First results from young blood Alzheimer’s trial are criticised

The long-awaited results of a trial involving the injection of blood from young people as a treatment for Alzheimer’s disease have been met with criticism.

In 2014, a team led by Tony Wyss-Coray at Stanford University received approval to inject young human blood plasma into older people with Alzheimer’s. Young mouse blood had improved the physical and cognitive function of older mice, prompting Wyss-Coray to found the firm Alkahest. Results were finally presented at a summit on clinical trials for Alzheimer’s in Boston this week.

The trial suggests treatment with young plasma – mostly from people aged 18 to 25 – does have potential effects on Alzheimer’s symptoms, says Karoly Nikolich of Alkahest. He says improvements were seen in mental skills and the ability to do daily activities. “They had more awareness of self and their surroundings,” says Nikolich.

Placebo problems

Initially, the plan was to give one group the treatment and another a placebo of saline, and have them swap places after a number of weeks. However, several people dropped out, says Nikolich.

So a new trial was begun that included no placebo group, just weekly injections of plasma for four weeks. To assess its effects, the team used placebo data from the original version of the trial, says Nikolich.

This may make the results unusable, says Michael Conboy at the University of California, Berkeley. “It’s like picking all the aces out of a deck of cards and then shuffling the deck.”

Nikolich says that weekly questionnaires completed by caregivers showed real, objective improvements in participants’ abilities in daily life. But Conboy says the study design makes the results nearly irrelevant. “The caregivers will flag up any slightest change as indicating that the treatment is working,” he says.