Alnylam said its experimental Huntington’s therapy brezosiran showed target engagement and “encouraging” safety signals in a small study, with plans to move toward proof in a placebo-controlled trial. The company presented new data at the European Huntington’s Disease Network Clinical Research Congress. In patients receiving brezosiran, those on the highest dose levels saw mutant huntingtin levels in spinal fluid fall by about 60% to 64% on average across assay types. Alnylam framed the results as high knockdown with tolerable side effects. The company’s R&D next step is a placebo-controlled study designed to determine whether biochemical knockdown translates into slowing disease progression, a key bar for gene-silencing programs in Huntington’s. The dataset is early, but it strengthens the case for continued clinical development of RNA therapeutics in neurodegeneration.