X0306 4 2023-03-02 0001559053 PROTHENA CORP PUBLIC LTD CO PRTA 0001457013 Nguyen Tran C/O PROTHENA BIOSCIENCES INC 331 OYSTER POINT BOULEVARD SOUTH SAN FRANCISCO CA 94080 true Chief Strategy Officer and CFO Stock Option (Right to Buy) 52.97 2023-03-02 4 A 0 48000 0 A 2033-03-02 Ordinary Shares 48000 48000 D The shares subject to the option will vest and become exercisable as to 25% of the total number of shares subject to the option on March 2, 2024 and with respect to 1/48th of the total number of shares subject to the option in successive, equal monthly installments on each monthly anniversary thereafter, subject to the Reporting Person's continued employment with the Issuer on each such vesting date. The Reporting Person holds options that give him the right to acquire an aggregate of 911,837 shares at exercise prices ranging from $6.73 to $52.97, of which 731,837 are currently exercisable, and 180,000 are currently unexercisable but vest over time, subject to the Reporting Person's continued employment with the Issuer on each applicable vesting date of each option award. Certain of these options are subject to an order regarding the separation of assets in accordance with a divorce settlement agreement. /s/ Michael Malecek, as Attorney in Fact for Tran B. Nguyen 2023-03-03