Cellectis : Corporate Presentation September 2020

COMMITMENT TO A CURE

cellectis.com

FORWARD-LOOKING STATEMENTS

This presentation contains "forward-looking" statements that are based on our management's current expectations and assumptions and on information currently available to management.

Forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements.

The risks and uncertainties include, but are not limited to the risk that the preliminary results from our product candidates will not continue or be repeated, the risk that our clinical trials will not be successful. The risk of not obtaining regulatory approval to commence clinical trials on additional UCART product candidates,

the risk that any one or more of our product candidates will not be successfully developed and commercialized.

Further information on the risk factors that may affect company business and financial performance, is included in our annual report on form 20-F and the financial report (including the management report) for the year ended December 31, 2019 and subsequent filings Cellectis makes with the Securities and Exchange Commission from time to time.

Except as required by law, we assume no obligation to update these forward-looking statements publicly, or to update the reasons actual results could differ materially from those anticipated in the forward-looking statements, even if new information becomes available in the future.

Cellectis proprietary information. Not to be copied, distributed or used without Cellectis' prior written consent.

P2

WRITING THE HISTORY OF ALLOGENEIC CAR T-CELLS

20 years	8 years	6 clinical trials
of expertise in	of experience in allogeneic	ongoing as of 2020;
gene editing	CAR-T manufacturing	3 Cellectis-sponsored
		3 partnered

INVENTORS / PIONEERS OF GENE EDITING & ALLOGENEIC CAR T-CELLS

In 2012 . .

Mission to develop allogeneic CAR T-cells begins

In 2015 . .

First-in-man compassionate use of an allogeneic CAR-T product candidate occurs

P3

ADVANTAGES OF ALLOGENEIC VS. AUTOLOGOUS CAR-T

Autologous process:		Manufacturing variability + several weeks before treatment is available

1.	2.	3.	4.
CANCER TREATMENT	CANCER	MANUFACTURING	INDIVIDUAL CAR-T
DECISION	PATIENT APHERESIS	OF A SINGLE	THERAPY
		PATIENT PRODUCT

Allogeneic process:

	Consistent manufacturing + quality		Immediate treatment

HEALTHY DONOR	SCALABLE	MASS PRODUCED	1.	2.
APHERESIS	MANUFACTURING	ALLOGENEIC CAR-T	CANCER TREATMENT	OFF-THE-SHELF
	OF 100+	THERAPIES	DECISION	CAR-T THERAPY
	DOSES/BATCH

• TIME SAVED
• COST EFFECTIVE
• MARKET ACCESS

P4

PARTNERSHIPS WITH INDUSTRY LEADERS

Up to $3.2B in potential milestone payments plus royalties

Exclusive license to 15 allogeneic

CAR T-Cell targets including

UCARTBCMA / ALLO-715

Exclusive license to CD19-directed allogeneic CAR T-Cellsincluding UCART19 / ALLO-501and

ALLO-501A1

Exclusive license agreement to use TALEN® technology to develop gene- edited TILs

Equity Investor

Up To $2.8B In Development & Sales Milestones + High Single-DigitRoyalties on Sales

Up To $410M In Development & Sales Milestones + Low Double-DigitRoyalties on Sales

Undisclosed Development & Sales Milestones + Royalties on Sales

6.56% ownership in Cellectis

As of June 30, 2020

P5

1UCART19/ALLO-501 and ALLO-501A are exclusively licensed to Servier and under a joint clinical development program between Servier and Allogene.

PIPELINE: INNOVATIVE CANCER THERAPIES FOR UNMET NEEDS

Disease

ACUTE MYELOID LEUKEMIA

ACUTE LYMPHOBLASTIC LEUKEMIA

MULTIPLE

MYELOMA

ACUTE LYMPHOBLASTIC LEUKEMIA

NON-HODGKIN'S LYMPHOMA1

MULTIPLE

MYELOMA

Product

UCART123

UCART22

UCARTCS1

UCART193

UCART193

UCARTBCMA4

Study	Preclinical	Phase 1	Phase 1	Pivotal Phase2
Dose Escalation	Dose Expansion
AMELI-01
BALLI-01
MELANI-01	ON CLINICAL	HOLD
CALM/PALL
ALPHA
UNIVERSAL				Proprietary development program
				Licensed development program

Cellectis and its partners are also working on a number of other preclinical targets

1 The ALPHA study targets Diffuse Large B-Cell Lymphoma (DLBCL) and Follicular Lymphoma (FL) indications, which are subtypes of HNL

2 We expect the pivotal phase to be the last clinical phase before commercializationP6 3 UCART19/ALLO-501 is exclusively licensed to Servier and under a joint clinical development program between Servier and Allogene

4 UCARTBCMA/ALLO-715 is exclusively licensed to Allogene

CLINICAL TRIAL: DESIGN OF PHASE 1 DOSE ESCALATION STUDIES

Primary Objectives:

Safety and Identification of Optimal Dose

Dose Escalation:

Optimal dose definition

Secondary Objectives:

Efficacy and Correlative Studies

DL1	DL2	DL3	DL4
2-4 patients	2-4 patients	2-4 patients	2-4 patients
DL: Dose Level			*for UCART123 only as
			required by FDA

P7

ALLO-501*: CELLECTIS LICENSED ALLOGENEIC CAR-T

PHASE 1 dose escalation in R/R Non-Hodgkin Lymphoma

Safety - Primary Objective

0%	Graft vs Host Disease
0%	ICANS (Immune Effector Cell-Associated
Neurotoxicity Syndrome)
5%	Grade 3	Cytokine Release Syndrome
9%	Grade 3	Infection
5%	Grade 3 Infusion Reaction

N=22 (safety)

N=19 (efficacy)

ALPHA Study

Efficacy - Secondary Objective

63% Overall Response Rate

37% Complete Response Rate

75% ORR in CAR-T naïve patients (N=16)

44% Complete Response Rate

Re-dosing one patient with ALLO-501 and ALLO-647 resulted in an ongoing CR

The ALPHA trial utilizes ALLO-647, Allogene's anti-CD52 monoclonal antibody as a part of its lymphodepletion regimen

Data Source: ASCO 2020 Conference Presentation	P8
The ALPHA study targets Diffuse Large B-Cell Lymphoma (DLBCL) and Follicular Lymphoma (FL) indications, which are subtypes of NHL.

• Cellectis granted to Servier an expanded exclusive worldwide license to develop and commercialize all next generation gene-edited allogeneic CAR T-cell products targeting CD19, including rights to ALLO-501.ALLO-501 is under a joint clinical development program between Servier and Allogene. Allogene is the sponsor of the ALLO-501 ALPHA study

UCART19: FIRST CELLECTIS LICENSED ALLOGENEIC CAR-T

PHASE 1 dose escalation in R/R ALL

Safety - Primary Objective

0%	Grade ≥2 skin Graft vs Host Disease
0%	Grade 3-4 neurotoxicity
14%	Grade 3-4 Cytokine Release Syndrome

N=21

		CALM PALL
Efficacy - Secondary Objective
82%	CR/CRi rate with optimal lymphodepletion
67%	overall CR/CRi rate
71%	of these patients were MRD-

Re-dosing with UCART19 resulted in cell expansion and MRD- status in 2/3 patients

Peak expansion observed mostly at Day 14

*Data Source: ASH 2018 Conference Presentation

Please note: this slide contains pooled data.P9 UCART19 is exclusively licensed to Servier and under a joint clinical development program between Servier and Allogene.

Lymphodepletion regimen consisting of fludarabine, cyclophosphamide and an anti-CD52 mAb.

UCART123 IN ACUTE MYELOID LEUKEMIA

AML Incidence Rates & Survival Data

19,940

27%

6%

Estimated new cases of AML in the US for 2020

5-year OS in adults

5-year OS in adults >55 years old

High CD123 expression on malignant cells

Limited CD123 expression on healthy cells

CD123 is expressed >90% on malignant cells

AML>90%in AML

Total bone marrow cells ~ 7% CD123 positive

Normal ~ 7%

Only ~ 1% expresses the antigen at high levels

Also expressed on BPDCN and Hodgkin's lymphoma

Cellectis Trial Recruitment Sites

P10

UCART22 IN ACUTE LYMPHOBLASTIC LEUKEMIA

ALL Incidence Rates & Survival Data

6,150		20%		<6
Estimated new cases of ALL in	5-year OS in adults		Months median disease-free survival
the US for 2020			in R/R pediatric patients

CD22 Expression in B-cells

Flow cytometric analysis of B-cell differentiation

CD19

CD22

A/B 1a 1b

2

3

Precursor-B-cell subpopulations

CD22 is expressed in >95% B-ALL cells

Treatment potential for CD19-negative patients

Pre-	CD22						Relapses following CD19-directed CAR T-cell
						therapy can show loss of CD19 antigen but
CAR
						persistent expression of CD22
					CD19
Post-	CD22						Anti-CD22 CAR T-cells can induce remissions in
						CD19 negative B-cells
CAR
					CD19

Cellectis Trial Recruitment Sites

P11

UCARTCS1 IN MULTIPLE MYELOMA

MM Incidence Rates & Survival Data

32,270

Estimated new cases of MM in the US for 2020

High expression on malignant cells

>95%

expression in MM cells

CS1 expression is high and uniform on MM cells

43-83		50%
Months is median OS for stages 2-3	5-year OS in adults

Treatment alternative to BCMA-targeted therapies

Many BCMA-targeted cell therapies show relapses

after 12-14 months of treatment

Elotuzumab, a CS1-targeting antibody, (in combination with lenalidomide and dexamethasone in R/R MM patients) shows:

5% CR rate and 45% partial remissions

Cellectis Trial Recruitment Sites

P12

UCARTs - ALLOGENEIC CAR T-CELLS THROUGH PRECISION GENE EDITING

R A T I O N A L

Engineering

via accurate insertion of best CAR

UCART

Universal Chimeric

Antigen Receptor T-cell

SAFE

Administration

Avoid GvHD via knock-out of T-Cell Receptor (TCR)

E F F E C T I V E

Persistence

via knock-out of CD52 or β2-microglobulin

TUMOR CELL

S M A R T

Action

CAR linked to suicide switch and other cell engineering features (e.g. PD-1 KO)

P13

TALEN® GENE EDITING - ADVANTAGES

TALEN®:

Driven by protein/DNA interactions to work on potential offsite cleavage

Releases DNA ends accessible to DNA repair mechanisms to perform gene insertions and corrections through homologous recombination and gene inactivation through non-homologousend joining

Over 20 years of building a strong patent portfolio with umbrella patents on gene editing

A) Gene insertion or Knock-In (KI)

Our nucleases act like DNA scissors to edit genes at precise target sites:

+

DNA sequence

• 16 RVDs

+

-

B) Gene correction

C) Gene inactivation or Knock-Out (KO)

>65% Knock-In	96.8% Knock-
Efficiency	Out Efficiency

Require homologous recombination

P14

UCART MANUFACTURING

Frozen	Thawed PBMCs	Lentivector	TALEN®-mediated gene
leukopaks		transduction	editing
1	2	3	4

Cell expansion	Purification	Fill & Finish	Frozen UCART products
5	6	7	8

8 years of experience in allogeneic CAR-T manufacturing

Validated gene editing technology for cell manufacturing

4 UCART product candidates manufactured so far

Full QC system in place

3 wholly controlled product candidates cleared for 3 clinical trials by the U.S. FDA

P15

IN-HOUSE MANUFACTURING

Raw materials	Clinical & Commercial UCART
		Product Candidates
	Paris, France

Raleigh, NC

14,000 sq ft. facility	82,000 sq ft. facility
Production of clinical	Operational "go-live"	Production of clinical &	Operational "go-live"
starting materials	targeted in 2020	commercial UCART	targeted in 2021
		product candidates	P16

THE CELLECTIS GROUP

~68.7%* ownership

NASDAQ: CLLS

EURONEXT GROWTH: ALCLS

~$282M** cash as of June 30, 2020 Expected to fund operations into 2022

Based in Paris, France, New York & Raleigh, USA Patient focused

Gene editing is the link

NASDAQ: CLXT $35M cash as of June 30, 2020 Cash Runway Extended into Fiscal Year 2022 Based in Minnesota, USA Consumer focused High value asset

* As of June 30, 2020	P17
** $317M of consolidated cash, cash equivalents, current assets and restricted cash (Cellectis + Calyxt)

MILESTONES

	Proprietary clinical programs				Partnered clinical programs
UCARTCS1: Phase 1 R/R MM - currently on		UCART19: Phase 1 in R/R ALL ongoing
clinical hold; first patient dosed in Q4
2019			UCART19 (ALLO-501/ALLO-501A):Phase 1
UCART22: Phase 1 in R/R ALL ongoing; first		in R/R NHL ongoing, data presented at ASCO
	2020; first patient dosed in H1 2019
patient dosed in Q4 2019		UCARTBCMA (ALLO-715):Phase 1 in R/R
UCART123: Phase 1 for R/R AML ongoing;		MM ongoing, first patient dosed in H2 2019
New IND granted by FDA in Q3 2019

Manufacturing

Ongoing construction of 2 in-house manufacturing plants:

Facility in Paris, France for raw material supply

Facility in Raleigh, North Carolina for GMP, commercial scale UCART manufacturing

EXPECTED MILESTONES IN 2020

	Clinical programs				Manufacturing
Provide interim clinical data on completed dose cohorts for		Go-live with Paris facility
proprietary and partnered programs at relevant scientific		Construction complete for Raleigh facility
conferences

UCART19/ALLO-501 is exclusively licensed to Servier and under a joint clinical development program between Servier and Allogene.

P18

UCARTBCMA is exclusively licensed to Allogene

THANK YOU

Reach us at: [e-mail]

Cellectis Paris	Cellectis New York	Cellectis Raleigh
8, rue de la Croix Jarry	430 East 29th Street	2500 Sumner Boulevard
75013 Paris - France	10016 New York, NY - USA	27616 Raleigh, NC - USA