X0609 4 2026-09-23 false 0002035832 Aktis Oncology, Inc. AKTS 0002049427 Czibere Akos false C/O AKTIS ONCOLOGY, INC. 17 DRYDOCK AVENUE, SUITE 17-401 BOSTON MA 02210 false true false false Chief Medical Officer true Common Stock 2026-09-23 4 M false 12500 4.95 A 12500 D Common Stock 2026-09-23 4 S false 5099 20.1947 D 7401 D Common Stock 2026-09-23 4 S false 7401 21.0307 D 0 D Stock Option (Right to Buy) 4.95 2026-09-23 4 M false 12500 0 D 2034-06-30 Common Stock 12500 208718 D The transactions reported herein were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 24, 2026. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $19.6700 to $20.6500, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $20.6700 to $21.5000, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range. 25% of the original number of shares subject to the option vested on July 1, 2025, and 1/48th of the original number of shares subject to the option vested or shall vest in monthly installments thereafter, subject to the Reporting Person's continuous service through each vesting date, inclusive. /s/ Kyle D. Kuvalanka, as Attorney-in-Fact 2026-09-24