Lausanne, 19 October 2020 Invitation to the Extraordinary Shareholders' Meeting Date: Friday, 20 November 2020 | 2:00 PM Central European Time Place: EPFL Innovation Park, Building B | 1015 Lausanne | Switzerland I. Fore

Lausanne, 19 October 2020

the Extraordinary Shareholders' Meeting

Contact information: AC Immune SA, Investor Relations, EPFL Innovation Park, Building B, 1015 Lausanne, Switzerland,

Tel: +41 21 345 91 22 | Email: egm@acimmune.com | Visit our Webpage: https://ir.acimmune.com/events/egm

The Board of Directors has decided to call

an extraordinary shareholders' meeting and to ask you to approve the election of Prof. Carl June as member of the Board of Directors

for a term until the end of the next Annual General Meeting.

Election of Carl June as member of the

The Board of Directors has the great pleasure

to propose the election of Carl June as member of the Board of Directors for a term until the end of the next Annual General Meeting.

Prof. June is Richard W. Vague Professor in Immunotherapy, Director of the Center for Cellular Immunotherapies and Director of

the Parker Institute for Cancer Immunotherapy University of Pennsylvania, Perelman School of Medicine, USA.

Prof. June is a graduate of the Naval Academy

in Annapolis, USA, and Baylor College of Medicine in Houston, USA, where he received his medical degree. Prof. June also completed

graduate training in immunology and malaria with Dr. Paul-Henri Lambert at the World Health Organization, Geneva, Switzerland and

post-doctoral training in transplantation biology with E. Donnell Thomas and John Hansen at the Fred Hutchinson Cancer Research

Center in Seattle USA.

Due to his lifelong work on lymphocyte activation,

Prof. June is considered a world authority on mechanisms related to immune tolerance and adoptive immunotherapy in the fields of

cancer and chronic inflammation. He and his team pioneered the groundbreaking work in immunotherapy in which patients with refractory

and relapsed chronic lymphocytic leukemia are treated with genetically engineered versions of their own T cells. This CAR-T

therapy approach, which trains the immune system to attack and destroy cancer cells, has helped patients achieve remissions that

last for years. The treatment was approved by the USA FDA in 2017 as a treatment for leukemia and lymphoma, opening a new era of

innovative treatments and personalized medicine for cancer patients.

At the University of Pennsylvania, the June

lab continues to develop new CAR cell therapies for other indications, including immunotherapy for the treatment of uncurable brain

tumors. Prof. June has published more than 500 manuscripts and is the recipient of numerous prizes and honors. He was recently

named the most influential academic scientist in the biopharmaceutical industry by FierceBiotech and has received many honors including

election to the Institute of Medicine, the National Academy of Sciences, the American Philosophical Society and the American Academy

of Arts and Sciences. He has received numerous awards, including the William B Coley award, the Richard V Smalley Memorial Award

from the Society for Immunotherapy of Cancer, the AACR-CRI Lloyd J. Old Award in Cancer Immunology, the Philadelphia Award in 2012,

the Taubman Prize for Excellence in Translational Medical Science in 2014 (shared w S. Grupp, B. Levine, D. Porter), the Paul Ehrlich

and Ludwig Darmstaedter Prize (shared w J. Allison), the Novartis Prize in Immunology (shared w Z. Eshaar and S. Rosenberg), the

Karl Landsteiner Memorial award, the Debrecen

Award, the Karnofsky Award from the American Society of Clinical Oncology, and a lifetime achievement award from the Leukemia and

Contact information: AC Immune SA, Investor Relations, EPFL Innovation Park, Building B, 1015 Lausanne, Switzerland,

Tel: +41 21 345 91 22 | Email: egm@acimmune.com | Visit our Webpage: https://ir.acimmune.com/events/egm

Your vote is important to AC Immune SA:

please read carefully the Organizational Notes in Chapter III of this Invitation to ensure that your vote will be properly cast.

Contact information: AC Immune SA, Investor Relations, EPFL Innovation Park, Building B, 1015 Lausanne, Switzerland,

Tel: +41 21 345 91 22 | Email: egm@acimmune.com | Visit our Webpage: https://ir.acimmune.com/events/egm

Kindly find hereafter the agenda item and proposal of the Board

of Directors in connection with the extraordinary general meeting of AC Immune SA:

The Board of Directors proposes

for a term until the end of the next Annual General Meeting the election of Carl June as member of the Board of Directors.

1. Coronavirus Restrictions

No "in-person" Meeting for Shareholders

The persisting situation

surrounding the coronavirus (Covid-19) and the updated measures prescribed by the Swiss Federal Council to combat this infectious

disease have prompted us to take the same legal steps for the Extraordinary General Meeting as we took for the Annual General Meeting

2020. Our primary goal is to protect the health of our shareholders and employees as far as possible.

Because of this special

situation, we have decided to reduce the Extraordinary General Meeting to the mandatory part as stipulated by Swiss law and by

the Company's Articles of Association. We will hold a meeting with a minimal attendance to which shareholders will not be

invited to attend in person, and only hold the necessary election and vote. In particular, the members of the Board of Directors

and of the Executive Committee will not be available for discussion.

Voting via the Independent Proxy

Based on article 27 of the

Swiss Federal Council's "Ordinance 3 on Measures to Combat the Coronavirus (COVID-19)" of 19 June 2020, as subsequently

amended, the Board of Directors resolved that the shareholders can exercise their rights exclusively through the independent proxy

Reymond & Associ s, represented by Mr. Denis Cherpillod, Attorney at Law, Avenue de la Gare 1, case postale 7255, 1002

Lausanne, Switzerland. You can do so following the instructions in Section 4.2 below.

2. Eligibility to Vote

registered in the share register maintained by our transfer agent, Computershare

Trust Company N.A. ("Computershare"),

up to and including 19 October 2020 at close of NASDAQ ("Record Date") will be eligible to vote at the Extraordinary

General Meeting. Shareholders selling their shares prior to the Extraordinary General Meeting

are excluded from voting.

New shares acquired between

20 October 2020 and 23 November 2020 (at the opening of NASDAQ) will not give any corresponding voting rights for this Extraordinary

These restrictions on voting

do not impact trading of AC Immune SA shares held by registered shareholders before, during or after the Extraordinary General

3. Invitation and Ancillary Material

Shareholders who are registered

with Computershare receive their Invitation to the Extraordinary General Meeting directly from Computershare. With their Invitation,

these shareholders are receiving the means to vote electronically with the individual shareholder number ("QR Code")

and a personalized Proxy Card enabling them to give their voting instructions to the independent proxy. Section 4 below describes

Shareholders who are "Beneficial

Owners", holding their AC Immune SA shares on 19 October 2020 through their broker or bank, are unknown to AC Immune SA

or to Computershare. Their Invitation and material are issued by Computershare and channeled through their broker or bank. These

shareholders should be able to vote on the portal of their bank or broker. If the receipt of the Invitation is delayed or impossible

due to deficiencies in the postal delivery services, these shareholders may nevertheless access the Invitation and ancillary material

for the Extraordinary General Meeting and download a generic proxy card on AC Immune SA's 's website at https://ir.acimmune.com/events/egm.

4. Voting (Instructions to Independent

Shareholders can vote exclusively

through the independent proxy prior to the Extraordinary General Meeting (see Section 1.2 of Chapter III above).

The independent proxy will

be physically present at the Extraordinary General Meeting to vote on behalf of the shareholders who issued instructions to him.

Contact information: AC Immune SA, Investor Relations, EPFL Innovation Park, Building B, 1015 Lausanne, Switzerland,

Tel: +41 21 345 91 22 | Email: egm@acimmune.com | Visit our Webpage: https://ir.acimmune.com/events/egm

AC Immune SA recommends

that shareholders do vote electronically through the Computershare portal with the individual shareholder number ("QR Code")

or, for "Beneficial Owners", using the portal of their bank or broker. The independent proxy will receive the consolidated

electronic instructions from shareholders, banks and brokers via Computershare.

Electronic voting instructions

must be given no later than 18 November 2020 at 11:59 PM, US Eastern Standard Time.

who do not wish to vote electronically may give their written instructions to the independent