X0306 4 2019-06-12 0 0001731831 Eidos Therapeutics, Inc. EIDX 0001262325 AGUIAR ERIC C/O EIDOS THERAPEUTICS, INC. 101 MONTGOMERY STREET, SUITE 2550 SAN FRANCISCO CA 94104 1 0 1 0 Stock Option (right to buy) 30.87 2019-06-12 4 A 0 21528 0.00 A 2029-06-11 Common Stock 21528 21528 D The shares subject to this option shall vest and become exercisable in a single installment on the earlier of (i) the first anniversary of the grant date, so that all of the underlying shares shall be vested on June 12, 2020, or (ii) the Issuer's next annual meeting of stockholders, in each case subject to the Reporting Person's continued service with the Issuer through the vesting date. This option is subject to full acceleration of vesting with respect to all then-unvested shares upon the consummation of a Sale Event (as defined in the Issuer's 2018 Stock Option and Incentive Plan, as amended). /s/ Franco Valle, as Attorney-in-Fact 2019-06-13