Common blood pressure drug does not slow down the progression of Alzheimer’s Disease
Monday, December 20th, 2021
New research has dashed hopes that the drug Losartan, used to treat hypertension or high blood pressure, might be effective in reducing the rate of brain atrophy in people living with Alzheimer’s Disease.
The British multi-centre clinical trial was awarded two million pounds as part of the Prime Minister’s “Challenge on Dementia”. From 2014 to 2018, the study recruited adults aged 55 years or older who had been diagnosed with mild to moderate Alzheimer’s Disease, and had never been prescribed similar angiotensin receptor blocker drugs. People could participate regardless of whether they had hypertension or whether they were taking dementia medication or other, unrelated, blood pressure medication.
The 211 eligible participants were randomly allocated to receive either 100mg of losartan, or an identical looking placebo pill with no active ingredients. Participants took the pill once a day, for 12 months. Outcome data were available for 171, or 81%, of participants. The study was of high scientific standard in that it was “double-blind”. This means that neither the participants, nor the doctors, knew which tablet the participants were taking.
The trial assessed disease progression as the rate of whole brain shrinkage or atrophy on an MRI scan. The researchers also implemented tests of memory and day-to-day quality of life, as well as changes in vascular or blood vessel damage in a subgroup of participants. The team found no significant differences between those prescribed the hypertension drug and the placebo; this was despite the drug clearly doing its job in reducing blood pressure for those taking losartan.
The study commenced when dementia biomarkers were still in their infancy or prohibitively expensive, so it missed out on a more definite selection of participants. Further, the study does not rule out that the drug could still be of benefit if prescribed for longer than the study’s twelve months. It could also be that the drug is effective if given to people earlier in the course of their Alzheimer’s disease; for example, when signs of mild cognitive impairment first start to show. But for now, we continue to wait for a drug to pin our hopes on.