Peer-reviewed results from Phase 1b/2a Trial of Anti-pTau Active Immunotherapy from AC Immune Published in eBioMedicine

Peer-reviewed results from Phase 1b/2a Trial of Anti-pTau Active Immunotherapy from AC Immune Published in eBioMedicine

Detailed results from completed Phase 1b/2a trial of ACI-35.030 and JACI-35.054 demonstrated that two different active immunotherapy formulations against the same target can induce a differential antibody response in individuals with early Alzheimer’s disease

ACI-35.030, developed using AC Immune’s SupraAntigen® technology, generated rapid, potent polyclonal response against pathological forms of Tau after first dose

No clinically relevant safety and tolerability observations were reported

ACI-35.030 (JNJ-64042056) selected to advance and now in ongoing potentially registration-enabling Phase 2b ReTain clinical trial in preclinical Alzheimer’s disease

Lausanne, Switzerland, 25, 2025 -- AC Immune SA (NASDAQ: ACIU), a clinical-stage biopharmaceutical company pioneering precision therapeutics for neurodegenerative diseases, today announced the peer-reviewed publication in eBioMedicine of results from the completed Phase 1b/2a trial of active immunotherapy ACI-35.030’s (JNJ-2056) partnered with Janssen Pharmaceuticals, Inc., a Johnson & Johnson company. ACI-35.030 generated a rapid, robust and durable polyclonal response against pathological forms of Tau including phosphorylated Tau (pTau) and brain-derived Tau (enriched paired helical filament, ePHF). There were no clinically relevant safety or tolerability observations for either ACI-35.030 or JACI-35.054.

Dr. Andrea Pfeifer, CEO of AC Immune SA, commented: “These data show that ACI-35.030 (JNJ-2056) was well tolerated at all tested doses and induced a rapid and sustained response against pathological Tau, while requiring less frequent dosing to maintain titers as compared to monoclonal antibodies. Safety and rapid, durable responses are key advantages of active immunotherapies, which make them particularly well suited to the long-term treatment needed to achieve precision prevention. ACI-35.030 is continuing to progress according to plan in the Phase 2b ReTain trial, being conducted by our development partner Johnson & Johnson.”

Dr. Pfeifer added: “This study also demonstrated the ability of AC Immune’s SupraAntigen® platform to generate active immunotherapies that are highly differentiated from other approaches even when the immunogen is identical. We are encouraged by the excellent performance of the SupraAntigen® technology as this also powers our ACI-24.060 anti-Abeta active immunotherapy program in Phase 2 development where further results are expected in H1 next year.”

The publication is entitled "Safety and immunogenicity of two Tau-targeting active immunotherapies, ACI-35.030 and JACI-35.054, in participants with early Alzheimer’s disease: a Phase 1b/2a, multicentre, double-blind, randomised, placebo-controlled study" and reports the following key findings from the completed trial ( NCT04445831 ):

ACI-35.030 is based on AC Immune’s proprietary SupraAntigen® technology which anchors the pTau peptide in a liposome and also incorporates non-Tau T-cell epitopes and adjuvants. JACI-35.054 covalently linked the immunogen to the carrier protein CRM197 and was mixed with adjuvants. Both active immunotherapies used the same target pTau peptide sequence.

ACI-35.030 required only one injection to induce anti-pTau Immunoglobulin G (IgG) antibody titers in all participants and consistently boosted levels with subsequent immunizations. JACI-35.054 raised a more heterogenous anti-pTau IgG antibody response and required multiple administrations to reach consistent titers.

All participants across all dose-levels were considered anti-pTau IgG responders at 2 weeks post treatment with ACI-35.030. In the two high-dose cohorts, response rates remained between 94% and 100% until week 74. Most participants generated an anti-ePHF antibody response after the first administration and antibody levels further increased with additional immunizations.

Antibody titers against unphosphorylated (normal) Tau declined and were not boosted with subsequent administrations of ACI-35.030, demonstrating specific targeting of the pathological Tau species. In contrast, JACI-35.054 induced antibody titers against normal Tau after the second treatment and these increased with subsequent administrations.

An exploratory post-hoc analysis showed that at multiple time points for the two highest doses ACI-35.030, treatment resulted in a significant (p$4.5 billion in potential milestone payments plus royalties.

SupraAntigen® is a registered trademark of AC Immune SA in the following territories: AU, EU, CH, GB, JP, RU, SG and USA. Morphomer® is a registered trademark of AC Immune SA in CN, CH, EU, GB, JP, KR, NO, RU and SG.

The information on our website and any other websites referenced herein is expressly not incorporated by reference into, and does not constitute a part of, this press release.

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Forward looking statements

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