X0508 4 2026-03-03 0 0000874015 IONIS PHARMACEUTICALS INC IONS 0002037721 Devers Shannon L. 2855 GAZELLE COURT CARLSBAD CA 92010 0 1 0 0 EVP, Chief Human Resources Ofc 1 Common Stock 2026-03-03 4 M 0 3510 37.58 A 26051 D Common Stock 2026-03-03 4 M 0 3760 40.85 A 29811 D Common Stock 2026-03-03 4 M 0 5500 34.69 A 35311 D Common Stock 2026-03-03 4 M 0 6951 32.6 A 42262 D Common Stock 2026-03-03 4 M 0 385 52.87 A 42647 D Common Stock 2026-03-03 4 S 0 14321 79.115 D 28326 D Common Stock 2026-03-03 4 S 0 5030 79.999 D 23296 D Common Stock 2026-03-03 4 S 0 755 80.837 D 22541 D Non-Qualified Stock Option (right to buy) 32.6 2026-03-03 4 M 0 6951 0.0 D 2023-01-03 2032-01-02 Common Stock 6951 928 D Non-Qualified Stock Option (right to buy) 34.69 2026-03-03 4 M 0 5500 0.0 D 2026-01-02 2035-01-01 Common Stock 5500 16500 D Non-Qualified Stock Option (right to buy) 37.58 2026-03-03 4 M 0 3510 0.0 D 2024-01-03 2033-01-02 Common Stock 3510 5744 D Non-Qualified Stock Option (right to buy) 40.85 2026-03-03 4 M 0 3760 0.0 D 2025-09-29 2034-09-28 Common Stock 3760 11280 D Non-Qualified Stock Option (right to buy) 52.87 2026-03-03 4 M 0 385 0.0 D 2020-01-02 2034-01-01 Common Stock 385 8877 D Shares sold pursuant to a Rule 10b5-1 Trading Plan adopted by the reporting person on November 24, 2025. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $78.61 to $79.60 inclusive. The reporting person undertakes to provide to Ionis Pharmaceuticals, Inc. any security holder of Ionis Pharmaceuticals, Inc. 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 ranges set forth in footnote (2) on this Form 4. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $79.68 to $80.675 inclusive. The reporting person undertakes to provide to Ionis Pharmaceuticals, Inc. any security holder of Ionis Pharmaceuticals, Inc. 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 ranges set forth in footnote (3) on this Form 4. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $80.76 to $81.01 inclusive. The reporting person undertakes to provide to Ionis Pharmaceuticals, Inc. any security holder of Ionis Pharmaceuticals, Inc. 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 ranges set forth in footnote (3) on this Form 4. By: Patrick R. O'Neil, attorney-in-fact For: Shannon L. Devers 2026-03-05