Anti-MTBR tau antibody treatment for Alzheimer’s safe, well-tolerated, in phase 1 study

Prothena Corp. reported positive topline results from its phase 1 single ascending dose study of PRX005, an investigational tri-epitopic antibody for treatment of Alzheimer’s disease.

According to a company press release, PRX005 binds with high affinity to the R1, R2 and R3 repeats within the microtubule binding region (MTBR) of tau and targets 3R and 4R isoforms.

Prothena conducted a randomized, placebo-controlled study of 19 healthy volunteers who were enrolled in three PRX005 dose-level cohorts: low, medium or high dose. Participants received a single IV dose of the investigational treatment or placebo and were monitored for 2 months.

Results showed all three dose levels were generally safe and well-tolerated, with plasma drug concentrations of PRX005 increasing in a dose-proportional manner, the release stated. No serious treatment-emergent adverse events were reported.

“We developed PRX005 to uniquely target a key region within the MTBR of tau to reduce pathogenic tau uptake into neurons, an attribute that has not been similarly achievable with antibodies targeting other regions of tau,” Gene Kinney, PhD, president and CEO of Prothena, said in the release. “These topline phase 1 data, together with the mounting scientific evidence suggesting that tau propagation could be mediated by MTBR-tau seeds, underscores the potential of PRX005 in treating Alzheimer’s disease.”

The company is working with Bristol Myers Squibb to advance the development of PRX005 and plans to announce results from the ongoing, phase 1 multiple ascending dose trial in patients with AD in late 2023, the release stated.