 14% and 7%, respectively.

Source: Fleischer AS, et al. (2026 July 13) JAMA. Ceperognastat in Early Symptomatic Alzheimer Disease: A Randomized Clinical Trial