FDA trial setback prompts IO Biotech (NASDAQ: IOBT) to cut 50% of jobs

Rhea-AI Filing Summary

IO Biotech, Inc. reported that its board approved a major restructuring and workforce reduction plan to conserve capital and focus on developing Cylembio. The plan will cut approximately 50% of the company’s global workforce.

The company expects to record one-time charges of about $1.0 million to $1.5 million, mainly for severance, continued healthcare, earned vacation and related termination costs, largely in the third quarter of 2025, with payments expected to be completed by the fourth quarter of 2025.

IO Biotech also disclosed that the FDA has recommended it not submit a BLA based on data from the IOB-013 clinical trial, which showed improved progression-free survival for Cylembio plus pembrolizumab but narrowly missed statistical significance. The company plans further discussions with the FDA and European regulators on an additional potential registrational study and possible paths to approval in the United States and European Union.

Positive

• None.

Negative

• FDA setback on Cylembio pathway: FDA recommended IO Biotech not submit a BLA based on IOB-013, whose results narrowly missed statistical significance, delaying potential U.S. approval.
• Large workforce reduction and restructuring: Company is cutting about 50% of its global workforce and recording $1.0 million to $1.5 million in one-time charges, indicating a significant downsizing.

Insights

Biotech equity analyst

FDA feedback and 50% workforce cut mark a significant setback for IO Biotech.

IO Biotech’s restructuring centers on conserving capital around its lead asset, Cylembio, after the IOB-013 trial results were not strong enough for the FDA to support a BLA submission. Cutting approximately 50% of the global workforce is a dramatic move that suggests a narrower operational focus and likely reduced spending outside core programs.

The company expects one-time restructuring charges of $1.0 million to $1.5 million, largely in the third quarter of 2025, with payments finishing by the fourth quarter of 2025. These are modest in dollar terms but signal a strategic reset following the regulatory feedback. The key risk is that progress for Cylembio now depends on designing and executing an additional potential registrational study and aligning with both the FDA and European regulators, with timing and outcomes driven by future discussions.

false 0001865494 0001865494 2025-09-25 2025-09-25

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(D)

OF THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): September 25, 2025

IO BIOTECH, INC.

(Exact name of Registrant as Specified in its Charter)

Delaware		001-41008		87-0909276
(State or other jurisdiction of incorporation)		(Commission File Number)		(IRS Employer Identification No.)

Ole Maaløes Vej 3

DK-2200 Copenhagen N

Denmark

(Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code: +45 7070 2980

N/A

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

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

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Common Stock, par value $0.001 per share		IOBT		The Nasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.05. Costs Associated with Exit or Disposal Activities.

On September 25, 2025, the Board of Directors of IO Biotech, Inc. (the “Company”) approved a restructuring and workforce reduction plan (the “Plan”) to conserve capital to align the Company’s operations with its primary focus of advancing development of Cylembio^® (imsapepimut and etimupepimut, adjuvanted). The Plan is expected to result in a reduction of approximately 50% of the Company’s workforce globally.

In connection with the implementation of the Plan, the Company expects to incur one-time charges and cash expenditures in a range of approximately $1.0 million to $1.5 million, primarily related to employee wages and severance payments, healthcare continuation, earned vacation time and related termination costs.. The Company expects to incur these charges primarily during the third quarter of 2025 and payment of these charges is expected to be completed by the fourth quarter of 2025.

The actual timing and amount of these charges may differ from the Company’s current estimates due to a variety of factors, including the finalization of severance terms, jurisdiction-specific legal requirements, and the pace of transition activities. The Company may also incur additional non-material charges in future periods related to the Plan.

Item 7.01. Regulation FD Disclosure.

On September 29, 2025, the Company issued a press release (the “Press Release”) announcing the Plan and providing an update following the Company’s meeting with the U.S. Food and Drug Administration (the “FDA”).

A copy of the Press Release is attached hereto as Exhibit 99.1 and is incorporated by reference into this Item 7.01 of this Current Report on Form 8-K.

The information contained in this Item 7.01 Current Report on Form 8-K, including Exhibit 99.1 hereto, is being furnished and shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section and shall not be incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.

Item 8.01. Other Events

On September 29, 2025, the Company announced that the FDA has recommended that the Company not submit a BLA based on the data from the IOB-013 clinical trial. As previously announced, in the IOB-013 trial treatment with Cylembio plus pembrolizumab improved progression free survival, but the results narrowly missed statistical significance. The Company plans to continue the dialogue with FDA to align on an efficient path to market for Cylembio, including the design of a potential additional registrational study for Cylembio. The Company also plans to discuss the data from the IOB-13 clinical trial with the European regulators and determine a path to approval in the EU.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

Exhibit Number		Exhibit Description
99.1		IO Biotech, Inc. Press Release, dated as of September 29, 2025
104		Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURES

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 hereunto duly authorized.

				IO BIOTECH, INC.
Date: September 29, 2025				By:		/s/ Mai-Britt Zocca, Ph.D.
				Name:		Mai-Britt Zocca, Ph.D.
				Title:		Chief Executive Officer

FAQ

What restructuring did IO Biotech (IOBT) announce?

IO Biotech’s board approved a restructuring and workforce reduction plan intended to conserve capital and align operations with its primary focus on developing Cylembio.

How many jobs will IO Biotech (IOBT) cut in the restructuring?

The plan is expected to reduce IO Biotech’s global workforce by approximately 50%, representing a substantial downsizing of its operations.

What restructuring charges will IO Biotech (IOBT) incur?

IO Biotech expects one-time charges of about $1.0 million to $1.5 million, mainly for wages, severance, healthcare continuation, earned vacation and related termination costs.

When will IO Biotech (IOBT) record and pay the restructuring costs?

The company expects to incur most of the restructuring charges during the third quarter of 2025, with payments expected to be completed by the fourth quarter of 2025.

What did the FDA recommend regarding IO Biotech’s Cylembio program?

The FDA recommended that IO Biotech not submit a BLA based on data from the IOB-013 clinical trial, even though Cylembio plus pembrolizumab improved progression-free survival but missed statistical significance.

How does IO Biotech (IOBT) plan to move Cylembio forward after the FDA feedback?

IO Biotech plans to continue discussions with the FDA to agree on an efficient path to market, including a potential additional registrational study, and will also discuss IOB-013 data with European regulators to determine an approval path in the EU.