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): May 13, 2021

ITEOS THERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

iTeos Therapeutics, Inc.

139 Main Street

Cambridge, Massachusetts 02142

(Address of principal executive offices, including zip code)

(339) 217-0161

(Registrant’s telephone number, including area code)

Not Applicable

(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:

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

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 2.02 Results of Operations and Financial Condition

On May 13, 2021, iTeos Therapeutics, Inc. announced its financial results for the quarter ended March 31, 2021. A copy of the press release issued in connection with the announcement is furnished as Exhibit 99.1 to this Current Report on Form 8-K.

The information in this Form 8-K (including Exhibit 99.1) shall not be deemed “filed” for 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, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

The following exhibit relating to Item 2.02 shall be deemed furnished, and not filed:

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.

Exhibit 99.1

iTeos Reports First Quarter 2021 Financial Results and Provides Business Update

Cambridge, MA and Gosselies, Belgium – May 13, 2021 — iTeos Therapeutics, Inc. (Nasdaq: ITOS), a clinical-stage biopharmaceutical company pioneering the discovery and development of a new generation of highly differentiated immuno-oncology therapeutics for patients, today reported financial results for the first quarter ended March 31, 2021 and provided recent business highlights.

“Our current clinical strategy includes six studies for our two clinical programs in different indications and combinations that are expected to provide meaningful readouts before the end of 2022. In addition to our recent EOS-448 Phase 1 data presentation at AACR, we also continue to advance our adenosine A_2A receptor antagonist, inupadenant, and we look forward to reporting updated data with evidence that expression of the A_2A receptor in tumor biopsy samples is associated with anti-tumor benefit at the upcoming ASCO meeting in June,” said Michel Detheux, PhD, president and chief executive officer of iTeos. “In addition to this progress across our two lead programs, we also remain committed to our ongoing discovery efforts to identify and advance new novel product candidates that could expand our pipeline and continue to serve our mission to improve the lives of people with cancer.”

Program Highlights

EOS-448: EOS-448 is an IgG1 antibody with the ability to engage the Fc gamma receptor (FcyR) and to enhance the anti-tumor response through a multifaceted mechanism.

iTeos and iTeos logo are trademarks of iTeos Therapeutics Inc.

Inupadenant (EOS-850): Designed as a highly selective small molecule antagonist of the adenosine A_2A receptor. Inupadenant is currently in an open-label multi-arm Phase 1/2a clinical trial in adult patients with advanced solid tumors.

Abstract Title: Phase 1 trial of the adenosine A_2A receptor antagonist inupadenant (EOS-850): Update on tolerability, and antitumor activity potentially associated with the expression of the A_2A receptor within the tumor.

Abstract Number: 2562

Preclinical programs: iTeos continues to progress research programs focused on additional targets that address additional pathways of immunosuppression and complement the mechanism of action of A_2AR and TIGIT programs. iTeos expects to nominate an additional product candidate for Investigational New Drug-enabling studies before the end of 2021.

Upcoming Events

First Quarter 2021 Financial Results

iTeos and iTeos logo are trademarks of iTeos Therapeutics Inc.

Conference Call Details:

iTeos Therapeutics will host a conference call and webcast today, Thursday, May 13^th, at 4:30 p.m. ET. To access the live event, please dial the numbers and reference the conference ID listed below. A live audio webcast of the event will also be accessible from the Events page of the Company’s website at https://investors.iteostherapeutics.com/news-and-events/events. The archived webcast will be available approximately two hours after the completion of the event and for 30 days following the call.

Dial-in Numbers:

(833) 607-1661 (US/Canada)

(914) 987-7874 (International)

Conference ID: 6160559

About iTeos Therapeutics, Inc.

iTeos Therapeutics is a clinical-stage biopharmaceutical company pioneering the discovery and development of a new generation of highly differentiated immuno-oncology therapeutics for patients. iTeos Therapeutics leverages its deep understanding of cancer immunology and immunosuppressive pathways to design novel product candidates with the potential to fully restore the immune response against cancer. The Company’s innovative pipeline includes two clinical-stage programs targeting novel, validated immuno-oncology pathways designed with optimized pharmacologic properties for improved clinical outcomes. The initial antibody product candidate, EOS-448, is a high affinity, potent, anti-TIGIT antibody with a functional Fc domain, designed to enhance the anti-tumor response through a multifaceted immune modulatory mechanism. An open-label Phase 1/2a clinical trial of EOS-448 is ongoing in adult cancer patients with advanced solid tumors with preliminary data indicating preliminary clinical activity as a monotherapy and a favorable tolerability profile. The Company is also advancing inupadenant, a next-generation adenosine A_2A receptor antagonist tailored to overcome cancer immunosuppression. iTeos is conducting an open-label multi-arm Phase 1/2a clinical trial of inupadenant in adult cancer patients with advanced solid tumors. Preliminary results indicate encouraging single-agent activity in the dose escalation portion of the trial. iTeos Therapeutics is headquartered in Cambridge, MA with a research center in Gosselies, Belgium.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995 and other federal securities laws, including express or implied statements regarding iTeos’ future expectations, plans and prospects, including statements regarding the Company’s future expectations and plans for presenting clinical data, the anticipated timing of clinical trials and regulatory filings, and the development of product candidates and advancement of clinical programs, which are based on currently available information. All statements other than statements of historical facts contained in this press release, including statements regarding our strategy, future financial condition, future operations, prospects, plans, objectives of management and expected growth, are forward-looking statements. In some cases, you can identify forward-looking statements by terminology such as ‘‘aim,’’ ‘‘anticipate,’’ ‘‘assume,’’ ‘‘believe,’’ ‘‘contemplate,’’ ‘‘continue,’’ ‘‘could,’’ ‘‘design,’’ ‘‘due,’’ ‘‘estimate,’’ ‘‘expect,’’ ‘‘goal,’’ ‘‘intend,’’ ‘‘may,’’ ‘‘objective,’’ ‘‘plan,’’ ‘‘predict,’’ ‘‘positioned,’’ ‘‘potential,’’ ‘‘seek,’’ ‘‘should,’’ ‘‘target,’’ ‘‘will,’’ ‘‘would’’ and other similar expressions that are predictions of or indicate future events and future trends, or the negative of these terms or other comparable terminology and similar expressions that constitute forward-looking statements under the Private Securities Litigation Reform Act of 1995. These forward-looking statements include statements about the initiation, timing, progress and results of our current and future clinical trials and current and future preclinical studies of our product candidates, including our clinical trials of inupadenant, our clinical trials of EOS-448 and of our research and development programs; uncertainties inherent in clinical studies and in the availability and timing of data from ongoing clinical trials; the expected timing of announcing additional product candidates; the enrollment of our ongoing clinical trials; whether interim results from a clinical trial will be predictive of the final results of the trial; whether results from preclinical studies or earlier clinical studies will be predictive of the results of future clinical trials; our ability to successfully establish or maintain collaborations or strategic relationships for our product candidates; the expected timing for submissions for regulatory approval or review by governmental authorities; our financial performance; whether our cash resources

iTeos and iTeos logo are trademarks of iTeos Therapeutics Inc.

will be sufficient to fund our foreseeable and unforeseeable operating expenses and capital expenditure requirements; risks, uncertainties and assumptions regarding the impact of the continuing COVID-19 pandemic on our business, operations, strategies and anticipated timelines, including mitigation efforts and economic effects, including but not limited to our preclinical studies and future clinical trials; and our plans to develop and commercialize our current product candidates and any future product candidates and the implementation of our business model and strategic plans for our business, current product candidates and any future product candidates, and other risks concerning iTeos’ programs and operations that are described in additional detail in our Annual Report on Form 10-K and our other filings made with the Securities and Exchange Commission from time to time. Although our forward-looking statements reflect the good faith judgment of management, these statements are based solely on facts and circumstances currently known to iTeos. As a result, you are cautioned not to rely on these forward-looking statements. Any forward-looking statement made in this press release speaks only as of the date on which it is made. iTeos undertakes no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, the occurrence of certain events or otherwise.

For further information, please contact:

Investor Contacts:

Ryan Baker

iTeos Therapeutics, Inc.

Ryan.Baker@iteostherapeutics.com

Media Contacts: media@iteostherapeutics.com

iTeos and iTeos logo are trademarks of iTeos Therapeutics Inc.