13D Filings
iTeos Therapeutics, Inc.
Initial Filing
Ownership

27.90%

Total Shares

10,688,978

Issuer CIK

1808865

CUSIP

46565G104

Event Date

May 14, 2025

Accepted

May 16, 2025, 07:22 PM

Reporting Persons (3)
Joint Filing

This is a joint filing. The reported shares may overlap between reporting persons and should not be summed.

NameType% of ClassAggregateSole VotingShared Voting
EcoR1 Capital, LLC
Investment Adviser
27.90%10,688,978010,688,978
Oleg Nodelman
Individual
27.90%10,688,978010,688,978
EcoR1 Capital Fund Qualified, L.P.
Partnership
26.20%10,020,210010,020,210
Disclosure Items (7)

Security Title

Common Stock

Issuer Name

iTeos Therapeutics, Inc.

Issuer Address

321 Arsenal Street, Watertown, MA, 02472

Filing Persons

The reporting persons are: EcoR1 Capital, LLC, a Delaware limited liability company ("EcoR1") EcoR1 Capital Fund Qualified, L.P., a Delaware limited partnership ("Qualified Fund") Oleg Nodelman Qualified Fund is filing this statement jointly with the other reporting persons, but not as a member of a group, and it expressly disclaims membership in a group. In addition, the filing of this Schedule 13D on behalf of Qualified Fund should not be construed as an admission that it is, and it disclaims that it is, a beneficial owner, as defined in Rule 13d-3 under the Act, of any securities covered by this Schedule 13D. Each reporting person also disclaims beneficial ownership of the securities reported herein except to the extent of that person's pecuniary interest therein.

Business Address

357 Tehama Street #3, San Francisco, CA 94103

Principal Occupation

EcoR1 is an investment adviser to investment funds, including Qualified Fund (collectively, the "Funds"). EcoR1 is the general partner of the Funds. Mr. Nodelman is the manager and control person of EcoR1.

Convictions

During the last five years, none of the reporting persons was a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

Citizenship

For citizenship of the reporting persons, see Item 6 of each reporting person's cover page.

The Funds used their working capital to purchase the Issuer's Common Stock. The amount of funds used in purchasing the Issuer's Common Stock was as follows: EcoR1 Capital Fund Qualified, L.P.: $76,292,761.21 EcoR1 Capital Fund, L.P.: $5,092,225.41

All of the Common Stock of the Issuer reported on this Schedule 13D was acquired in the ordinary course of business by the reporting persons for investment purposes. The reporting persons have no present plans or proposals that relate to or would result in any of the actions described in Item 4(a) through (j) of Schedule 13D. The reporting persons may evaluate on a continuing basis the investment in the Issuer and may, from time to time, acquire or dispose of Common Stock of the Issuer. Any such acquisitions or dispositions will depend upon (i) the price and availability of the Issuer's securities; (ii) subsequent developments concerning the Issuer's business and prospects and the industry in which the Issuer operates; (iii) investment policies of the reporting persons; (iv) other investment opportunities available to the reporting persons; (v) general market and economic conditions; (vi) tax considerations; and (viii) such other factors as the reporting persons may deem relevant. Any such acquisitions or dispositions may be made, subject to applicable law, in open market transactions.

Percentage of Class

Aggregate number of shares beneficially owned by the reporting persons: EcoR1: 10,688,978 Oleg Nodelman: 10,688,978 Qualified Fund: 10,020,210 Aggregate percentage of the class of Common Stock beneficially owned by the reporting persons: EcoR1: 27.9% Oleg Nodelman: 27.9% Qualified Fund: 26.2%

Number of Shares

Number of shares as to which the each reporting person has: (i) Sole power to vote or to direct the vote: EcoR1: 0 Oleg Nodelman: 0 Qualified Fund: 0 (ii) Shared power to vote or to direct the vote: EcoR1: 10,688,978 Oleg Nodelman: 10,688,978 Qualified Fund: 10,020,210 (iii) Sole power to dispose or to direct the disposition of: EcoR1: 0 Oleg Nodelman: 0 Qualified Fund: 0 (iv) Shared power to dispose or to direct the disposition of: EcoR1: 10,688,978 Oleg Nodelman: 10,688,978 Qualified Fund: 10,020,210

Transactions

The reporting persons engaged in the following transactions in the Issuer's Common Stock in the 60 days preceding the date of this Schedule 13D: On 4/15/2025, the Funds purchased 14,594 shares of the Issuer's Common Stock for the price of $6.0727 per share. Qualified Fund purchased 13,683 of these shares. On 4/16/2025, the Funds purchased 313,159 shares of the Issuer's Common Stock for a dollar-weighted average price of $6.1032 per share. Qualified Fund purchased 293,618 of these shares. On 4/17/2025, the Funds purchased 359,017 shares of the Issuer's Common Stock for a dollar-weighted average price of $6.4137 per share. Qualified Fund purchased 336,613 of these shares. On 4/21/2025, the Funds purchased 198,538 shares of the Issuer's Common Stock for a dollar-weighted average price of $6.5915 per share. Qualified Fund purchased 186,147 of these shares. On 4/22/2025, the Funds purchased 315,097 shares of the Issuer's Common Stock for a dollar-weighted average price of $7.3271 per share. Qualified Fund purchased 295,435 of these shares. On 4/23/2025, the Funds purchased 50,864 shares of the Issuer's Common Stock for a dollar-weighted average price of $7.1130 per share. Qualified Fund purchased 47,691 of these shares. On 4/24/2025, the Funds purchased 24,361 shares of the Issuer's Common Stock for the price of $7.4221 per share. Qualified Fund purchased 22,845 of these shares. On 4/25/2025, the Funds purchased 91,595 shares of the Issuer's Common Stock for a dollar-weighted average price of $7.3569 per share. Qualified Fund purchased 85,879 of these shares. On 4/28/2025, the Funds purchased 106,223 shares of the Issuer's Common Stock for a dollar-weighted average price of $7.2038 per share. Qualified Fund purchased 99,594 of these shares. On 4/29/2025, the Funds purchased 42,498 shares of the Issuer's Common Stock for a dollar-weighted average price of $6.7550 per share. Qualified Fund purchased 39,842 of these shares. On 4/30/2025, the Funds purchased 305,326 shares of the Issuer's Common Stock for a dollar-weighted average price of $7.2285 per share. Qualified Fund purchased 286,274 of these shares. On 5/1/2025, the Funds purchased 455,139 shares of the Issuer's Common Stock for a dollar-weighted average price of $7.4706 per share. Qualified Fund purchased 426,645 of these shares. On 5/2/2025, the Funds purchased 38,012 shares of the Issuer's Common Stock for the price of $7.7499 per share. Qualified Fund purchased 35,633 of these shares. On 5/5/2025, the Funds purchased 12,612 shares of the Issuer's Common Stock for the price of $7.1534 per share. Qualified Fund purchased 11,823 of these shares. On 5/6/2025, the Funds purchased 86,183 shares of the Issuer's Common Stock for a dollar-weighted average price of $6.6519 per share. Qualified Fund purchased 80,788 of these shares. On 5/7/2025, the Funds purchased 127,548 shares of the Issuer's Common Stock for a dollar-weighted average price of $6.3213 per share. Qualified Fund purchased 119,563 of these shares. On 5/8/2025, the Funds purchased 115,874 shares of the Issuer's Common Stock for a dollar-weighted average price of $6.64 per share. Qualified Fund purchased 108,621 of these shares. On 5/9/2025, the Funds purchased 12,652 shares of the Issuer's Common Stock for the price of $6.6601 per share. Qualified Fund purchased 11,859 of these shares. On 5/12/2025, the Funds purchased 630,708 shares of the Issuer's Common Stock for the price of $6.8018 per share. Qualified Fund purchased 591,226 of these shares. On 5/13/2025, the Funds purchased 1,930,000 shares of the Issuer's Common Stock for the price of $8.10 per share. Qualified Fund purchased 1,809,182 of these shares. On 5/14/2025, the Funds purchased 1,658,978 shares of the Issuer's Common Stock for a dollar-weighted average price of $7.4055 per share. Qualified Fund purchased 1,555,127 of these shares. On 5/15/2025, the Funds purchased 3,300,000 shares of the Issuer's Common Stock for the price of $8.00 per share. Qualified Fund purchased 3,093,422 of these shares.

Shareholders

Not applicable.

Date of 5% Ownership

Not applicable.

EcoR1 is the investment adviser to its clients pursuant to investment management agreements or limited partnership agreements providing to EcoR1 the authority, among other things, to invest the funds of such clients in stock, to vote and dispose of stock and to file this statement on behalf of such clients. Pursuant to such limited partnership agreements, EcoR1 is entitled to allocations based on assets under management and realized and unrealized gains. Pursuant to such investment management agreements, EcoR1 is entitled to fees based on assets under management and realized and unrealized gains.

Exhibit 99.1 Agreement Regarding Joint Filing of Statement on Schedule 13D or 13G.