Vaccinex (NASDAQ: VCNX) is a clinical-stage biotechnology company developing pepinemab, a humanized IgG4 monoclonal antibody that blocks Semaphorin 4D (SEMA4D) signaling through astrocyte plexin-B1 receptors, reducing reactive astrocyte activation and downstream neuroinflammation. The mechanism represents a disease-modifying approach in Alzheimer's disease mechanistically distinct from amyloid-directed antibodies (lecanemab, donanemab) and tau-directed programs (Biogen's diranersen ASO, Voyager's VY1706 AAV gene therapy).
Vaccinex presented Phase 1b/2 SIGNAL-AD data at AAIC 2026 on Monday July 13 in the Featured Research Session titled 'Alzheimer's therapy: mechanisms beyond amyloid,' chaired by Chief Operating Officer Elizabeth Evans, PhD. The presentation 'Glial Biomarkers Associated With Disease Progression Are Regulated By SEMA4D Blocking Antibody Pepinemab in Patients With Early-Stage AD' documented that SEMA4D blockade modulates glial biomarkers linked to cognitive decline, synaptic loss, and neuroinflammation. Vaccinex outlined plans for an expanded randomized Phase 2b SIGNAL-AD2 study to test the intervention at scale.
Stories here cover Vaccinex trial readouts, the pepinemab regulatory and clinical path, and the neuroinflammation-directed side of the Alzheimer's pipeline. See [[pepinemab]], [[sema4d]], [[aaic-2026]], and [[alzheimers-disease]] for adjacent threads.
Vaccinex (NASDAQ: VCNX) presented new biomarker data from the Phase 1b/2 SIGNAL-AD trial of pepinemab, a humanized IgG4 monoclonal antibody targeting Semaphorin 4D (SEMA4D), at AAIC 2026 in London on Monday July 13, 2026 from 9:00-10:30 AM London time at ExCeL London. Elizabeth Evans, PhD, Chief Operating Officer and Senior VP of Discovery and Translational Medicine, chaired the Featured Research Session 'Alzheimer's therapy: mechanisms beyond amyloid' and presented results titled 'Glial Biomarkers Associated With Disease Progression Are Regulated By SEMA4D Blocking Antibody Pepinemab in Patients With Early-Stage AD.' The presentation showed that SEMA4D blockade regulates glial biomarkers associated with disease progression in early Alzheimer's disease, supporting the mechanistically distinct approach of targeting neuroinflammation and reactive astrocytes rather than amyloid or tau directly. Vaccinex outlined plans for an enlarged Phase 2b SIGNAL-AD2 study to test the intervention at scale.
The Alzheimer's Association International Conference (AAIC 2026) opens Sunday July 12 and runs through Wednesday July 15 at the ExCeL London, drawing approximately 12,000 researchers and health-care professionals from around the globe. The peptide-adjacent centerpiece already flagged in Wednesday's Vaccinex announcement is the Featured Research Session on Monday July 13 for pepinemab (humanized IgG4 anti-Semaphorin 4D monoclonal antibody), chaired by Elizabeth Evans, PhD, presenting new glial biomarker data from the Phase 1b/2 SIGNAL-AD study alongside plans for the expanded Phase 2b SIGNAL-AD2 trial. AC Immune (NASDAQ: ACIU) will present three programs from its Morphomer platform: a first-in-class TDP-43 PET tracer with encouraging early human imaging data in frontotemporal dementia and ALS, a novel brain-penetrant NLRP3 inhibitor in Phase 1 that supports an orally delivered CNS therapy profile, and an alpha-synuclein Morphomer showing potent, brain-penetrant inhibition of pathology with neuroprotective effects. Eisai will present 50-plus abstracts spanning the lecanemab (LEQEMBI) Alzheimer's disease portfolio, including biomarker, long-term safety, and clinical-utility readouts.
Vaccinex (NASDAQ: VCNX) announced Wednesday July 8, 2026 that it will present new glial biomarker data from the Phase 1/2 SIGNAL-AD study of pepinemab and plans for the expanded Phase 2B SIGNAL-AD2 trial at the Alzheimer's Association International Conference (AAIC) 2026 in London on July 13. Elizabeth Evans, PhD, Chief Operating Officer and Senior VP of Discovery and Translational Medicine, will chair the Featured Research Session. Pepinemab is a humanized IgG4 monoclonal antibody targeting Semaphorin 4D (SEMA4D). The mechanism blocks SEMA4D signaling through astrocyte plexin-B1 receptors, reducing reactive astrocyte activation and downstream neuroinflammation — a disease-modifying approach mechanistically distinct from amyloid- or tau-targeting strategies. Pepinemab is a monoclonal antibody rather than a peptide, but the SEMA4D program sits in the peptide-and-biologic neurodegeneration territory this site tracks alongside the Vera Therapeutics Trutakna (atacicept fusion protein) approval covered yesterday. AAIC readouts to watch: cerebrospinal-fluid glial fibrillary acidic protein (GFAP) and neurofilament light chain (NfL) biomarker shifts on pepinemab treatment.