X0306 4 2019-04-23 0 0001423824 ALDER BIOPHARMACEUTICALS INC ALDR 0001737613 Lavelle Erin 11804 NORTH CREEK PARKWAY SOUTH BOTHELL WA 98011 0 1 0 0 Chief Operating Officer Common Stock 2019-04-23 4 A 0 5842 0.00 A 5842 D Common Stock 2019-04-25 4 S 0 1434 13.6676 D 4408 D On August 13, 2018, the Reporting Person was granted restricted stock units which represented a contingent right to receive a maximum of 17,526 shares of Issuer's Common Stock (the "RSU"). Up to 5,842 shares subject to the RSU vest upon obtaining acceptance by the U.S. Food and Drug Administration (or any successor entity thereto) (the "FDA") of the first Biologics License Application submitted to the FDA by the Company or an affiliate seeking approval for the commercial sale and marketing of eptinezumab in the United States for review and certification by the Issuer's Compensation Committee that the achievement of such milestone had been achieved (the "FDA Filing Milestone") and the remaining shares subject to the RSU vest upon certain other performance criteria. On April 23, 2019, the Issuer's Compensation Committee certified that the FDA Milestone had been achieved, resulting in the vesting of 5,842 shares subject to the RSU. Represents the number of shares sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of the RSU. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $13.6676 to $13.67, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote 3 to this Form 4. /s/ Alan Hambelton, Attorney-in-Fact 2019-04-25