Slide 1: Corporate Update
CORPORATE UPDATE September 14th , 2026 1
Slide 2: Forward Looking Statements
Forward Looking Statements This press release contains “forward-looking” statements within the meaning of applicable securities laws, including the Private Securities Litigation Reform Act of 1995. Forward-looking statements may be identified by words such as “design”, “expect”, “initiate”, “into”,
Slide 3: Agenda and Speakers
Agenda and Speakers Speakers Welcome Cellectis, A Gene Editing Company André Choulika, PhD In vivo Gene Editing Chief Executive Officer Strategic Transformation Q&A Adrian Kilcoyne, MD, MPH,MBA Chief Medical Officer 3
Slide 4: Gene Editing
Gene Editing
Slide 5: Cellectis is a Gene Editing Company
Cellectis is a Gene Editing Company Cellectis since its inception over 25 years ago is a pioneer in Gene Editing Gene Editing intervenes in cells at genome level to change gene expression by: Silencing Activating Repairing targeted gene(s) Gene Editing has transformed science in numerous ways and ma
Slide 6: Gene Editing in Medicine
Gene Editing in Medicine Genetics drive disease: Cancer, diabetes, obesity, neurological disorders, immunity, longevity… all diseases are rooted in genetics: polymorphisms and aberrant gene expression. The basic logic of gene editing: fix the gene, fix the disease. EX VIVO Collect cells Cellectis ma
Slide 7: in vivo Gene Editing
in vivo Gene Editing
Slide 8: How does In Vivo Gene Editing Work
How does In Vivo Gene Editing work In vivo delivered is made by intravenous injection (IV) product liver cells A single IV injection for a long-lasting effect 8
Slide 9: What is The in vivo Gene Editing Product?
What is The in vivo Gene Editing Product? Product: AAAAAA 3′ mRNA coding for a gene editor AAAAAA 3′ in a lipid nanoparticle (LNP) A One-Time Treatment With a Long-Lasting Effect 9
Slide 10: Two Promising Preclinical In Vivo Assets
Two Promising Preclinical In Vivo Assets Decision to advance 2 preclinical candidate products in dyslipidemia: .HEAL-101 (mRNA+LNP) .HEAL-201 (mRNA+LNP) Targeting APOC3 in severe Targeting PCSK9 in severe hypertriglyceridemia (sHTG) hypercholesterolemia ✓ Well validated targets ✓ Single IV injection
Slide 11: .HEAL-101
e -HEAL-101 F GENE SURGERY
Slide 12: Severe Hypertriglyceridemia (sHTG): A Major Unmet Medical Need
Severe Hypertriglyceridemia (sHTG): A Major Unmet Medical Need High Clinical Burden .HEAL-101 Target Patient Population High risk of acute pancreatitis High Risk sHTG (TGs ≥ 880 Associated with cardiovascular mg/dL or ≥ 500 mg/dL With Prior disease AP History) Poor quality of life and limited Total:
Slide 13: .HEAL-101 Indication: Severe Hypertriglyceridemia
.HEAL-101 Indication: Severe Hypertriglyceridemia (sHTG) with high risk of acute pancreatitis Target: APOC3 gene is well-validated with ASO and RNAi Tech: TALE-Base Editor disables the APOC3 gene Goal: One-time treatment for durable lowering of triglycerides to reduce risk of acute pancreatitis Stat
Slide 14: .HEAL-101: TALE-Base Editor Targeting APOC3
.HEAL-101: TALE-Base Editor Targeting APOC3 .HEAL-101 is a base editor C to T conversion It modifies one base in DNA .HEAL-101 No DNA break offering potential of improved safety profile 14
Slide 15: .HEAL-101: Disable APOC3 Expression
.HEAL-101: Disable APOC3 Expression APOC3 gene expression .HEAL-101 editing location A stop codon is generated APOC3 protein is disabled 15
Slide 16: .HEAL-101 Elicits Efficient and Specific Editing of APOC3 Gene
.HEAL-101 Elicits Efficient and Specific Editing of APOC3 Gene .HEAL-101 mRNA is introduced in hepatic cell lines Efficient on-site modification with No modification no DNA alteration of top putative off-sites 80 80 Edited Editing 70 60 Mock Indels base edting (%) Frequency of 60 50 Frequency of 40
Slide 17: .HEAL-101 Stops APOC3 Expression In Vitro
.HEAL-101 Stops APOC3 Expression In Vitro .HEAL-101 Mock 100 80 Stop codon (%) Frequency of 60 Frequency of APOC3 editing 40 20 0 0 of APOC3 secretion (%) Normalized decrease 20 Quantification of APOC3 secretion 40 60 80 100 Mock .HEAL-101 17
Slide 18: .HEAL-101 Decreases Triglycerides in Humanized Mice
.HEAL-101 Decreases Triglycerides in Humanized Mice 100 20 20 Before/After treatment (%) Change from baseline (%) 0 0 Frequency of editing (%) 80 -20 -20 .HEAL-101 Change 60 -40 -40 40 -60 -60 20 -80 -80 0 -100 -100 Control .HEAL-101 Base editing Indels Control .HEAL 101 Precise Decrease of Drop of
Slide 19: .HEAL-101 Induces 76% Decrease of Triglycerides in Affected Mice
.HEAL-101 Induces 76% Decrease of Triglycerides in Affected Mice APOC3 Triglycerides 100 100 Change from baseline (%) Change from baseline (%) 50 50 20 20 .HEAL-101 0 0 -20 -20 -40 70% -40 76% -60 decrease -60 decrease -80 -80 -100 -100 Control .HEAL-101 Control .HEAL-101 19
Slide 20: .HEAL-201
e -HEAL-201 F GENE SURGERY
Slide 21: Hypercholesterolemia: A Major Unmet Medical Need
Hypercholesterolemia: A Major Unmet Medical Need High Clinical Burden .HEAL-201 Target Patient Population • Leading driver of atherosclerotic • Younger high risk patients cardiovascular disease • Premature Cardiovascular • Lowering LDL-C reduces risk of disease cardiovascular event (CVE) • Persisten
Slide 22: .HEAL-201 Indication: Severe Hypercholesterolemia
.HEAL-201 Indication: Severe Hypercholesterolemia Target: PCSK9 gene is a well validated target Tech: TALE-Modulator silences the PCSK9 gene Goal: One-time treatment for durable lowering of LDL-C to reduce CVE risk Status: Promising preclinical data supporting transition to clinic CVE: cardiovascula
Slide 23: .HEAL-201: TALE-Epigenetic Modulator Targeting PCSK9
.HEAL-201: TALE-Epigenetic Modulator Targeting PCSK9 .HEAL-201 is an Epigenetic modulator PCSK9 is active .HEAL-201 binds target Epigenetically modulates the PCSK9 gene without altering PCSK9 is silenced the DNA sequence No DNA Sequence Change 23
Slide 24: .HEAL-201 Promotes Efficient and Specific Knockdown of PCSK9
.HEAL-201 Promotes Efficient and Specific Knockdown of PCSK9 Epigenetic change in the DNA without sequence modification Efficient PCSK9 mRNA transcription reduction 1.0 0.8 Fold Change 0.6 0.4 0.2 0.0 Control .HEAL-201 PCSK9 transcription is shut down 24
Slide 25: .HEAL-201 Promotes Efficient and Specific Knockdown of PCSK9
.HEAL-201 Promotes Efficient and Specific Knockdown of PCSK9 Epigenetic change in the DNA without sequence modification Efficient PCSK9 protein reduction 100 90 Normalized PCSK9 80 70 secretion (%) 60 Mock 50 40 .HEAL-201 30 20 10 0 0 7 14 21 28 35 42 49 Day # (Post-Transfection) PCSK9 protein is tu
Slide 26: .HEAL-201 Promotes Efficient and Specific Knockdown of PCSK9
.HEAL-201 Promotes Efficient and Specific Knockdown of PCSK9 Transcriptome post .HEAL-201 treatment shows a precise modification PCSK9 Magnitude of change vs baseline Other genes Downregulated →Up-regulated .HEAL-201: high specificity on PCSK9 only 26
Slide 27: .HEAL-201 Epigenetic Modification is Stable Over Time
.HEAL-201 Epigenetic Modification is Stable Over Time 20 .HEAL-201 treated with respect to W-1 (%) 0 Decrease of PCSK9 .HEAL-201 -20 -40 -60 -80 -100 -1 0 1 2 3 4 5 Time (week) .HEAL-201 promotes rapid and durable decrease of PCSK9 27
Slide 28: Clinical Development Plan
Clinical Development Plan
Slide 29: .HEAL-101 Clinical Development Plan
.HEAL-101 Clinical Development Plan 1 Phase 1 Study 2 Phase 1b/2 Study • Patient population: severe hypertriglyceridemia (sHTG) • Expand to global populations • First-in-Human for safety and tolerability • Dose optimization and regimen exploration • Establish dose efficacy in triglyceride reduction
Slide 30: .HEAL-201 Clinical Development Plan
.HEAL-201 Clinical Development Plan 1 Phase 1 Study 2 Phase 1b/2 Study • Younger high risk patients • Patient Population: Severe hypercholesterolemia ≥190 mg/dL • Severe genetic hypercholesterolemia — • First-in-Human for safety and tolerability LDL-C ≥190 mg/dL • Establish dose efficacy in LDL-C re
Slide 31: Advancing Toward First-In-Human Proof of Concept
Advancing Toward First-In-Human Proof of Concept Getting to first human data IND/CTA enabling activities • Plan to start an IIT in China • FDA / EMA preparation initiated • GMP manufacturing starting • Manufacturing scope broadened toward • Phase 1 designed to be optimized for rapid global supply do
Slide 32: A Differentiated Gene Editing Platform
A Differentiated Gene Editing Platform
Slide 33: Cellectis' Core Competencies
Cellectis’ Core Competencies Nuclease Base Editor Epigenetic Transcription ✓ ✓ ✓ ✓ .HEAL-101 .HEAL-201 ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ 33
Slide 34: Cellectis' Unique Advantages
Cellectis’ Unique Advantages Broad Gene Editing Strong Differentiation Unique Advantages Toolbox • TALE editors • Nuclease editing • Binding does not nick DNA • Base editing • Any Gene Editing modality • Precision to the base pair • Epigenetic editing • Hybrid tools combinations • 32 base pairs reco
Slide 35: Cellectis' Strategic Decision to Pivot to in vivo Gene Editing
Cellectis’ Strategic Decision to Pivot to in vivo Gene Editing
Slide 36: Changes in the Heme-Onc Landscape in 2026
Changes in the Heme-Onc Landscape in 2026 B-ALL: • Frontline Blinatumumab consolidation reduces relapses to 15-25% (vs 45-55% before its introduction), substantially reducing 3 rd line+ B-ALL patients • New 2nd and 3rd line+ pipeline drugs with novel bispecifics and ADCs • Focus shifts from salvage
Slide 37: Cellectis Pivot
Cellectis Pivot Cellectis Today Cellectis Tomorrow EX VIVO CELL THERAPY EX VIVO CELL THERAPY Lasme-cel Eti-cel Cell therapy Exiting internal programs in Pivotal Phase 1 Partnered Continuing existing collaborations Phase 2 Completed programs IN VIVO GENE EDITING IN VIVO GENE EDITING Promising Preclin
Slide 38: Cellectis Targeted Roadmap
Cellectis Targeted Roadmap Advancing 2 Lead Assets FIH Data disclosure .HEAL-101 targeting APOC3 in severe hypertriglyceridemia H1-27 H2-27 .HEAL-201 targeting PCSK9 in severe hypercholesterolemia H2-27 H1-28 Continuing Existing Partnerships Targeting Cash Runway into H2 2028* Exiting internal cell
Slide 39: HEAL Gene Surgery
HEAL GENE SURGERY By EDITING LIFE 39
Slide 40: Questions & Discussion
Questions & Discussion André Choulika, PhD David Sourdive, PhD Chief Executive Officer Executive Vice President CMC and Manufacturing Arthur Stril Adrian Kilcoyne, MD, MPH,MBA Chief Business Officer & Chief Medical Officer Chief Financial Officer 40