MMMMMMMMMMMM . PRELIMINARY MMMMMMMMMMMMMMM C123456789 Idera Pharmaceuticals, Inc. 000004 000000000.000000 ext 000000000.000000 ext 000000000.000000 ext 000000000.000000 ext 000000000.000000 ext 000000000.000000 ext ENDORSEMENT_LINE______________ SACKPACK_____________ Electronic Voting Instructions Available 24 hours a day, 7 days a week! Instead of mailing your proxy, you may choose one of the voting methods outlined below to vote your proxy. VALIDATION DETAILS ARE LOCATED BELOW IN THE TITLE BAR. Proxies submitted by the Internet or telephone must be received by 11:59 p.m., Eastern Time, on July 9, 2018. MR A SAMPLE DESIGNATION (IF ANY) ADD 1 ADD 2 ADD 3 ADD 4 ADD 5 ADD 6 Vote by Internet • Go to www.investorvote.com/IDRA • Or scan the QR code with your smartphone • Follow the steps outlined on the secure website Vote by telephone • Call toll free 1-800-652-VOTE (8683) within the USA, US territories & Canada on a touch tone telephone • Follow the instructions provided by the recorded message Using a black ink pen, mark your votes with an X as shown in this example. Please do not write outside the designated areas. q IF YOU HAVE NOT VOTED VIA THE INTERNET OR TELEPHONE, FOLD ALONG THE PERFORATION, DETACH AND RETURN THE BOTTOM PORTION IN THE ENCLOSED ENVELOPE. q + ForAgainst Abstain Proposals — The Board of Directors recommends a vote FOR Proposals 1 and 2. For Against Abstain 1. Proposal 1 — The Merger Proposal: To adopt the Agreement and Plan of Merger, dated as of January 21, 2018, by and among BioCryst Pharmaceuticals, Inc., Idera Pharmaceuticals, Inc. (“Idera”), Nautilus Holdco, Inc., Island Merger Sub, Inc. and Boat Merger Sub, Inc. 2. Proposal 2 — The Merger-Related Compensation Proposal: To approve, on a non-binding advisory basis, the compensation that may become payable to Idera’s named executive officers that is based on or otherwise relates to the mergers. Non-Voting Items Change of Address — Please print new address below. Comments — Please print your comments below. Authorized Signatures — This section must be completed for your vote to be counted. — Date and Sign Below Please sign this proxy exactly as your name appears hereon. Joint owners should each sign personally. Trustees and other fiduciaries should indicate the capacity in which they sign. If a corporation or partnership, this signature should be that of an authorized officer who should state his or her title. Date (mm/dd/yyyy) — Please print date below. Signature 1 — Please keep signature within the box. Signature 2 — Please keep signature within the box. MMMMMMMC 1234567890 J N T MR A SAMPLE (THIS AREA IS SET UP TO ACCOMMODATE 140 CHARACTERS) MR A SAMPLE AND MR A SAMPLE AND MR A SAMPLE AND MR A SAMPLE AND MR A SAMPLE AND MR A SAMPLE AND MR A SAMPLE AND MR A SAMPLE AND + 1 U P X3 7 4 7 1 6 1 02SXOE MMMMMMMMM C B A Special Meeting Proxy Card1234 5678 9012 345 X IMPORTANT SPECIAL MEETING INFORMATION
. q IF YOU HAVE NOT VOTED VIA THE INTERNET OR TELEPHONE, FOLD ALONG THE PERFORATION, DETACH AND RETURN THE BOTTOM PORTION IN THE ENCLOSED ENVELOPE. q Proxy — IDERA PHARMACEUTICALS, INC. PROXY SOLICITED BY THE BOARD OF DIRECTORS Special Meeting of Stockholders — July 10, 2018 Those signing on the reverse side, revoking all prior proxies, hereby appoint(s) Mr. Vincent J. Milano and Mr. Louis J. Arcudi, III, or each or any of them with full power of substitution, as proxies for those signing on the reverse side to act and vote all shares of stock of Idera which the undersigned would be entitled to vote if personally present at the Special Meeting of Stockholders of Idera (the “Meeting”) and at any adjournment or postponement thereof as indicated upon all matters referred to on the reverse side and described in the joint proxy statement / prospectus for the Meeting, and, in their discretion, upon any other matters which may properly come before the Meeting. Attendance of the undersigned at the Meeting or at any adjournment or postponement thereof will not be deemed to revoke this proxy unless those signing on the reverse side shall revoke this proxy in writing. THIS PROXY WHEN PROPERLY EXECUTED WILL BE VOTED IN THE MANNER DIRECTED BY THE STOCKHOLDER(S) SIGNING THE REVERSE SIDE AND IN THE DISCRETION OF THE PROXIES UPON ANY OTHER MATTERS WHICH PROPERLY COME BEFORE THE MEETING. IF NO INDICATION IS MADE, THE PROXIES SHALL VOTE “FOR” PROPOSALS NUMBERED 1 AND 2. PLEASE VOTE, DATE AND SIGN ON OTHER SIDE AND RETURN PROMPTLY IN ENCLOSED ENVELOPE. YOUR VOTE IS IMPORTANT. PLEASE VOTE TODAY.
