UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR
15d-16 UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of September 2025

Commission file number: 001-37891

AC IMMUNE SA

(Exact Name of Registrant as Specified in Its Charter)

EPFL Innovation Park
Building B
1015 Lausanne, Switzerland

(Address of Principal Executive Offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or
Form 40-F.

Form 20-F ☒ Form 40-F ☐

On September 4, 2025, AC Immune SA (“AC Immune”) issued a press release reporting that, following a strategic review by executive management, AC Immune is sharpening its focused investment on its most important assets. These include its three clinical-stage active immunotherapy programs, two of which are in ongoing pharma collaborations, and its most promising small molecule programs targeting NLRP3 and Tau. As a result, AC Immune will reduce its workforce by around 30% and extend its cash for operations to the end of the third quarter of 2027.

A copy of the press release is attached as Exhibit 99.1 to this Report on Form 6-K.

This Report on Form 6-K shall be deemed to be incorporated by reference into the registration statements on Form F-3 (File Nos. 333-227016, 333-249655 and 333-277940) and Form S-8 (File Nos. 333-213865, 333-216539 and 333-233019) of AC Immune SA and to be a part thereof from the date on which this report is filed, to the extent not superseded by documents or reports subsequently filed or furnished.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

AC IMMUNE SA


By:	/s/ Andrea Pfeifer
	Name:	Andrea Pfeifer
	Title:	Chief Executive Officer


By:	/s/ Christopher Roberts
	Name:	Christopher Roberts
	Title:	Chief Financial Officer

Date: September 4, 2025

EXHIBIT INDEX

Exhibit Number	Description
99.1	Press release dated September 4, 2025

AC Immune SA 6-K