AbstractBackgroundImmune checkpoint inhibitors (ICI) have been suggested as a unique therapy for treating neurodegenerative diseases. IBC‐Ab002 is a novel fully human anti‐PD‐L1 monoclonal antibody developed by ImmunoBrain Checkpoint (IBC) for the treatment of Alzheimer’s disease (AD).In cancer patients, ICI treatments are often associated with immune‐related adverse events (irAEs), which are side effects that manifest as either temporary or permanent autoimmune conditions caused by drug administration. One example of such an event is T cell‐mediated pancreatic tissue damage leading to autoimmune diabetes. The management of irAE often involves treatment discontinuation until symptoms relief, which has unwanted impact on the effectiveness of therapies that depend on continuous drug exposure.Unlike common ICI used in oncology, PD‐L1 blockade mechanism of action in mouse models of neurodegenerative diseases was shown to be dependent on transient immune system stimulation. Accordingly, IBC‐Ab002 antibody was designed with modifications on its Fc backbone that shorten its circulation half‐life, to meet the pharmacokinetic and pharmacodynamic characteristics needed for treating AD.MethodSurrogate antibodies that block mouse PD‐L1 and share the same hIgG1 Fc‐modifications as IBC‐Ab002 were generated and tested for their propensity to accelerate the onset of autoimmune diabetes in NOD transgenic mice, which spontaneously develop type 1 diabetes. Mice were monitored for their blood‐glucose levels, weight, and survival – for both the acute and long‐term duration following antibody administration.ResultWe found that administration of a therapeutically effective dose of IBC‐Ab002’s surrogate antibody led to fewer cases of premature diabetes onset in NOD mice, when compared with an antibody variant that contains no Fc‐modifications. Furthermore, no excessive weight loss, change in the time‐course of spontaneous diabetes onset or early mortality, were found following IBC‐Ab002’s surrogate treatment, compared with isotype‐control treated mice, in a 200‐days follow‐up assessment.ConclusionWe demonstrate that the clearance rate of the antibody inversely‐relates to the probability of developing an adverse immune response, and that no delayed long‐term irAEs are expected once full clearance of the antibody was achieved. Overall, these findings suggest that shortening the half‐life of anti‐PD‐L1 antibodies in treatments that do not necessitate continuous exposure can considerably increase the safety profile.