AbCellera Receives Authorization from Health Canada to Initiate a Phase 1 Clinical Trial of ABCL575 ● ABCL575 is an Fc-silenced, half-life extended investigational antibody medicine that is being developed for the treatment of atopic dermatitis ● AbCellera anticipates starting the Phase 1 clinical trial for ABCL575 in Q3 2025 VANCOUVER, British Columbia– AbCellera (Nasdaq: ABCL) today announced it has received a No Objection Letter (NOL) from Health Canada authorizing its Clinical Trial Application (CTA) for ABCL575, an investigational antibody antagonist targeting OX40 ligand (OX40L) that is being developed for the treatment of moderate-to-severe atopic dermatitis (AD), with potential applications to other inflammatory and autoimmune conditions. The Phase 1 study is anticipated to begin in Q3 of 2025 and will evaluate the safety and pharmacokinetics of ABCL575 administered subcutaneously in healthy participants. About ABCL575 ABCL575 is an investigational monoclonal antibody for the treatment of moderate-to-severe atopic dermatitis (AD), with potential applications to other inflammatory and autoimmune conditions. ABCL575 binds OX40L to disrupt OX40/OX40L signaling, a regulator of inflammatory pathways in AD. It has been engineered with a modified Fc domain to support Fc-silencing and half-life extension. In preclinical studies, ABCL575 shows potent inhibition of T cell-mediated inflammatory pathways, favorable tolerability, and an in vivo half-life that is expected to support less frequent dosing than current clinical-stage molecules. A Phase 1 clinical trial is anticipated to begin in Q3 of 2025. About AbCellera Biologics Inc. AbCellera (Nasdaq: ABCL) discovers and develops antibody medicines for indications across therapeutic areas, including cancer, metabolic and endocrine conditions, and autoimmune disorders. AbCellera’s platform integrates technology, data science, infrastructure, and interdisciplinary teams to solve the most challenging antibody discovery problems. AbCellera is focused on advancing an internal pipeline of first-in-class and best-in-class programs and collaborating on innovative drug development programs with partners. For more information, please visit www.abcellera.com. AbCellera Forward-Looking Statements This press release contains forward-looking statements, including statements made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. The forward-looking statements are based on management’s current beliefs and assumptions and on information currently available to management. All statements contained in this release other than statements of historical fact are forward-looking statements, including statements regarding our ability to develop, commercialize, and achieve market acceptance of our current and

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