SCHEDULE 13G

SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, DC 20549

Under the Securities Exchange Act of 1934
(Amendment No. 1)*

Idera Pharmaceuticals, Inc.

(Name of Issuer)

Common Stock, par value $0.001 per share

(Title of Class of Securities)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

*The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (the “Act”) or otherwise subject to the liabilities of that section of the Act, but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No.  45168K405

(1)    Based on 38,290,889 shares of Common Stock outstanding as of December 31, 2020, as per information received from the Issuer.

(1)    Based on 38,290,889 shares of Common Stock outstanding as of December 31, 2020, as per information received from the Issuer.

CUSIP No.  45168K405  

CUSIP No.  45168K405

Amendment No. 1 to Schedule 13G

This Amendment No. 1 to Schedule 13G amends the previously filed Schedule 13G filed by Baker Bros. Advisors LP (the “Adviser”), Baker Bros. Advisors (GP) LLC (the “Adviser GP”), Julian C. Baker, Felix J. Baker and FBB3 LLC (“FBB3”, and together with the Adviser, the Adviser GP, Julian C. Baker and Felix J. Baker, the “Reporting Persons”). Except as supplemented herein, such statements, as heretofore amended and supplemented, remain in full force and effect.

Idera Pharmaceuticals, Inc.

505 Eagleview Blvd., Suite 212

Exton, Pennsylvania 19341

This Amendment No. 1 is being filed jointly by the Reporting Persons.

The business address of each of the Reporting Persons is:

c/o Baker Bros. Advisors LP

860 Washington Street, 3^rd Floor

New York, NY 10014

(212) 339-5690

The Adviser is a limited partnership organized under the laws of the State of Delaware. The Adviser GP is a limited liability company organized under the laws of the State of Delaware. The citizenship of each of Julian C. Baker and Felix J. Baker is the United States of America. FBB3 is a limited liability company organized under the laws of the state of Delaware.

Common Stock, par value $0.001 per share (“Common Stock”)

45168K405

(a) ¨ Broker or dealer registered under Section 15 of the Exchange Act.

(b) ¨ Bank as defined in section 3(a)(6) of the Exchange Act.

(c) ¨ Insurance company as defined in section 3(a)(19) of the Exchange Act.

(d) ¨ Investment company registered under section 8 of the Investment Company Act of 1940.

(e) x An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E).

(f)  ¨ An employee benefit plan or endowment fund in accordance with Rule 13d-1(b)(1)(ii)(F).

(g) x A parent holding company or control person in accordance with Rule 13d-1(b)(1)(ii)(G).

(h) ¨ A savings association as defined in Section 3(b) of the Federal Deposit Insurance Act.

(i) ¨ A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940.

(j) ¨ Group, in accordance with Rule 13d-1(b)(1)(ii)(J).

Items 5 through 9 and 11 of each of the cover pages to this Amendment No. 1 are incorporated herein reference.

Set forth below is the aggregate number of shares of Common Stock directly held by each of 667, L.P. (“667”) and Baker Brothers Life Sciences, L.P. (“Life Sciences”, and together with 667, the “Funds”), which may be deemed to be indirectly beneficially owned by the Reporting Persons.

The information set forth below is based upon 38,290,889 shares of Common Stock outstanding as of December 31, 2020, as per information received from the Issuer. Such percentage figures are calculated in accordance with Rule 13d-3 under the Securities Exchange Act of 1934, as amended.

Julian. C Baker and Felix J. Baker each hold 21,929 shares of Common Stock. FBB 3 directly holds 10,596 shares of Common Stock.

Dr. Kelvin M. Neu, a full-time employee of the Adviser as of December 31, 2020, and Julian C. Baker, a managing member of the Adviser GP, hold 23,684 and 9,246 shares of Common Stock, respectively, from their previous service on the Board of Directors of the Issuer (the “Board”).

The policy of the Funds and the Adviser does not permit managing members of the Adviser GP or full-time employees of the Adviser to receive compensation for serving as a director of the Issuer and the Funds are instead entitled to the pecuniary interest in the Common Stock received as director compensation. Julian C. Baker and Dr. Neu have no voting or dispositive power and no pecuniary interest in the Common Stock received as compensation for their previous service on the Board. Other than through their control of the Adviser, Felix J. Baker and Julian C. Baker have neither voting nor dispositive power and have no direct pecuniary interest in the Common Stock received as director’s compensation held by Julian C. Baker and Dr. Neu.

The Adviser has voting and investment power over the Common Stock received as director compensation held by Julian C. Baker and Dr. Neu.

In addition, the Funds and certain Reporting Persons directly hold certain series of warrants to purchase Common Stock or various series of convertible preferred stock of the Issuer, options to purchase various series of convertible preferred stock of the Issuer along with warrants of the Issuer, and shares of the Issuer’s convertible preferred stock (such warrants, options and convertible preferred stock, collectively, the “Derivative Securities”) Each of the Derivative Securities does not currently represent beneficial ownership of the Common Stock for the Reporting Persons because either the Derivative Securities or the underlying series of convertible preferred stock of the Issuer are subject to beneficial ownership limitations on exercise or conversion such that the Reporting Persons do not have a present right to acquire shares of Common Stock within 60 days.

The Adviser GP is the sole general partner of the Adviser. Pursuant to the management agreements, as amended, among the Adviser, Life Sciences and 667 and their respective general partners, the Funds respective general partners relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds, and thus the Adviser has completed and unlimited discretion and authority with respect to the Funds’ investments and voting power over investments. Julian C. Baker and Felix J. Baker are also the sole managers of FBB3 and by policy they do not transact in or vote the securities of the Issuer held by FBB3.

If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following [ ]. N/A

N/A

The information in Item 4 is incorporated herein by reference.

N/A

N/A

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

January 29, 2021