# EDGAR Filing Document

**Accession Number:** 0001587114
**File Stem:** 0000935836-26-000031
**Filing Date:** 2026-1
**Character Count:** 10982
**Document Hash:** ab87c21eab4f104ce41d4e9d99f604f7
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000935836-26-000031.hdr.sgml**: 20260112

**ACCESSION NUMBER**: 0000935836-26-000031

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260112

**FILED AS OF DATE**: 20260112

**DATE AS OF CHANGE**: 20260112

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** NODELMAN OLEG
- **CENTRAL INDEX KEY:** 0001454385

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-43047
- **FILM NUMBER:** 26528204

**MAIL ADDRESS:**
- **STREET 1:** 357 TEHAMA STREET #3
- **CITY:** SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94103
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** EcoR1 Capital, LLC
- **CENTRAL INDEX KEY:** 0001587114

**ORGANIZATION NAME:**
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-43047
- **FILM NUMBER:** 26528205

**BUSINESS ADDRESS:**
- **STREET 1:** 357 TEHAMA STREET #3
- **CITY:** SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94103
- **BUSINESS PHONE:** 415-448-6534

**MAIL ADDRESS:**
- **STREET 1:** 357 TEHAMA STREET #3
- **CITY:** SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94103
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Aktis Oncology, Inc.
- **CENTRAL INDEX KEY:** 0002035832
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 852584233
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 17 DRYDOCK AVENUE
- **STREET 2:** SUITE #17-401
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02210
- **BUSINESS PHONE:** 978-237-4380

**MAIL ADDRESS:**
- **STREET 1:** 17 DRYDOCK AVENUE
- **STREET 2:** SUITE #17-401
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02210

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

## FORM 4

### STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

[ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

[ ] Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>EcoR1 Capital, LLC<br><sub>(Last) (First) (Middle)</sub><br>357 TEHAMA STREET #3<br><sub>(Street)</sub><br>SAN FRANCISCO, CA 94103<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2026-01-12 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director [ ] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>Aktis Oncology, Inc. [ AKTS ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>NODELMAN OLEG<br><sub>(Last) (First) (Middle)</sub><br>357 TEHAMA STREET #3<br><sub>(Street)</sub><br>SAN FRANCISCO, CA 94103<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2026-01-12 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director [ ] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>Aktis Oncology, Inc. [ AKTS ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | 3. Transaction Code (V) | 3. Transaction Code (V) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | Code | V | Amount | (A) or (D) | Price | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| Common Stock | 2026-01-12 |  | C |  | 2270879 | A | <sup>(1)</sup> | 2270879 | I | See Note<sup>(2)</sup> |
| Common Stock | 2026-01-12 |  | C |  | 202862 | A | <sup>(1)</sup> | 202862 | I | See Note<sup>(3)</sup> |
| Common Stock | 2026-01-12 |  | C |  | 128506 | A | <sup>(1)</sup> | 128506 | I | See Note<sup>(4)</sup> |
| Common Stock | 2026-01-12 |  | P |  | 2077779 | A | $18 | 4348658 | I | See Note<sup>(2)</sup> |
| Common Stock | 2026-01-12 |  | P |  | 144443 | A | $18 | 347305 | I | See Note<sup>(3)</sup> |

---

## Table II - Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | 4. Transaction Code (V) | 4. Transaction Code (V) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 6. Date Exercisable and Expiration Date | 6. Date Exercisable and Expiration Date | 7. Title and Amount of Underlying Securities | 7. Title and Amount of Underlying Securities | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| Series A Redeemable Convertible Preferred Stock | <sup>(1)</sup> | 2026-01-12 |  | C |  |  | 9913810 | <sup>(1)</sup> | <sup>(1)</sup> | Common Stock | 2605878 | <sup>(1)</sup> | 0 | I | See note<sup>(2)</sup> |
| Series A Redeemable Convertible Preferred Stock | <sup>(1)</sup> | 2026-01-12 |  | C |  |  | 997299 | <sup>(1)</sup> | <sup>(1)</sup> | Common Stock | 262142 | <sup>(1)</sup> | 0 | I | See note<sup>(3)</sup> |
| Series A Redeemable Convertible Preferred Stock | <sup>(1)</sup> | 2026-01-12 |  | C |  |  | 488891 | <sup>(1)</sup> | <sup>(1)</sup> | Common Stock | 128506 | <sup>(1)</sup> | 0 | I | See note<sup>(4)</sup> |
| Series B Redeemable Convertible Preferred Stock | <sup>(1)</sup> | 2026-01-12 |  | C |  |  | 2397500 | <sup>(1)</sup> | <sup>(1)</sup> | Common Stock | 630191 | <sup>(1)</sup> | 0 | I | See note<sup>(2)</sup> |
| Series B Redeemable Convertible Preferred Stock | <sup>(1)</sup> | 2026-01-12 |  | C |  |  | 102500 | <sup>(1)</sup> | <sup>(1)</sup> | Common Stock | 26942 | <sup>(1)</sup> | 0 | I | See note<sup>(3)</sup> |
| Class A Common Stock | <sup>(5)</sup> | 2026-01-12 |  | C |  | 965190 |  | <sup>(5)</sup> | <sup>(5)</sup> | Common Stock | 965190 | <sup>(1)</sup> | 965190 | I | See note<sup>(2)</sup> |
| Class A Common Stock | <sup>(5)</sup> | 2026-01-12 |  | C |  | 86222 |  | <sup>(5)</sup> | <sup>(5)</sup> | Common Stock | 86222 | <sup>(1)</sup> | 86222 | I | See Note<sup>(3)</sup> |

---

### Footnotes:

(1) The shares of Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock converted into shares of Common Stock and Class A Common Stock on a 3.8044-for-1 basis immediately prior to the closing of the initial public offering of the Issuer's Common Stock for no additional consideration. Each share was immediately exercisable and had no expiration date.

(2) These securities are held by EcoR1 Capital Fund Qualified, L.P. ("Qualified Fund"). EcoR1 Capital, LLC ("EcoR1") may be deemed to indirectly beneficially own them as the investment adviser to and general partner of the fund. Mr. Nodelman may be deemed to indirectly beneficially own them as the control person of EcoR1.

(3) These securities are held by EcoR1 Capital Fund, L.P. ("Capital Fund"). EcoR1 may be deemed to indirectly beneficially own them as the investment adviser to and general partner of the fund. Mr. Nodelman may be deemed to indirectly beneficially own them as the control person of EcoR1.

(4) These securities are held by EcoR1 Venture Opportunity Fund, L.P. ("Venture Fund"). EcoR1 may be deemed to indirectly beneficially own them as the investment adviser to and general partner of the fund. Mr. Nodelman may be deemed to indirectly beneficially own them as the control person of EcoR1.

(5) Each share of Class A Common Stock is convertible into one share of Common Stock at the election of the holder for no additional consideration, subject to a 4.99% beneficial ownership limitation. Each share is immediately exercisable and has no expiration date.

**Remarks:**
EcoR1 is the general partner and investment adviser of private funds, including Qualified Fund, Capital Fund and Venture Fund. Mr. Nodelman is a director of the Issuer and is the manager and controlling owner of EcoR1. The reporting persons are filing this Form 4 jointly, but not as a group, and each expressly disclaims membership in a group within the meaning of Rule 13d-5(b) under the Securities Exchange Act of 1934. The reporting persons disclaim beneficial ownership of the securities reported herein, except to the extent of their respective pecuniary interests therein.

**Signature:** /s/ Oleg Nodelman, Individually, and as Manager of EcoR1 Capital, LLC  
**Date:** 2026-01-12

### Remarks:

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

**Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.**