X0508 4/A 2024-02-02 2024-02-02 0 0000874015 IONIS PHARMACEUTICALS INC IONS 0001838539 Schneider Eugene C/O IONIS PHARMACEUTICALS 2855 GAZELLE CT CARLSBAD CA 92010 0 1 0 0 EVP, Chf Clinical Develop Ofcr 0 Common Stock 2024-02-02 4 S 0 2106 49.59 D 47659 D The original Form 4 filed on February 2, 2024 reported 2,071 restricted stock units sold by the reporting person which has been revised by this amendment to reflect the actual amount of shares sold and beneficially owned by Mr. Schneider. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $49.58 to $49.60 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. Patrick R. O'Neil, attorney-in-fact For: Eugene Schneider 2024-09-04