Today, exciting results from clinical trials testing innovative treatment ideas were presented at the Alzheimer’s Association International Conference in London. First, from the “LIBBY trial,” conducted by the NIA-funded Alzheimer’s Clinical Trial Consortium, data were presented about using THC and CBD, the psychoactive and non-psychoactive components of marijuana, as a treatment for agitation in dementia patients who are eligible for hospice care. These patients are typically residing in nursing homes and/or are nearing the end of life. No treatments currently exist for agitation in this population. The trial was a randomized, double-blind, placebo-controlled trial. THC/CBD, delivered in a novel formulation not available either for clinical or recreational use, was effective in lowering agitation scores significantly more than placebo. The results were convincing, supported by blinded clinician assessments that showed substantially more observed improvement among the active treatment than the placebo group. There were, however, more deaths in people treated with CBD/THC than there were in the placebo arm.
Separately, results were presented for Biogen’s Diranersen, a tau antisense oligonucleotide (ASO). This compound has been shown previously in a small Phase 1 trial to reduce the spread of tau tangles in the brain of people with mild Alzheimer’s disease. It is delivered by intrathecal administration, through injection into the lumbar space. Its mechanism of action is to disrupt the translation of the tau gene into the tau protein, which is the primary part of neurofibrillary tangles. The results presented at the conference were from a Phase 2 trial in a similar population as the Phase 1 study, testing three different doses of diranersen. All three doses showed large biological effects, lowering tau levels in the cerebrospinal fluid, as well as lowering tau PET. Somewhat surprisingly, the lowest dose tested (which may have had somewhat smaller biomarker effects), seemed to have the best clinical outcomes, though these too were complex. The lowest dose seemed to have a benefit on cognition, but not on function. With time, much more information will be gleaned from these exciting trials, and Phase 3 trials seem likely in the future.
