X0508 4 2025-03-10 0001850119 Century Therapeutics, Inc. IPSC 0002001162 Pfeiffenberger Brent C/O CENTURY THERAPEUTICS, INC. 25 N 38TH STREET, 11TH FLOOR PHILADELPHIA PA 19104 1 1 0 0 President and CEO 0 Common Stock 2025-03-10 4 S 0 2235 0.615 D 1190310 D Common Stock 2025-03-11 4 A 0 521500 0 A 1711810 D Stock Option (right to buy) 0.601 2025-03-11 4 A 0 521500 0 A 2035-03-11 Common Stock 521500 521500 D The sales reported on this Form 4 represent the number of shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock units ("RSUs"). Such sales were automatic and not at the discretion of the Reporting Person. Reflects the grant of RSUs. Each RSU represents a contingent right to receive one share of Issuer common stock. The RSUs vest 25% on March 11, 2026, with the remaining 75% vesting on a quarterly basis for the three years thereafter, in each case subject the Reporting Person's continued service through the applicable vesting date. The RSUs will be settled on each applicable vesting date in shares of the Issuer's common stock. The option vests 25% on March 11, 2026, with the remaining 75% vesting in 36 equal monthly installments, subject to the Reporting Person's continued service through each applicable vesting date. /s/ Douglas Carr, Attorney-in-Fact 2025-03-12