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

United Neuroscience’s vaccine candidate UB-311 was safe and well-tolerated in patients with mild Alzheimer’s disease, according to results from a Phase 2a clinical trial.

Patients who participated in this trial are now eligible to enroll in a long-term follow-up study that will continue to assess the vaccine’s safety for 108 weeks.

Trial results, “Active Immunotherapy with UB-311 vaccine: Results from a Phase IIa, randomized, double-blind, placebo-controlled, 3-arm parallel-group, multicenter study” were recently presented during the 14^th International Conference on Alzheimer’s and Parkinson’s Diseases and related neurological disorders in Lisbon, Portugal.

UB-311, developed by United Neuroscience, a spin-off of United Biomedical, is a synthetic peptide vaccine that triggers 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.

Results from a Phase 1 trial (NCT00965588) showed that UB-311 was safe and well-tolerated, and able to trigger high levels of anti-beta-amyloid antibodies in patients with mild to moderate Alzheimer’s disease. 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, with mild Alzheimer’s dementia. Most participants (81.4%) were APOE-E4 carriers, a genetic factor associated with a higher risk of developing early Alzheimer’s disease.

Patients were randomized to receive intramuscular injections of UB-311 at different doses or a placebo (control). Among those who received the vaccine, one group received a total of seven doses of UB-311 (three priming doses followed by four boosters) and the other group a total of five doses of UB-311 (three priming doses followed by two boosters) and two doses of placebo.

An effective vaccine usually requires more than one administration in the form of a prime-boost. After an initial immunization, a booster injection re-exposes the body to the same antigen, against which the body will create an immune response.

The study’s primary objectives were the safety/tolerability of the vaccine and its ability to trigger an immune response compared with the placebo after 78 weeks. Secondary goals included assessing the vaccine’s effect on patients’ cognitive, neuropsychiatric, and other functioning, including learning and memory assessed by positron-emission tomography (PET) imaging.

Magnetic resonance imaging (MRI) scans were obtained at the beginning of the study, and every three months following vaccination to assess amyloid-related imaging abnormalities (ARIA), meningoencephalitis (inflammation of the meninges and brain), and to track brain volume.

In agreement with recent top-line results, among the 41 patients who completed the 78 weeks, there were no cases of meningoencephalitis or ARIA-edema. The most common adverse events were injection site-related reactions and asymptomatic ARIA-hemosiderin (ARIA-H), which is characterized by small deposits of iron that manifest as dark spots on MRI images.

“To date, UB-311 has been well-tolerated, as continuously assessed by clinical exam and MRI, with over 300 vaccine doses administered from both Phase I and Phase IIa studies,” the researchers wrote.

Patients from this Phase 2 study are eligible to join the Phase 2 extension study (NCT03531710) that will evaluate the long-term safety, tolerability, and potential efficacy of UB-311. Patients will receive three or five doses of UB-311 for 96 weeks, followed by a 12-week follow-up period.