X0206 3 2017-08-23 0 0001492426 Horizon Pharma plc HZNP 0001715283 Mosbrooker Eric C/O HORIZON PHARMA PLC CONNAUGHT HOUSE, 1ST FL, 1 BURLINGTON RD DUBLIN L2 4 IRELAND 0 1 0 0 SVP, Orphan Business Unit Ordinary Shares 1465 D Stock Option (Right to Buy) 16.91 2026-10-31 Ordinary Shares 28233 D Restricted Stock Units (RSU) Ordinary Shares 17741 D Restricted Stock Units (RSU) Ordinary Shares 7500 D 25% of the shares subject to the option vest and become exercisable on the first anniversary of the date of grant (November 1, 2016), and the remaining shares vest in 36 equal monthly installments thereafter. Each restricted stock unit represents a contingent right to receive one ordinary share of the Issuer. The restricted stock units vest 25% annually on each anniversary of the date of grant (November 1, 2016). Each restricted stock unit represents a contingent right to receive one ordinary share of the Issuer. The restricted stock units vest 50% on June 1, 2018 and 50% on June 1, 2019. /s/ Paul W. Hoelscher, Attorney-in-Fact 2017-08-28