X0306 4 2019-06-07 1 0001711675 Nightstar Therapeutics plc NITE 0001219871 MOTT DAVID M 1954 GREENSPRING DRIVE SUITE 600 TIMONIUM MD 21093 1 0 1 0 Ordinary Shares 2019-06-07 4 D 0 6662532 25.50 D 0 I See Note 2 Stock Option (Right to Buy) 12.27 2019-06-07 4 D 0 36400 13.23 D 2028-02-27 Ordinary Shares 36400 0 D Stock Option (Right to Buy) 13.57 2019-06-07 4 D 0 21000 11.93 D 2029-01-24 Ordinary Shares 21000 0 D The ordinary shares, nominal value GBP 0.01 per share, of Nightstar Therapeutics plc (the "Issuer") may be represented by American Depositary Shares ("ADSs"). Each ADS represents one ordinary share of the Issuer. The Reporting Person is a manager of NEA 15 GP, LLC, ("NEA 15 GP") which is the sole general partner of NEA Partners 15, L.P. ("NEA Partners 15"). NEA Partners 15 is the sole general partner of New Enterprise Associates 15, L.P. ("NEA 15"), which is the direct beneficial owner of the shares. The Reporting Person disclaims beneficial ownership within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the shares held by NEA 15 in which the Reporting Person has no pecuniary interest. In connection with the acquisition by Tungsten Bidco Limited of the entire issued and to be issued share capital of the Issuer on June 7, 2019 by means of a scheme of arrangement under Part 26 of the UK Companies Act 2006, all stock options were cancelled in exchange for a payment equal to $25.50 with respect to each ordinary share subject to the option award, less the applicable exercise price. Represents the payment per share received in exchange for the cancellation of each option of $25.50, less the applicable exercise price. /s/ Sasha Keough, attorney-in-fact 2019-06-07