X0306 4 2020-10-12 1 0001662524 AKCEA THERAPEUTICS, INC. AKCA 0001791857 Jenne Kyle C/O AKCEA THERAPEUTICS, INC. 22 BOSTON WHARF ROAD, 9TH FLOOR BOSTON MA 02210 0 1 0 0 Chief Commercial Officer Common Stock 2020-10-12 4 U 0 52012 18.15 D 0 D Stock Option (right to buy) 12.21 2020-10-12 4 D 0 143374 5.94 D 2027-06-04 Common Stock 143374 0 D Stock Option (right to buy) 12.21 2020-10-12 4 D 0 32751 5.94 D 2027-06-04 Common Stock 32751 0 D Stock Option (right to buy) 17.38 2020-10-12 4 D 0 299 0.77 D 2028-01-01 Common Stock 299 0 D Stock Option (right to buy) 17.38 2020-10-12 4 D 0 13701 0.77 D 2028-01-01 Common Stock 13701 0 D Stock Option (right to buy) 12.76 2020-10-12 4 D 0 34200 5.39 D 2030-03-18 Common Stock 34200 0 D This option, which provided that 1/4th of the shares would vest one year after May 15, 2017 and 1/48th of the shares would vest monthly thereafter over the next three years, was cancelled in connection with the merger of the Issuer with a wholly owned subsidiary of Ionis Pharmaceuticals, Inc. in exchange for a cash payment of $851,641.56, representing the difference between the exercise price of the option and the acquisition price of $18.15. This option, which provided that 1/4th of the shares would vest one year after May 15, 2017 and 1/48th of the shares would vest monthly thereafter over the next three years, was cancelled in connection with the merger of the Issuer with a wholly owned subsidiary of Ionis Pharmaceuticals, Inc. in exchange for a cash payment of $194,540.94, representing the difference between the exercise price of the option and the acquisition price of $18.15. This option, which provided that 1/4th of the shares would vest one year after January 2, 2018 and 1/48th of the shares would vest monthly thereafter over the next three years, was cancelled in connection with the merger of the Issuer with a wholly owned subsidiary of Ionis Pharmaceuticals, Inc. in exchange for a cash payment of $230.23, representing the difference between the exercise price of the option and the acquisition price of $18.15. This option, which provided that 1/4th of the shares would vest one year after January 2, 2018 and 1/48th of the shares would vest monthly thereafter over the next three years, was cancelled in connection with the merger of the Issuer with a wholly owned subsidiary of Ionis Pharmaceuticals, Inc. in exchange for a cash payment of $10,549.77, representing the difference between the exercise price of the option and the acquisition price of $18.15. This option, which provided that 1/4th of the shares would vest one year after March 19, 2020 and 1/48th of the shares would vest monthly thereafter over the next three years, was cancelled in connection with the merger of the Issuer with a wholly owned subsidiary of Ionis Pharmaceuticals, Inc. in exchange for a cash payment of $184,338.00, representing the difference between the exercise price of the option and the acquisition price of $18.15. /s/ Joshua F. Patterson, Attorney-in-Fact 2020-10-12