Alzheimer’s pill lowers blood marker but misses trial’s main goal

An experimental Alzheimer’s pill failed to meet its main goal of slowing decline in memory and thinking across the trial population. Yet the drug, valiltramiprosate, lowered a blood measurement linked to the disease, particularly in people with milder symptoms. Drugs (source, opens in new tab)

The researchers measured p-tau217, a form of the protein tau linked to Alzheimer’s-related changes in the brain. Tracking its level in blood helps them investigate whether a treatment is affecting the disease’s biology. To find out whether those changes actually help patients, researchers must also test their memory, thinking and ability to manage everyday tasks.

Everyone in the trial carried two copies of APOE4, a genetic variant that increases Alzheimer’s risk. The clearest blood result came from those with mild cognitive impairment: memory or thinking problems that had not reached the severity of dementia. After 78 weeks, their p-tau217 levels had fallen by 36% on the drug, while rising by 17% on placebo—a pill without the active drug.

The trial’s main test compared the drug with placebo across all participants. The researchers also examined differences among people with milder symptoms who received the drug. Those whose p-tau217 levels fell more tended to experience less decline in memory, thinking and everyday abilities, and less loss of brain volume. These changes occurred together, but that does not establish that one caused the other—or show how those same people would have fared without treatment. Alzheon (source, opens in new tab)

The researchers compared changes in the blood marker with several measures of memory, everyday abilities and brain structure. The more comparisons researchers make, the greater the chance that some will appear convincing even if they reflect random variation. The analysis did not account for this, so some of the reported connections could be chance findings. Blood samples were also unavailable for some participants, leaving uncertainty about whether the missing results would change the picture.

The study, sponsored by the drug’s developer, Alzheon, offers a clue about how to track a treatment’s effects. Whether the pill can help people at this earlier stage preserve their memory and independence remains unresolved.

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