Researchers have demonstrated renewed interest in vaccines that treat Alzheimer’s. The treatments remove toxic proteins from the brain. The author of a recent article in Reuters interviewed ten researchers and company executives for updates.

The current interest follows the initial attempt and failure over 20 years ago when 6% of the trial’s volunteers developed severe brain inflammation.

The research teams then turned to infusing targeted man-made antibodies that avoid the patient’s immune system. The goal was to rid the body of tau and amyloid proteins that were believed to be the cause of Alzheimer’s in people with early-stage disease.

A Return to the Original Theory

After years of failure many experts began to question that theory. However, the FDA’s recent approval of Leqembi, designed to reduce amyloid plaques in the brain, opened the flood gates.

CEO Mei Mei Hu at Vaxxinity, said that Leqembi’s slowing of cognitive decline and the FDA approval thereof, enforces the amyloid hypothesis.

Vaxxinity appears to be furthest along with the completion of a Phase 2 trial (UB-311) in Taiwan with 43 participants. Data reports that the vaccine was both tolerable and safe 78 weeks after initial monitoring. Almost all volunteers produced a response with no brain swelling. Six patients (14%) experienced brain bleeding which is common with infusions.

Vaxxinity is looking for a partner to fund a confirmatory trial. Yet Alzheimer’s vaccines, still in its early stages, will need larger and longer clinical trials to prove their true efficacy.

At least seven completed or actively recruiting Alzheimer’s clinical trials investigating vaccines are currently underway according to ClinicalTrials.gov. If successful, the vaccines will be less costly and much easier to administer to millions of people worldwide.

Testing the New Theory

Scientists at Vaxxinity Inc., AC Immune SA, and Prothena Biosciences believe that they have a better understanding of the problems that occurred with the initial attempt at formulating a vaccine. They are now testing shots that are intended to create an immune response that does not cause excess inflammation.

Reisa Sperling, M.D. an Alzheimer’s researcher at Boston’s Brigham Center agrees that vaccines will have a critical role in the future prevention of Alzheimer’s. Dr. Sperling is considering conducting a study of asymptomatic individuals who are cognitively normal with Alzheimer’s proteins in their blood but not enough to register on brain scans.

About the New Targets

Although the initial Alzheimer’s vaccine appeared to be beneficial, it also set off the immune system’s T-cells that are created to only target infected cells. On the other hand, newer vaccines target immune cells (B cells) that produce antibodies.

Michael Rafii, M.D. of SOCAL, described its Phase 1 trial as not causing any brain swelling yet the number of participants reporting a response was minimal. The team is in the process of reformulating the vaccine.

Andea Pfiefer, AC Immune CEO, offered that the continuous immune response would explain the absence of bleeding or brain swelling that has been occurring in monoclonal antibodies like Leqembi or similar vaccines that peak after infusion.

AC Immune is in collaboration with Johnson & Johnson on a vaccine to target tau, a toxic Alzheimer’s protein also related to the death of brain cells. Prothena Biosciences was spun out about ten years ago from the company that was a co-developer of the original Alzheimer’s vaccine. Next year, the team anticipates a study of a vaccine targeting both tau and amyloid beta developed to prevent Alzheimer’s. Prothena is also actively involved with a Phase 1 trial investigating an anti-amyloid antibody as well as an anti-tau antibody with a license at Myers Squibb.

You can read more about these recently developments regarding Alzheimer’s vaccines over at Reuters.