Mr. Peter Puccetti reports

COSCIENS BIOPHARMA INC. COMPLETES SHARE CAPITAL AMENDMENT

Cosciens Biopharma Inc.'s previously announced consolidation of the common shares of the company on the basis of a ratio of one postconsolidation common share for every 150 preconsolidation common shares; and (ii) an immediate subsequent split of the common shares on the basis of 50 common shares for every one postconsolidation common share, became effective today.

Shareholders who held fewer than 150 common shares as of the close of business yesterday became entitled to a cash payment of $1.60 (U.S.) in exchange for their preconsolidation common shares. All other shareholders participated in the split and, as a result, will have their preconsolidation interest reduced by a factor of three (subject to rounding any postsplit fractional interests).

The common shares are expected to begin trading on a postshare capital amendment basis on the Toronto Stock Exchange within two business days of the effective date under the same trading symbol.

As previously announced, letters of transmittal were mailed to registered shareholders on or about May 26, 2026, providing instructions to surrender the certificates or DRS advices evidencing their common shares to the company's depositary and exchange agent, Computershare Investor Services Inc., for (i) in the case of holders of 150 or more common shares as of the effective date, replacement DRS advices representing the number of common shares such shareholder is entitled to as a result of the share capital amendment and (ii) in the case of holders of less than 150 common shares as of the effective date, the cash consideration. Copies of the letters of transmittal are available on the company's SEDAR+ profile.

The company is expected to proceed with filing a Form 15 with the U.S. Securities and Exchange Commission on July 6, 2026, which is anticipated to allow the company to suspend its reporting obligations under the U.S. Securities and Exchange Act of 1934, as amended.

About Cosciens Biopharma Inc.

Cosciens is a holding company, operating through its subsidiaries. Cosciens's principal operating subsidiary, Ceapro Inc., is focused on the development and commercialization of natural, plant-based active ingredients derived from oats and other renewable plant resources, using proprietary manufacturing and extraction technologies. Ceapro's primary active ingredient business activities relate to the development and commercialization of natural products for personal care, cosmetic, human and animal health industries using proprietary technology, natural, renewable resources and developing innovative products, technologies and delivery systems.

The company's common shares are listed on the TSX under the symbol CSCI and are listed and posted for trading on the OTCQB Venture Market under the symbol CSCIF.

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