AC Immune Progress Update on Phase 2 Active Immunotherapy Clinical Pipeline for Alzheimer's and Parkinson's diseases ABATE Phase 1b/2 AD trial of ACI-24.060 completed enrollment of cohorts 1 and 2 and is ex

AC Immune Progress Update on Phase 2 Active Immunotherapy

Clinical Pipeline for Alzheimer's and Parkinson's diseases

Switzerland, January 3, 2024 - AC Immune SA (NASDAQ: ACIU), a clinical-stage biopharmaceutical company pioneering precision

medicine for neurodegenerative diseases, today provided an update on positive progress in its active immunotherapy programs, with three

Phase 2 trials progressing to key clinical milestones in 2024.

Andrea Pfeifer, CEO of AC Immune SA, commented: "AC Immune has continued steady clinical development progress throughout

2023, and we end the year in a very strong position. We now have three active immunotherapies from our precision medicine pipeline in

Phase 2 clinical testing, with key milestones for ACI-24.060 in 2024. We are moving ever closer to delivering therapeutics that use the

immune system to slow the onset and ultimately prevent neurodegenerative diseases, much like vaccines for infectious disease. To succeed,

we must pursue earlier diagnoses and begin using active immunotherapies before permanent damage occurs to neurons."

"Our financial position was

reinforced in December by our successful USD50 million equity offering, which was supported by some of the world's preeminent specialist

investors, as well as a CHF15 million milestone payment. This was the first of two payments from our partner relating to the Phase 2b

ReTain trial of ACI-35.030 in preclinical AD patients. With the second milestone payment expected in 2025, we have sufficient financing

to support operations into 2026."

ACI-24.060: AC Immune's

wholly-owned anti-amyloid beta (Abeta) active immunotherapy (vaccine)-candidate. The ABATE randomized, double-blind, placebo-controlled

Phase 1b/2 trial of ACI-24.060 for treatment of Alzheimer's disease (AD) continues fully blinded, with cohorts 1 and 2 enrolled

and cohort 3 enrollment to be completed in January. Following data safety monitoring board (DSMB) review, no safety concerns have been

raised to date, consistent with previous results. Immunogenicity of the vaccine is very encouraging with clear evidence of anti-Abeta

antibody responses against toxic Abeta species observed in the blinded data. The six-month Abeta positron emission tomography (PET) imaging

results are expected in H1 2024, and the 12-month Abeta PET data are expected in H2 2024.

ACI-7104.056: AC Immune's

wholly-owned anti-alpha-synuclein (a-syn) active immunotherapy, to treat Parkinson's disease (PD). Enrollment of cohort 1 in the

Phase 2 VacSYn clinical trial evaluating ACI-7104.056, is completed, with 16 patients randomized, and cohort 2 enrollment and randomization

has begun. No safety concerns have been reported to date with no reports of moderate or severe adverse events. Safety and immunogenicity

updates from the trial will be reported in H2 2024.

ACI-35.030: AC Immune's

partnered investigational targeted active immunotherapy, selective for pathological phosphorylated Tau (pTau). As recently announced,

AC Immune's development partner launched ReTain, a Phase 2b clinical study to evaluate ACI-35.030 (JNJ-64042056) in patients with

preclinical AD. The trial will randomize approximately 500 pre-symptomatic participants with confirmed early-stage Tau pathology and treat

them for a four-year period, with interim analyses potentially allowing for acceleration towards a regulatory filing. Under the terms

of the licensing agreement, AC Immune has received a milestone payment of CHF15 million and expects to receive another milestone payment

of CHF 25 million related to achieving an undisclosed enrollment target in 2025.

AC Immune SA is a clinical-stage biopharmaceutical

company that aims to become a global leader in precision medicine for neurodegenerative diseases, including Alzheimer's disease,

Parkinson's disease, and NeuroOrphan indications driven by misfolded proteins. The Company's two clinically validated technology

platforms, SupraAntigen and Morphomer , fuel its broad

and diversified pipeline of first- and best-in-class assets, which currently features sixteen therapeutic and diagnostic programs, five

of which are currently in Phase 2 clinical trials and one of which is in Phase 3. AC Immune has a strong track record of securing strategic

partnerships with leading global pharmaceutical companies, resulting in substantial non-dilutive funding to advance its proprietary programs

and >$3 billion in potential milestone payments.

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, GB, JP, KR, NO and RU.

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.

For further information, please contact:

Forward looking statements

This press release contains statements

that constitute "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933 and Section 21E

of the Securities Exchange Act of 1934. Forward-looking statements are statements other than historical fact and may include statements

that address future operating, financial or business performance or AC Immune's strategies or expectations. In some cases, you can

identify these statements by forward-looking words such as "may," "might," "will," "should,"

"expects," "plans," "anticipates," "believes," "estimates," "predicts,"

"projects," "potential," "outlook" or "continue," and other comparable terminology. Forward-looking

statements are based on management's current expectations and beliefs and involve significant risks and uncertainties that could

cause actual results, developments and business decisions to differ materially from those contemplated by these statements. These risks

and uncertainties include those described under the captions "Item 3. Key Information - Risk Factors" and "Item

5. Operating and Financial Review and Prospects" in AC Immune's Annual Report on Form 20-F and other filings with the Securities

and Exchange Commission. Forward- looking statements speak only as of the date they are made, and AC Immune does not undertake any obligation

to update them in light of new information, future developments or otherwise, except as may be required under applicable law. All forward-looking

statements are qualified in their entirety by this cautionary statement.