Anti-PD-L1 Immunotherapy Investigated in Early Alzheimer Disease
KEY TAKEAWAYS
- IBC-Ab002, an investigational short-lived anti-PD-L1 antibody, was generally well tolerated in a phase 1b first-in-human trial of early Alzheimer disease.
- No treatment-related serious adverse events or amyloid-related imaging abnormalities were observed.
- Exploratory CSF biomarker findings suggested directional reductions in neurogranin, total tau, and p-tau181 at the highest dose, but results were not statistically significant.
Treatment with the investigational anti–programmed death-ligand 1 (PD-L1) IBC-Ab002 (ImmunoBrain Checkpoint, Palm Beach Gardens, FL), an investigational short-lived anti-PD-L1 antibody, showed an acceptable safety profile and exploratory biomarker signals in people with early Alzheimer disease (AD), according to phase 1b findings published in Nature Medicine and presented at the 2026 Alzheimer’s Association International Conference (AAIC). Although the study was designed to assess safety, exploratory analyses suggested directional reductions in cerebrospinal fluid (CSF) biomarkers of neuronal and synaptic injury at the highest dose.
The randomized, double-blind, placebo-controlled first-in-human trial enrolled 40 participants with biomarker-confirmed mild cognitive impairment due to early AD or mild AD dementia across 11 centers in the United Kingdom, Israel, and the Netherlands. Participants were randomized to receive intravenous IBC-Ab002 (n=30) or placebo (n=10) in 5 ascending-dose cohorts (1 to 30 mg/kg). Four infusions were administered 12 weeks apart over 48 weeks. The primary end point was safety and tolerability; pharmacokinetics, immune activation, biomarkers, and cognition were exploratory outcomes.
Data Highlights
- No treatment-related serious adverse events or amyloid-related imaging abnormalities (ARIA) were observed.
- The most common adverse events among treated participants were fatigue (26.7%), headache (23.3%), and infusion-related reactions (20.0%), which were primarily grade 1 or 2.
- At 48 weeks, the 30-mg/kg cohort showed directional reductions versus placebo in CSF neurogranin (−23.1%), total tau (−12.4%), and phosphorylated tau181 (−11.0%), although none reached statistical significance.
- The study was not powered to evaluate clinical efficacy, and no treatment-related effects on cognition were demonstrated.
The investigators noted that the biomarker analyses were exploratory and based on a small subset of participants who underwent optional end-of-study lumbar puncture.
Source
Croese, T., Mummery, C.J., Bregman, N. et al. Immunotherapy with a short-lived anti-PD-L1 antibody in Alzheimer’s disease: a phase 1b, randomized, double-blind trial. Nat Med (2026). https://doi.org/10.1038/s41591-026-04547-8
Croese T, Mummery C, Bregman N, et al. From bench to bedside: safety and biomarker effects of anti-PD-L1 IBC-Ab002 immunotherapy in early Alzheimer’s patients. Poster presented at the Alzheimer's Association International Conference (AAIC); July 12–15, 2026; London, United Kingdom, and online.