UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Amendment No. 6 to

SCHEDULE 13E-3

Rule 13e-3 Transaction Statement

(Pursuant to Section 13(e) of the Securities Exchange Act of 1934)

COSCIENS Biopharma Inc.

(Name of the Issuer)

COSCIENS Biopharma Inc.

(Name of Persons Filing Statement)

Common Stock, No Par Value per Share

(Title of Class of Securities)

22112H101

(CUSIP Number of Class of Securities)

(Name, Address, and Telephone Number of Person Authorized to Receive Notices and Communication on

Behalf of Person(s) Filing Statement)

This statement is filed in connection with (check the appropriate box):

Check the following box if the soliciting materials or information statement referred to in checking box (a) are preliminary copies: ☐

Check the following box if the filing is a final amendment reporting the results of the transaction: ☒

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of this transaction, passed upon the merits or fairness of this transaction, or passed upon the adequacy or accuracy of the disclosure in this transaction statement on Schedule 13E-3. Any representation to the contrary is a criminal offense.

This Amendment No. 6 (“Amendment No. 6”) to Rule 13e-3 Transaction Statement on Schedule 13E-3 amends and supplements the Rule 13e-3 Transaction Statement on Schedule 13E-3 that was previously filed by COSCIENS Biopharma Inc. (referred to herein as “Company”) with the Securities and Exchange Commission on April 4, 2026, as amended by Amendment No. 1 filed on May 4, 2026, Amendment No. 2 filed on May 8, 2026, Amendment No. 3 filed on May 12, 2026, Amendment No. 4 filed on May 20, 2026, and Amendment No. 5 filed on June 18, 2026 (the “Transaction Statement”).

This Amendment No. 6 is being filed pursuant to Rule 13e-3(d)(3) as a final amendment to the Transaction Statement to report the results of the transactions described below. At the Annual General and Special Meeting of the Company’s shareholders held on June 17, 2026, the requisite majority of the Company’s common shares, no par value per share (“Common Shares”) present in person or by proxy voted to authorize the changes in the Company’s share capital (the “Share Capital Amendment”), consisting of (a) the consolidation (the “Consolidation”) of the Common Shares on the basis of one post-Consolidation Common Share for every 150 pre-Consolidation Common Shares, and (b) the immediate subsequent split (the “Split”) of the Common Shares on the basis of 50 Common Shares for every one post-Consolidation Common Share. In connection with the Consolidation, the Share Capital Amendment is expected to become effective on July 3, 2026 (the “Effective Date”) for Common Shares held by shareholders as of such time, and the Common Shares are expected to begin trading on the Toronto Stock Exchange on a post-Share Capital Amendment basis within two business days of the Effective Date under the same trading symbol. Shareholders with positions representing fewer than 150 Common Shares as of the Effective Date will be entitled to receive cash consideration equal to the number of pre-Consolidation Common Shares held by such shareholder multiplied by US$1.60, in lieu of participating in the Split. Shareholders with positions representing 150 or more Common Shares as of the Effective Date will not receive cash consideration and will instead participate in the Split, resulting in their pre-Consolidation holdings being reduced by a factor of three (subject to rounding). Following the Effective Date, the Company plans to file a Form 15 with the U.S. Securities and Exchange Commission, which is anticipated to allow the Company to suspend its reporting obligations under the U.S. Securities Exchange Act of 1934, as amended.

SIGNATURES

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

Dated: June 22, 2026