X0306 4 2021-05-27 0 0001847903 Centessa Pharmaceuticals plc CNTA 0001826323 Thorell Marella C/O CENTESSA PHARMACEUTICALS PLC 3RD FL., 1 ASHLEY RD, ALTRINCHAM CHESHIRE X0 WA14 2DT UNITED KINGDOM 0 1 0 0 Chief Accounting Officer Share Option (right to buy) 4.11 2021-01-29 4 A 0 58956 0.00 A 2030-09-30 Ordinary Shares 58956 58956 D Share Option (right to buy) 4.87 2021-01-29 4 A 0 9487 0.00 A 2030-12-30 Ordinary Shares 9487 9487 D Share Option (right to buy) 5.84 2021-02-19 4 A 0 208474 0.00 A 2031-02-19 Ordinary Shares 208474 208474 D Share Option (right to buy) 20.00 2021-05-27 4 A 0 137500 0.00 A 2031-05-27 Ordinary Shares 137500 137500 D On May 20, 2021, the Issuer effected a share capital reorganization, which had the effect of a one for two reverse share split of the Issuer's share capital ("Stock Split"). This amount has been adjusted to give effect to the Stock Split. This transaction occurred prior to the effectiveness of the Issuer's registration under Section 12 of the Securities Exchange Act of 1934 and is being reported on Form 4 solely for purposes of compliance with Rule 16a-2(a) under the Securities Exchange Act of 1934, as amended. The securities covered by such transaction were previously included on the Reporting Person's Form 3. 56.25% of the shares subject to such option are vested as of January 29, 2021. The remaining 43.75% of the shares subject to such option shall vest and become exercisable monthly beginning on February 1, 2021. Represents A Ordinary Shares that will be redesignated as Ordinary Shares immediately prior to the closing of the initial public offering. The Ordinary Shares may be represented by American Depositary Shares, each of which currently represents one Ordinary Share. 25% of the shares subject to such option are vested as of January 29, 2021. The remaining 75% of the shares subject to such option shall vest and become exercisable monthly beginning on February 1, 2021. 25% of the shares subject to such option shall vest and become exercisable on February 19, 2022 and the remaining 75% of the shares subject to such option shall vest and become exercisable in 36 monthly installments on the first day of each month thereafter. 25% of the shares subject to such option shall vest and become exercisable on February 1, 2022 and the remaining 75% of the shares subject to such option shall vest and become exercisable in 36 monthly installments on the first day of each month thereafter. /s/ Marella Thorell 2021-06-01