UB-311 Vaccine Safe, Effective in Mild Alzheimer’s Patients, Phase 2a Trial Suggests

United Neuroscience’s Alzheimer’s vaccine candidate UB-311 was found safe and well-tolerated, triggering an antibody response against beta-amyloid in most of the patients, according to Phase 2a trial results.

“These early results suggest a clinical response and support the continued and rapid development of UB-311. The intent of this Phase 2a study was to acquire directional information on the safety, tolerability and therapeutic potential of UB-311 in patients with Alzheimer’s disease,” Mei Mei Hu, CEO of United Neuroscience, said in a press release.

UB-311, developed by United Neuroscience, a spin-off of United Biomedical, is a synthetic peptide vaccine designed to trigger an antibody response against beta-amyloid — whose accumulation in the brain is a hallmark of Alzheimer’s disease — clearing it away without causing potentially harmful inflammation.

A previous Phase 1 clinical trial (NCT00965588), which tested UB-311 in 19 patients with mild to moderate Alzheimer’s disease, revealed the vaccine was safe and well-tolerated, and able to trigger high levels of anti-beta-amyloid antibodies in all patients. Moreover, the data suggested that the treatment led to a stabilization of patients’ cognitive abilities.

The Phase 2a trial (NCT02551809), conducted at multiple sites in Taiwan, enrolled 43 patients, ages 60 to 90 years old, with mild Alzheimer’s disease. Patients were randomized to receive intramuscular injections of either:

• three priming doses followed by four boosters — a total of seven doses of UB-311
• three priming doses followed by two boosters — a total of five doses of UB-311 and two doses of placebo
• seven doses of placebo

An effective vaccine usually requires more than one immunization in the form of a prime-boost. This strategy is administered in several stages that present the same antigen (what the body will create an immune response against) through different vectors.

The study’s primary objectives were the safety/tolerability of the vaccine and its ability to trigger an immune response (in the form of antibodies against beta-amyloid) after 78 weeks. Secondary goals included assessing the vaccine’s effect on patients’ cognitive, neuropsychiatric, and other functioning, including learning and memory, as well as the burden of beta-amyloid, assessed by positron-emission tomography (PET) imaging in selected brain areas.

The top-line results showed a 96% response rate in all primary objectives. All secondary goals, including beta-amyloid PET burden, cognition, and behavioral parameters, showed a tendency toward improvement with UB-311. Due to the limited number of participants, these benefits, however, showed no statistical significance.

Patients who completed the Phase 2a trial will roll over into a long-term extension study where they will continue to receive UB-311.

“The intent of this Phase 2a study was to acquire directional information on the safety, tolerability and therapeutic potential of UB-311 in patients with Alzheimer’s disease,” Hu said. “These early results suggest a clinical response and support the continued and rapid development of UB-311.”

“The positive results show that we can safely raise and maintain anti-Aβ antibody titers in a predictable and sustained manner,” said Peter Powchik, executive vice president of research and development at United Neuroscience.

“High response rates, reproducibility of response and generation of antibodies directed to relevant toxic protein species are key elements of an effective therapeutic vaccine for neurodegenerative conditions. The [United Neuroscience] platform is proving that it can deliver on these requirements,” Powchik added.

These results and those that will be further analyzed will be presented at upcoming medical meetings, including the 14th International Conference on Alzheimer’s and Parkinson’s Diseases.