Ionis Pharmaceuticals (IONS) SC TO-TThird party tender offer statement

Exhibit (a)(1)(iii)

NOTICE OF GUARANTEED DELIVERY

For Tender of Shares of Common Stock

of

AKCEA THERAPEUTICS, INC.

a Delaware corporation

at

$18.15 NET PER SHARE

Pursuant to the Offer to Purchase dated September 14, 2020

by

AVALANCHE MERGER SUB, INC.

a wholly owned subsidiary of

IONIS PHARMACEUTICALS, INC.

This Notice of Guaranteed Delivery, or one substantially in the form hereof, must be used to accept the Offer (as defined below) if (i) certificates representing shares of common stock, par value $0.001 per share (the “Shares”), of Akcea Therapeutics, Inc., a Delaware corporation, are not immediately available, (ii) the procedure for book-entry transfer cannot be completed prior to the expiration of the Offer or (iii) time will not permit all required documents to reach American Stock Transfer & Trust Company, LLC (the “Depository”) prior to the expiration of the Offer. This Notice of Guaranteed Delivery may be delivered by overnight courier or mailed to the Depository. See Section 13 of the Offer to Purchase (as defined below).

The Depository for the Offer is:

FACSIMILE: (718) 234-5001

CONFIRM: (877) 248-6417

The above number is for confirmation of facsimiles only. Do NOT call this number for questions on the Offer. All questions on the Offer should be directed to the Information Agent listed in the Offer to Purchase.

DELIVERY OF THIS NOTICE OF GUARANTEED DELIVERY TO AN ADDRESS OTHER THAN AS SET FORTH ABOVE WILL NOT CONSTITUTE A VALID DELIVERY.

THIS NOTICE OF GUARANTEED DELIVERY IS NOT TO BE USED TO GUARANTEE SIGNATURES. IF A SIGNATURE ON A LETTER OF TRANSMITTAL IS REQUIRED TO BE GUARANTEED BY AN ELIGIBLE INSTITUTION (AS DEFINED IN SECTION 13 OF THE OFFER TO PURCHASE) UNDER THE INSTRUCTIONS THERETO, SUCH SIGNATURE GUARANTEE MUST APPEAR IN THE APPLICABLE SPACE PROVIDED IN THE SIGNATURE BOX ON THE APPROPRIATE LETTER OF TRANSMITTAL.

The Eligible Institution that completes this Notice of Guaranteed Delivery must communicate the guarantee to the Depository and must deliver the Letter of Transmittal (as defined below) or an Agent’s Message (as defined in Section 13 of the Offer to Purchase) and certificates for Shares (or Book-Entry Confirmation, as defined in Section 13 of the Offer to Purchase) to the Depository within the time period shown herein. Failure to do so could result in a financial loss to such Eligible Institution.

Ladies and Gentlemen:

The undersigned hereby tenders to Avalanche Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Ionis Pharmaceuticals, Inc., a Delaware corporation, upon the terms and subject to the conditions set forth in the Offer to Purchase, dated September 14, 2020 (as it may be amended or supplemented from time to time, the “Offer to Purchase”), and the related Letter of Transmittal (as it may be amended or supplemented from time to time, the “Letter of Transmittal” and, together with the Offer to Purchase, the “Offer”), receipt of which is hereby acknowledged, the number of Shares specified below, pursuant to the guaranteed delivery procedure set forth in Section 13 of the Offer to Purchase.

Notice of Guaranteed Delivery

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GUARANTEE

(Not to be used for signature guarantee)

The undersigned, an Eligible Institution, hereby (i) represents that the tender of Shares effected hereby complies with Rule 14e-4 under the Securities Exchange Act of 1934, as amended, and (ii) within TWO (2) Nasdaq trading days after the date hereof, (A) guarantees delivery to the Depository, at one of its addresses set forth above, of certificates representing the Shares tendered hereby, in proper form for transfer, together with a properly completed and duly executed Letter of Transmittal and any other documents required by the Letter of Transmittal or (B) guarantees a Book-Entry Confirmation of the Shares tendered hereby into the Depository’s account at The Depository Trust Company (pursuant to the procedures set forth in Section 13 of the Offer to Purchase), together with a properly completed and duly executed Letter of Transmittal, or an Agent’s Message (defined in Section 13 of the Offer to Purchase) in lieu of such Letter of Transmittal, and any other documents required by the Letter of Transmittal.

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