UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM 20-F/A

(Amendment No. 1)



(Mark One)



| | ☐ | REGISTRATION STATEMENT PURSUANT TO SECTION 12(b) OR (g) OF THE SECURITIES EXCHANGE ACT OF 1934
| | - | ----------------------------------------------------------------------------------------------



OR



| | ☒ | ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934for the fiscal year ended December 31, 2018
| | - | -------------------------------------------------------------------------------------------------------------------------------



OR



| | ☐ | TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
| | - | ----------------------------------------------------------------------------------------



OR



| | ☐ | SHELL COMPANY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934Date of event requiring this shell company report
| | - | --------------------------------------------------------------------------------------------------------------------------------------------



Commission file number: 001-37891



AC IMMUNE SA(Exact name of Registrant as specified in its charter)



Switzerland(Jurisdiction of incorporation)



EPFL INNOVATION PARKBuilding B1015 LausanneSwitzerland(Address of principal executive offices)



Andrea PfeiferTel: +41 21 345 91 21EPFL INNOVATION PARKBuilding B1015 LausanneSwitzerland(Name, Telephone, E-mail and/or Facsimile number and Address of Company Contact Person)



Copies to:



|Richard D. Truesdell, Jr.Derek J. DostalDavis Polk & Wardwell LLP450 Lexington AvenueNew York, NY 10017(212) 450-4000
|---------------------------------------------------------------------------------------------------------------------



Securities registered or to be registered
pursuant to Section 12(b) of the Act:



|Title
of each class                             | Name
of each exchange on which registered
|----------------------------------------------- | -----------------------------------------
|Common Shares, nominal value CHF 0.02 per share | The Nasdaq Global Market                 



Securities registered or to be registered
pursuant to Section 12(g) of the Act:



None



Securities for which there is a reporting
obligation pursuant to Section 15(d) of the Act:



None



Indicate the number of outstanding shares of each of the issuer’s
classes of capital stock or common stock as of the close of the period covered by the annual report.



Common shares: 67,562,333



Indicate by check mark if the registrant is a well-known seasoned
issuer, as defined in Rule 405 of the Securities Act.



☐
Yes    ☒ No



If this report is an annual or transition report, indicate by
check mark if the registrant is not required to file reports pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934.



☐
Yes    ☒ No



Indicate by check mark whether the registrant (1) has filed
all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months
(or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements
for the past 90 days.



☒
Yes    ☐ No



Indicate by check mark whether the registrant has submitted
electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this
chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).



☒
Yes    ☐ No



Indicate by check mark whether the registrant is a large accelerated
filer, an accelerated filer, a non-accelerated filer, or an emerging growth company. See definition of “large accelerated
filer,” “accelerated filer,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.



|Large accelerated filer ☐ | Accelerated filer ☒ | Non-accelerated filer ☐  
|------------------------- | ------------------- | -------------------------
|                          |                     | Emerging growth company ☒



Indicate by check mark which basis of accounting the registrant
has used to prepare the financial statements included in this filing:



|US GAAP ☐ | International Financial Reporting Standards as issued by the International Accounting Standards Board ☒ | Other ☐
|--------- | ------------------------------------------------------------------------------------------------------- | -------



If “Other” has been checked in response to the previous
question indicate by check mark which financial statement item the registrant has elected to follow.



☐
Item 17    ☐ Item 18



If this is an annual report, indicate by check mark whether
the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).



☐
Yes    ☒ No









Explanatory Note



This Amendment No. 1 (this “Amendment”)
to our annual report on Form 20-F for the fiscal year ended December 31, 2018 (the “Form 20-F”) filed on March 21,
2019 (the “Original Filing Date”), is being filed solely to replace Exhibit 4.14 with the attached Exhibit 4.14 to
reflect amendments to paragraph 4(a) of the Instructions as to Exhibits of Form 20-F, governing redaction of confidential information
in material contracts, which became effective as of April 2, 2019.



In addition, the Company is including
in this Amendment currently dated certifications from its Chief Executive Officer and Chief Financial Officer pursuant to
Rule 13a-14 of the Securities Exchange Act of 1934 as Exhibits 12.1 and 12.2, respectively. Because no financial statements
have been included in this Form 20-F/A, paragraph 3 of the certifications have been omitted.



Except for the revised Exhibit, this Amendment
does not amend any other information set forth in the Form 20-F. This Amendment speaks as of the Original Filing Date, does not
reflect any events that may have occurred subsequent to the Original Filing Date and does not modify or update in any way any
disclosures made in the Form 20-F.









ITEM 19. Exhibits



(a) The following documents are filed as
part of this Amendment to the Annual Report on Form 20-F:



|4.14*† | License Agreement between AC Immune SA and Eli Lilly and Company, dated December 11, 2018
|------ | -----------------------------------------------------------------------------------------
|12.1*  | Certification of Andrea Pfeifer pursuant to 17 CFR 240.13a-14(a)                         
|12.2*  | Certification of Joerg Hornstein pursuant to 17 CFR 240.13a-14(a).                       










| | * | Filed herewith.                                                                                                                                                     
| | - | --------------------------------------------------------------------------------------------------------------------------------------------------------------------
| | † | Portions of this exhibit have been omitted because they are both (i) not material and (ii) would likely cause competitive harm to the Company if publicly disclosed.









Signatures



The registrant hereby certifies that it
meets all of the requirements for filing on Form 20-F and this Amendment No. 1 thereto, and that it has duly caused and authorized
the undersigned to sign this Amendment No. 1 to the Annual Report on its behalf.



| | AC IMMUNE SA
| | ------------



|Date: April 19, 2019 |    
|-------------------- | ---
|                     | By:
|                     |    
|                     |    



| | By: | /s/ Joerg Hornstein
| | --- | -------------------
| |     | Name:              
| |     | Title: