For families facing a rare, inherited form of Alzheimer's, even a hint that a treatment could work matters. This small, early study tested etalanetug, an experimental drug given by IV, in eight people with memory and thinking problems from this condition. Researchers first checked for safety and to see if the drug was affecting the target.
Over about two years, the drug appeared to lower two key tau proteins in spinal fluid—ptau217 and MTBR-tau243—with bigger drops the longer people took it. Brain scans (tau PET) were mostly stable, and one measure showed no new tau buildup in three people scanned at the end. Three people had treatment-related side effects with a higher dose, and there were five serious side effects overall.
This study is very small, had no control group, and had missing data at later time points, so we can't know if these biomarker changes mean real-world benefits. Early studies like this are about testing an idea, not proving a drug works.
