8-K

UNITED STATESSECURITIES AND EXCHANGE COMMISSIONWASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Clearside Biomedical, Inc.

(Exact name of Registrant as Specified in Its Charter)

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 5.03 Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year.

On September 10, 2025, Clearside Biomedical, Inc. (the “Company”) filed a Certificate of Amendment to its Amended and Restated Certificate of Incorporation (the “Amendment”) with the Secretary of State of the State of Delaware to effect a one-for-fifteen (1-for-15) reverse stock split (the “Reverse Stock Split”) of its outstanding common stock and a reduction in the total number of authorized shares of its common stock from 400,000,000 to 26,666,666 (the “Shares Reduction”). The Amendment will be effective at 5:00 p.m. Eastern Time on September 12, 2025. A series of alternate amendments to effect (i) a reverse stock split and (ii) a reduction in the total number of authorized shares of the Company’s common stock was approved by the Company’s stockholders at the Company’s Special Meeting of Stockholders held on August 29, 2025, and the specific one-for-fifteen (1-for-15) Reverse Stock Split and corresponding Shares Reduction was subsequently approved by the Company’s board of directors on September 4, 2025.

The Amendment provides that, at the effective time of the Amendment, every fifteen (15) shares of the Company’s issued and outstanding common stock will automatically be combined into one (1) issued and outstanding share of common stock and the authorized shares of the Company’s common stock will be reduced from 400,000,000 to 26,666,666, without any change in par value per share. The Reverse Stock Split will affect all shares of the Company’s common stock outstanding immediately prior to the effective time of the Amendment. As a result of the Reverse Stock Split, proportionate adjustments will be made to the per share exercise price and/or the number of shares issuable upon the exercise or vesting of all stock options issued by the Company and outstanding immediately prior to the effective time of the Amendment, which will result in a proportionate decrease in the number of shares of the Company’s common stock reserved for issuance upon exercise or vesting of such stock options and a proportionate increase in the exercise price of all such stock options. In addition, all outstanding restricted stock unit awards and warrants will be proportionately adjusted, and the number of shares reserved for issuance under the Company’s equity compensation plans immediately prior to the effective time of the Amendment will be reduced proportionately.

No fractional shares will be issued as a result of the Reverse Stock Split. Stockholders of record who would otherwise be entitled to receive a fractional share will receive a cash payment in lieu thereof. The Reverse Stock Split will affect all stockholders proportionately and will not affect any stockholder’s percentage ownership of the Company’s common stock (except to the extent that the Reverse Stock Split results in any stockholder owning only a fractional share).

The Company’s common stock will begin trading on The Nasdaq Capital Market on a split-adjusted basis when the market opens on September 15, 2025. The new CUSIP number for the Company’s common stock following the Reverse Stock Split is 185063203.

The foregoing description is qualified in its entirety by the Amendment, which is filed as Exhibit 3.1 to this Current Report on Form 8-K and is incorporated herein by reference

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

EX-3.1

Exhibit 3.1

CERTIFICATE OF AMENDMENT

TO

AMENDED AND RESTATED CERTIFICATE OF INCORPORATION

OF

CLEARSIDE BIOMEDICAL, INC.

Clearside Biomedical, Inc., a corporation organized and existing under and by virtue of the General Corporation Law of the State of Delaware (the “DGCL”), certifies:

FIRST: The name of the corporation is Clearside Biomedical, Inc. (the “Company”).

SECOND: The Company’s original Certificate of Incorporation was filed on May 26, 2011. The Certificate of Incorporation was last amended and restated by the Sixth Amended and Restated Certificate of Incorporation on June 7, 2016, and last amended by the Certificate of Amendment to the Amended and Restated Certificate of Incorporation on May 30, 2025 (together, the “Certificate”).

THIRD: The Company’s Board of Directors and stockholders, acting in accordance with the provisions of Sections 141 and 242 of the DGCL, adopted resolutions approving the following amendments to the Certificate:

Effective as of the effective time of 5:00 p.m., Eastern Time, on September 12, 2025 (the “Effective Time”), each fifteen (15) shares of the Company’s Common Stock, par value $0.001 per share, issued and outstanding immediately prior to the Effective Time shall, automatically and without any action on the part of the Company or the respective holders thereof, be combined into one (1) share of Common Stock without increasing or decreasing the par value of each share of Common Stock (the “Reverse Split”); provided, however, no fractional shares of Common Stock shall be issued as a result of the Reverse Split and, in lieu thereof, upon receipt after the Effective Time by the exchange agent selected by the Company of a properly completed and duly executed transmittal letter and, where shares are held in certificated form, the surrender of the stock certificate(s) formerly representing shares of pre-Reverse Split Common Stock, any stockholder who would otherwise be entitled to a fractional share of post-Reverse Split Common Stock as a result of the Reverse Split, following the Effective Time (after taking into account all fractional shares of post-Reverse Split Common Stock otherwise issuable to such stockholder), shall be entitled to receive a cash payment (without interest) equal to the fractional share of post-Reverse Split Common Stock to which such stockholder would otherwise be entitled multiplied by the average of the closing sales prices of a share of the Company’s Common Stock (as adjusted to give effect to the Reverse Split) on The Nasdaq Stock Market for each of the five (5) consecutive trading days immediately preceding the date this Certificate of Amendment is filed with the Secretary of State of the State of Delaware. Each stock certificate that, immediately prior to the Effective Time, represented shares of pre-Reverse Split Common Stock shall, from and after the Effective Time, automatically and without any action on the part of the Company or the respective holders thereof, represent that number of whole shares of post-Reverse Split Common Stock into which the shares of pre-Reverse Split Common Stock represented by such certificate shall have been combined (as well as the right to receive cash in lieu of any fractional shares of post-Reverse Split Common Stock as set forth above; provided, however, that each holder of record of a certificate that represented shares of pre-Reverse Split Common Stock shall receive, upon surrender of such certificate, a new certificate representing the number of whole shares of post-Reverse Split Common Stock into which the shares of pre-Reverse Split Common Stock represented by such certificate shall have been combined pursuant to the Reverse Split, as well as any cash in lieu of fractional shares of post-Reverse Split Common Stock to which such holder may be entitled as set forth above. The Reverse Split shall be effected on a record holder-by-record holder basis, such that any fractional shares of post-Reverse Split Common Stock resulting from the Reverse Split and held by a single record holder shall be aggregated.

The second sentence of Article IV of the Certificate is deleted and replaced in its entirety with:

“The total number of shares of all classes of capital stock which the Company shall have authority to issue is thirty six million six hundred sixty six thousand six hundred sixty six (36,666,666) shares, of which twenty six million six hundred sixty six thousand six hundred sixty six (26,666,666) shares shall be Common Stock (the “Common Stock”), each having a par value of one-tenth of one cent ($0.001), and ten million (10,000,000) shares shall be Preferred Stock (the “Preferred Stock”), each having a par value of one-tenth of one cent ($0.001).”

FOURTH: All other provisions of the Certificate will remain in full force and effect.

FIFTH: This Certificate of Amendment has been duly adopted in accordance with the provisions of Section 242 of the DGCL.

SIXTH: This amendment to the Certificate of Incorporation shall be effective on and as of the effective time of 5:00 p.m., Eastern Time, on September 12, 2025.

[Signature Page Follows]

IN WITNESS WHEREOF, this Certificate of Amendment to Amended and Restated Certificate of Incorporation has been executed by a duly authorized officer of the Company on September 10, 2025.