The 10th annual Clinical Trials on Alzheimer's Disease meeting, which took place earlier this month in Boston, has marked bittersweet conclusion as medical experts experience failed trials, while a few new trials seem promising.

“We are trying to treat and prevent dementia,” said Dr Maria Carrillo, chief science officer at the Alzheimer’s Association. “This may very well be one of the most difficult things that science and medicine is trying to do in this century.”

While challenges remain to be the case for Alzheimer’s research, Stanford University presented good news.

Young blood to breathe new life into seniors

Researchers from Stanford University School of Medicine reported success in an early-phase clinical trial that examines the safety, permissibility and practicality of administering infusions of blood plasma from young donors to patients with mild to moderate Alzheimer's disease.

The researchers studied 18 patients and aimed at determining whether human plasma had any ill-effects on patients. The result not only showed few side effects – itching was observed in the experiment, but showed improvements in functions like remembering medications.

“We thought it would be safe and it is,” said Dr Sharon Sha. “What’s really exciting is that in such a short period of time we found an improvement in functional ability.”

The PLasma for Alzheimer's Symptom Amelioration (PLASMA) study was intended to test a hypothesis originated by Tony Wyss-Coray, PhD, Stanford professor of neurology and neurological sciences and a senior research career scientist at the Veterans Affairs Palo Alto Health Care System. His research showed that factors in the blood of young mice “can counteract and reverse pre-existing effects of brain aging” in older mice.

“I’m excited to see that giving repeated infusions of plasma to elderly people with Alzheimer’s disease is safe and that we can move forward to larger studies,” shared Wyss-Coray. “But, I’m also realistic enough to know that it is very easy to cure diseases in small animals and a million times more difficult in humans.”

In another similar study done on mice, SAPHIR trial reported Probiodrug‘s PQ912 decreases markers of inflammation and damage in the nerve cell connections of Alzheimer’s patients. Researchers from VU University Medical Centre in Amsterdam found high levels of the glutaminylcyclase enzyme in the brains of Alzheimer’s patients. PQ912 inhibits the enzyme. The study using mouse models of the disease showed that PQ912 improved the animals’ cognition.

Ongoing trials hope to secure favourable results

PLASMA trial and SAPHIR trial is not the only promising news presented at CTAD. Biogen’s injectable aducanumab presented long-term result. Biogen’s result reveals that after three years, there were no signs of amyloid, the toxic plaque thought to drive Alzheimer’s, found among patients getting the highest dose of aducanumab on their PET scans.

However, researchers showed the same result at the end of two years, too – concluding that the drug’s amyloid-removing effects would appear to have plateaued in the last 12 months.

Geoffrey Porges, a biotech analyst at Leerink, said, “It’s great that aducanumab is producing negative amyloid scans after two years, but the drug’s effect on patients’ cognition seems to top out in the same time frame. Once patients on the high dose of the drug hit the two-year mark, their scores on mental exams declined at roughly the same rate seen on other, less effective doses of aducanumab. That makes Biogen’s latest data mixed, but incrementally positive.”

Biogen’s result, however, is not yet conclusive as they are still running their phase three trial, which is due in 2019. The company is currently running two identical trials on about 2,700 patients in total. The results will be placebo-controlled and presented in full. Moreover, if the results are positive, Biogen will be sitting on history’s first disease-modifying Alzheimer’s therapy.

Unfortunately, not all trials show success. Merck’s hypothesis was that if you target an enzyme called BACE, you can halt the production of amyloid before it has the chance to build up in the brain and hamper cognitive function. However, Merck’s data showed that its BACE blocker failed to treat Alzheimer’s in a 2,000-patient trial.

The Merck trial “was probably the last of its kind,” expressed a senior vice president at Eli Lilly, Dr Dan Skovronsky, who is slated to take over the company’s research operation next year. “The more we learn, the more we think you have to start treating earlier and earlier,” he added. MIMS

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