COSCIENS Biopharma Inc. — Proxy Solicitation & Information Statement 2021

Mar 5, 2021

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March 5, 2021

1500 Robert-Bourassa Blvd., 7th Floor Montreal QC, H3A 3S8 www.computershare.com

To: All Canadian Securities Regulatory Authorities

Subject: Aeterna Zentaris Inc.

Dear Sir/Madam:

We advise of the following with respect to the upcoming Meeting of Security Holders for the subject Issuer:

Meeting Type : General and Special Meeting Record Date for Notice of Meeting : March 30, 2021 Record Date for Voting (if applicable) : March 30, 2021 Beneficial Ownership Determination Date : March 30, 2021 Meeting Date : May 5, 2021 Meeting Location (if available) : Virtual Meeting Issuer sending proxy related materials directly to NOBO: No Issuer paying for delivery to OBO: Yes

Notice and Access (NAA) Requirements:

NAA for Beneficial Holders No NAA for Registered Holders No

Voting Security Details:

Description CUSIP Number ISIN COMMON SHARES 007975402 CA0079754028

Sincerely,

Computershare

Agent for Aeterna Zentaris Inc.