Lausanne, 22 March 2018 Invitation to the Extraordinary Shareholders' Meeting Date: 27 April 2018, at 15.00 pm Swiss time Place: EPFL Innovation Park Building D, ground floor, Uranus Meeting room, 1015 Lausanne Dear Shar

Lausanne, 22 March 2018

to the Extraordinary Shareholders' Meeting

have the pleasure of informing you that the following industry expert has recently confirmed his interest in joining our team

as member of the Board of Directors of AC Immune SA:

propose to elect Dr. Williams as new member of our Board of Directors and as new member of our Compensation, Nomination &

Corporate Governance Committee.

Furthermore, we propose to increase the

Company's share capital, thereby providing AC Immune SA with additional funds to support its continued efforts in becoming

a global leader in personalized treatment of neurodegenerative diseases.

Agenda Items and Proposals of the Board

Board of Directors proposes the election of Douglas Williams as new member of the Board of Directors, until the end of the next

ordinary General Meeting.

Board of Directors proposes the election of Douglas Williams as new member of the Compensation, Nomination & Corporate Governance

Committee, until the end of the next ordinary General Meeting.

Board of Directors proposes to hold the following separate votes on the compensation of the new member of the Board of Directors:

Board of Directors proposes that shareholders approve an additional maximum amount of non-performance-related compensation for

the new proposed member of the Board of Directors covering the period from 27 April 2018 to 30 June 2018, i.e.,

CHF 11'800 (cash base compensation plus social security costs).

Board of Directors proposes that shareholders approve an additional maximum grant of equity or equity linked instruments for the

new proposed member of the Board of Directors from 27 April 2018 to 30 June 2018 with maximum value of CHF 76'000 (equity

or equity linked instruments value plus social security costs).

The Board of Directors intends to increase

the share capital of the Company as the previous timeline for the increase of authorized capital expired on date 20 October 2017.

This increase enables the Company to secure the necessary future funds to execute its three-pillar strategy targeting Alzheimer's

disease, non-Alzheimer's disease and other neuro-orphan diseases and diagnostics. The Company anticipates to conduct this

financing in two tranches: The first offering (agenda item 4.a) will allow the Company to broaden its existing shareholder base

and issue new shares to institutional investors in a rapid way thus limiting market exposure. The second offering (agenda item

4.b) allows existing investors to subscribe shares at identical terms and conditions as the first offering. Both institutional

investors and existing shareholders will each be served from their own respective offering with identical terms.

The Board proposes accordingly

an ordinary share capital increase for institutional investors as follows:

As for logistical reasons current

shareholders may not be able to participate in the ordinary share capital increase for institutional investors, the Board proposes

an ordinary share capital increase for current shareholders at identical terms as offered in the preceding ordinary share capital

increase as follows:

Please participate electronically or mail

as per the Organizational Matters section at the end of this invitation to vote in this Shareholders' Meeting.

Organizational Matters

1 Invitation and Attendance

Shareholders registered in the share register

maintained by our transfer agent, Computershare Trust Company N.A. at 5:00 pm Eastern Standard Time ("EST") / 11:00 pm

Swiss time on 13 March 2018 are entitled to participate in and vote at the Extraordinary General Meeting. On 21 March 2018, the

invitation and proxy form will be mailed to all holders of record as at 13 March 2018 at 5:00 pm EST / 11:00 pm Swiss time. The

invitation is available for download in the "Investors" section of our website (www.acimmune.com).

If you wish to attend the Extraordinary

General Meeting in person, you will be required to present the enclosed proxy form and a valid government issued proof of identification.

Shareholders of record, who do not attend

the Extraordinary General Meeting in person, may:

(a) grant a proxy to the independent proxy,

Bugnion Ballansat Ehrler, represented by G rald Virieux, avocat, rue de Rive 6, case postale 3143, CH-1211 Geneva 3 in writing

or electronically as described below; or

(b) grant a proxy in writing to another

shareholder or other third party.

Proxies to the independent proxy must be

mailed to and received by our transfer agent, Computershare Trust Company N.A. by 12:00 pm EST / 6:00 pm Swiss time on 23 April

2018. Proxies received after such time will not be considered. Please do not send your proxy card directly to the independent proxy.

The login information for electronic instructions

is set forth on the proxy form. Electronic instructions must be received no later than 11:59 pm EST on 23 April 2018 / 5:59 am

Swiss time on 24 April 2018.

Shareholders that have granted a proxy

to the independent proxy, in writing or electronically, may not vote their shares at the Extraordinary General Meeting.

3 Registration as Shareholder with Voting

Instructions on how a "street name"

holder may become a holder of record are available in the "Investors" section of our website (www.acimmune.com). Between

5:00 pm EST / 11:00 pm Swiss time on 13 March 2018 and 12:00 pm EST / 6:00 pm Swiss time on 27 April 2018, no new shareholder

will be registered for voting purposes. Computershare Trust Company N.A. will continue to register transfers of shares in the share

register in its capacity as transfer agent.

4 Trading Restrictions

The registration of shareholders for voting

purposes does not impact trading of AC Immune shares held by registered shareholders before, during or after the Extraordinary

General Meeting. Shareholders selling their shares in AC Immune prior to the meeting are excluded from voting.