UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

(Rule 13d-101)

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT

TO § 240.13d-1(a) AND AMENDMENTS THERETO FILED PURSUANT TO

§ 240.13d-2(a)

(Amendment No. 3)¹

Enzo Biochem, Inc.

(Name of Issuer)

Common Stock, par value $0.01 per share

(Title of Class of Securities)

294100102

(CUSIP Number)

BRADLEY L. RADOFF

2727 Kirby Drive

Unit 29L

Houston, Texas 77098

STEVE WOLOSKY

RYAN NEBEL

OLSHAN FROME WOLOSKY LLP

1325 Avenue of the Americas

New York, New York 10019

(212) 451-2300

(Name, Address and Telephone Number of Person

Authorized to Receive Notices and Communications)

January 3, 2022

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box ¨.

Note:  Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits.  See § 240.13d-7 for other parties to whom copies are to be sent.

1              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 (“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).

The following constitutes Amendment No. 3 to the Schedule 13D filed by the undersigned (“Amendment No. 3”). This Amendment No. 3 amends the Schedule 13D as specifically set forth herein.

Item 2 is hereby amended to add the following:

In connection with the entry into the Cooperation Agreement, as defined and described in Item 4 below, Lorrie A. Carr is no longer a member of the Section 13(d) group and shall cease to be a Reporting Person immediately upon the filing of this Amendment No. 3 to the Schedule 13D. The remaining Reporting Persons will continue filing statements on Schedule 13D with respect to their beneficial ownership of securities of the Issuer to the extent required by applicable law. Each of the remaining Reporting Persons is party to the Joint Filing Agreement, as further described in Item 6 below.

Item 4 is hereby amended to add the following:

On January 3, 2022, Bradley L. Radoff and the Radoff Foundation (together, the “Radoff Group”) entered into a Cooperation Agreement (the “Cooperation Agreement”) with the Issuer. Pursuant to the Cooperation Agreement, the Issuer agreed, among other things, to immediately appoint Hamid Erfanian and Mr. Radoff to the Board of Directors (the “Board”) as Class I directors with terms expiring at the Issuer’s upcoming 2021 annual meeting of shareholders (the “2021 Annual Meeting”), whereat they will be nominated for re-election, in place of Dov Perlysky and Rebecca Fischer, who each resigned from the Board on January 3, 2022. Mr. Radoff was also appointed as the Chairman of the Audit Committee and as a member of the Nominating/ Governance Committee and Compensation Committee. In addition, at the 2021 Annual Meeting the Issuer will propose an amendment to its Charter and seek shareholder approval to declassify the Board such that, if passed, directors standing for election at and subsequent to the 2021 Annual Meeting will stand for election to one-year terms (the “Declassification Proposal”).

Pursuant to the Cooperation Agreement, the Radoff Group withdrew its nomination of director candidates for election to the Board at the 2021 Annual Meeting and is subject to certain customary standstill restrictions from the date of the Cooperation Agreement until the earlier of (i) 30 days prior to the deadline for the submission of shareholder nominations for the Issuer’s 2022 annual meeting of shareholders, or (y) 120 days prior to the first anniversary of the 2021 Annual Meeting (the “Standstill Period”). During the Standstill Period, the Radoff Group also agreed to vote its Shares (a) in favor of all directors nominated by the Board for election, (b) in favor of the Declassification Proposal and (c) otherwise in accordance with the Board’s recommendations with respect to any other matter presented to shareholders of the Issuer; provided, however, that in the event Institutional Shareholder Services Inc. (“ISS”) or Glass Lewis & Co., LLC (“Glass Lewis”) recommends otherwise with respect to any proposals (other than the election of directors or the Declassification Proposal), the Radoff Group shall be permitted to vote in accordance with ISS’s or Glass Lewis’ recommendation; provided, further, that the Radoff Group shall be permitted to vote in its sole discretion with respect to any publicly announced proposals relating to a merger, acquisition, disposition of all or substantially all of the assets of the Issuer or other business combination involving the Issuer requiring a vote of shareholders of the Issuer. During the Standstill Period, the Radoff Group has also agreed not to acquire beneficial ownership of more than 9.9% of the outstanding Shares.

The foregoing description of the Cooperation Agreement does not purport to be complete and is qualified in its entirety by reference to the Cooperation Agreement, which is attached as Exhibit 99.1 hereto and is incorporated herein by reference.

Item 6 is hereby amended to add the following:

On January 3, 2022, the Radoff Group and the Issuer entered into the Cooperation Agreement as defined and described in Item 4 above and attached as Exhibit 99.1 hereto.

On January 3, 2022, the Reporting Persons entered into a Joint Filing Agreement in which the Reporting Persons who will remain Reporting Persons subsequent to this Amendment No. 3 to the Schedule 13D agreed to the joint filing on behalf of each of them of statements on Schedule 13D with respect to the securities of the Issuer to the extent required by applicable law. A copy of the Joint Filing Agreement is attached hereto as Exhibit 99.2 and is incorporated herein by reference.

Item 7 is hereby amended to add the following exhibits:

SIGNATURES

After reasonable inquiry and to the best of their knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.

Dated: January 4, 2022