Dr. Klaus Paulini reports

AETERNA ZENTARIS PROVIDES BUSINESS UPDATE AND OUTLINES KEY UPCOMING MILESTONES

Aeterna Zentaris Inc. has provided a business update and has outlined upcoming key milestones.

"We have made significant development progress since we initiated six pre-clinical development programs in 2021," said Dr. Klaus Paulini, Chief Executive Officer of Aeterna. "We have established a growing body of data towards our pre-defined go/no-go decision points with the goal of enabling us to identify and select from those programs the most compelling opportunities that warrant continued development. We believe that we have built the foundation for continued momentum and are very encouraged with the disciplined progress we have made thus far."

Diagnostics Development and Commercialization Update Macimorelin Diagnostic: Approved and commercialized as test for adult growth hormone deficiency and in clinical phase 3 development for childhood-onset growth hormone deficiency ("CGHD") testing

Aeterna is currently conducting its pivotal Phase 3 safety and efficacy study AEZS-130-P02 (the "DETECT-trial") evaluating macimorelin for the diagnosis of Childhood Onset Growth Hormone Deficiency ("CGHD"). Most clinical sites in the U.S. as well as European countries are open for patient recruitment.

Recent Highlights

Phase 3 S tudy: Bolstered enrollment expected by the replacement of inactive countries/sites and engagement of an additional Clinical Research Organization (CRO). Currently four new countries (Armenia, Slovakia, Greece, and Turkey), have ongoing DETECT clinical trial application activities.

Macimorelin C ommercialization: Having announced that Aeterna Zentaris will regain full rights to Macrilen(TM) for the U.S. and Canada from Novo Nordisk in May 2023, the Company is progressing its efforts to seek an alternate development and commercialization partner for Macrilen(TM) in those countries for continued commercialization of Macrilen(TM) in adult growth hormone deficiency ("AGHD") and development and commercialization of Macrilen(TM) in CGHD.

Achieved regulatory approval for Macrilen(TM) as AGHD diagnostic product in Israel.

Next Steps and Expectations

Achieve approvals to conduct the DETECT trial in the new countries in the first half of 2023.

Complete DETECT enrollment by the end of 2023.

Continue efforts to secure a U.S. and Canadian development and commercialization partner for Macrilen(TM) in AGHD and CGHD.

Achieve regulatory approval for Macrilen(TM) as AGHD-diagnostic in South Korea, Turkey and some non-EU Balkan countries.

Decision to Discontinue O ur Early - Stage Vaccine Development Pipeline

Orally active, live-attenuated bacterial vaccine platform with potential application against coronavirus, including COVID-19 (SARS-CoV-2) and Chlamydia

The Company worked on evaluating administration routes, dosing and immunization scheme, and conducted in-vivo immunology experiments with candidate strains expressing various antigens in relevant mice models. To date, the Company has not been able to select a clinical development candidate for a COVID-19 vaccine.

Also, COVID-19 vaccine landscape has continued to evolve profoundly in the past two years. There are highly effective vaccines available, an increasing number of therapeutic options are meanwhile approved or in later stage development and less lethal virus variants are spreading, all of which increase the financial risk associated with any early stage COVID-19 vaccine program. In order to ensure we are prudent with the use of resources, given the early stage of the Company's vaccine development programs and the changes in the global situation, Aeterna has decided that it will not pursue further development of the vaccine platform for either COVID-19 or Chlamydia (which was based on the same vaccine platform as used in the Company's COVID-19 program). As a result, the Company has also elected to terminate its existing license agreements with the University of Wuerzburg for that vaccine platform technology.

Therapeutics Development Pipeline Update Autoimmunity Modifying ("AIM") Biologicals :

Targeted, highly specific autoimmunity modifying therapeutics for the p otential treatment of neuromyelitis optica spectrum disorder ("NMOSD") and Parkinson's disease ("PD")

Recent Highlights

Demonstrated positive pre-clinical proof-of-concept in NMOSD and PD.

NMOSD selected as lead development program.

Entered into an R&D agreement with Massachusetts General Hospital (MGH) in Boston and Dr. Michael Levy, a worldwide leading NMOSD expert.

Further optimization of candidates for potential use in clinical development.

Initiated ex-vivo efficacy testing to confirm the AIM Biologicals mechanism of action and efficacy in human blood samples from both NMOSD and PD patients.

Next Steps and Expectations

Following the completion of the pre-clinical studies, Aeterna plans to compile a comprehensive pre-clinical data package for scientific advice meetings with regulatory authorities, expected to take place in the third quarter of 2023.

Delayed Clearance Parathyroid Hormone ("DC-PTH" , AEZS-150 ) Fusion Polypeptides: Potential treatment for chronic hypoparathyroidism

Recent Highlights

Successful verification and reproduction of previous in-vivo data from University of Sheffield, in a rat model of hypoparathyroidism, in the fourth quarter of 2022.

Ongoing development of the manufacturing process for AEZS-150 with the Company's contract development and manufacturing organization, progressing toward establishment of a master cell bank for a cell line expressing AEZS-150 and a process suitable for larger scale GMP manufacturing.

Next Steps and Expectations

Continue efforts to establish master cell bank for a cell line expressing AEZS-150 to be used to conduct further pre-clinical efficacy and safety tests.

Meet with regulatory authorities to determine the development path forward; Company expects meeting in mid-2023 and an abbreviated safety and toxicology program as the active principle ([1-34)-PTH fragment) is already approved and in use.

Macimorelin Therapeutic ( AEZS-130 ) : Ghrelin agonist in development for the treatment of

ALS (Lou Gehrig's disease)

Recent Highlights

Substantial progress in the development of a suitable, alternative formulation for use in ALS.

Ongoing evaluation of AEZS-130 in transgenic mouse ALS models to demonstrate the therapeutic potential of macimorelin in this indication.

Next Steps

Proof-of-concept results from ongoing pre-clinical studies expected in the first quarter of 2023.

Following potential achievement of proof-of-concept, the Company will seek to have a scientific advice meeting with regulatory authorities to discuss program development next steps.

Toxicology and safety studies to support treatment over prolonged periods are ongoing and based on the substantial body of pre-clinical and clinical data already available from the successful development of macimorelin (Macrilen(TM)) as a diagnostic in AGHD.

Strategic Conclusion

"Our disciplined development strategy ensures that we establish progress in our projects within a defined timeframe, in order to optimize the Company's capital and human resources," said Giuliano La Fratta, Chief Financial Officer, Aeterna. "We continue to drive progress across a number of our programs and remain focused on advancing those programs to their next phase of development if we determine that the data and financial risk/reward of doing so is justified. The strategic decision to streamline our pipeline, by discontinuing our vaccine development, provides the Company with the ability to meet its currently anticipated cash needs into 2025. Revenues that may be achieved if we out-license any of those development programs are not considered in our budget and thus provides further upside potential."

About Aeterna Zentaris Inc.

Aeterna Zentaris is a specialty biopharmaceutical company developing and commercializing a diversified portfolio of pharmaceutical and diagnostic products focused on areas of significant unmet medical need. The Company's lead product, macimorelin (Macrilen(TM); Ghryvelin(TM)), is the first and only U.S. FDA and European Commission approved oral test indicated for the diagnosis of adult growth hormone deficiency (AGHD). The Company is leveraging the clinical success and compelling safety profile of macimorelin to develop it for the diagnosis of childhood-onset growth hormone deficiency (CGHD), an area of significant unmet need, in collaboration with Novo Nordisk.

Aeterna Zentaris is dedicated to the development of therapeutic assets and has recently taken steps to establish a growing pre-clinical pipeline to potentially address unmet medical needs across a number of indications, including neuromyelitis optica spectrum disorder (NMOSD), Parkinson's disease (PD), hypoparathyroidism and amyotrophic lateral sclerosis (ALS; Lou Gehrig's disease).

We seek Safe Harbor.