Coming off a series of setbacks in amyloidosis and a recent round of layoffs, Prothena is hoping that early data for its Alzheimer's disease (AD) candidate — as well as the potential of a preclinical asset — will attract a partner. The drugmaker shared results on Thursday from the Phase I ASCENT clinical programme, which is evaluating varying dose levels of a once-monthly, subcutaneous anti–beta-amyloid monoclonal antibody (mAb), PRX012, in patients with early symptomatic AD.While Prothena said the candidate was similarly capable of clearing amyloid plaques compared with the two marketed mAbs, Eli Lilly's Kisunla (donanemab-azbt) and Eisai and Biogen's Leqembi (lecanemab), it was linked to higher overall rates of amyloid-related imaging abnormalities with oedema or effusion (ARIA-E).As a result, the company described PRX012 as having a "non-competitive ARIA-E profile" in patients with early symptomatic AD. Still, Chief Development Officer Chad Swanson reiterated Prothena's goal to secure a partnership to advance development of PRX012, as well as its preclinical beta-amyloid transferrin receptor (TfR) antibody PRX012-TfR.The biotech said that observations from ASCENT, as well as feasibility studies of PRX012-TfR, suggest the antibody "may represent an opportunity to significantly lower the risk of ARIA and quickly reduce amyloid plaque with a once-monthly subcutaneous administration," with findings in mice models demonstrating "increased brain exposure and…rapid targeting of beta-amyloid plaques."Plaque attackThursday's readout included data from 228 participants in the ASCENT-2 portion of the programme with early symptomatic AD who were either heterozygous for APOE4, or non-carriers. Individuals who are homozygous for the gene are at higher risk to experience ARIA when receiving an anti–beta-amyloid mAb.Participants were randomised to receive either a 45-mg, 70-mg, 200-mg or 400-mg dose of PRX012, or placebo. In the 400-mg dose cohort, PRX012 reduced amyloid PET levels to a mean of 27.47 centiloids (CL) at month 12; Kisunla has a defined amyloid negativity threshold of ≤24.1 CL, and Leqembi's is ≤30 CL. However, 41.7% of patients in the high-dose group experienced ARIA-E. Lilly recently presented data from a modified titration schedule of Kisunla showing a 14% incidence rate for the complication (see – Physician Views Results: Kisunla widens its lead over Leqembi with new, safer dosing).Prothena said it does not plan on sharing additional data from ASCENT while it hunts for a partner on its AD assets.