CORPORATE PRESENTATION

MAY 2020

The statements made in this presentation may include forward-looking statements regarding thefuture operations of ERYTECH Pharma S.A., including estimates of target market opportunity,timing of planned clinical trials and results from those trials, regulatory strategy and timing ofplanned regulatory submissions, manufacturing capabilities and strategy for expansion of theERYCAPS platform. Although we believe that the expectations contained in this presentation arereasonable, these forward-looking statements are only estimates based upon the informationavailable to ERYTECH Pharma S.A. as of the date of this presentation. The company'sexpectations regarding the effects of COVID-19 on the Company's trials and development may beincorrect. Except as required by law, we expressly disclaim any responsibility to publicly update orrevise our forward-looking statements, whether as a result of new information, future events orotherwise. Thus, the forward-looking statements herein involve known and unknown risks anduncertainties and other important factors such that actual future operations, opportunities orfinancial performance may differ materially from these forward-looking statements. Undue relianceshould not be placed on forward-looking statements, which speak only as of the date hereof. Allforward-looking statements contained herein are qualified in their entirety by the foregoingcautionary statement.

Forward Looking Statements

33

Leader in Red Blood Cell-based Cancer Therapeutics

Months

Phase 2b in 2L Pancreatic Cancer

OVERALL SURVIVAL (ITT)

Reproducible encapsulation of therapeutic compounds in red

blood cells

Focus on oncology, targeting cancer cells’ altered amino acid

metabolism through encapsulated asparaginase

Lead product candidate eryaspase, first asparaginase to show

efficacy in solid tumors; strongest survival benefit observed in any

2L pancreatic cancer study to date

Phase 3 trial in 2L pancreatic cancer ongoing in EU and US;

Phase 2 in 1L TNBC and Phase 2 IST in 2L ALL ongoing

Industrialized production: own cGMP production facilities in the

United States and Europe

Listed on Nasdaq and Euronext; cash runway into Q1 2021

reduction in

risk of death

(HR, 0.60;

P=0.008)

40%

ALL: Acute Lymphoblastic Leukemia; TNBC: Triple-Negative Breast Cancer

Hammel et al., European Journal of Cancer, 2019

4

Late Stage Clinical Pipeline and Preclinical Programs

4

Mode of actionProduct Candidate

or ProgramIndication Discovery Pre-clinical Phase 1 Phase 2

Phase 3/

Pivotal

Next Anticipated

Milestone

Cancer metabolism

Tumor starvation

eryaspase/GRASPA®

(asparaginase)

Pancreatic Cancer

2L

Interim: YE 2020

Final: 2H 2021

Triple Negative

Breast Cancer 1L Final: 2021

Acute Lymphoblastic

Leukemia 2L

Interim: 1H 2020

Final: 2H 2020

Pancreatic cancer

1LLaunch: 2H 2020

erymethionase

(methionine-γ-lyase)Solid tumors

Immune

modulation

Immune-oncology

Tolerance inductionTBD*

Enzyme

replacement

Therapeutic

enzymesMetabolic diseases

1L First Line; 2L Second Line; IST Investigator Sponsored Trial; NOPHO : Nordic Organization of Pediatric Hematology and Oncology

* To be determined by SQZ Biotech

TRYbeCA-1

IST

TRYbeCA-2

NOPHO IST

5

Red Blood Cells, Ideal Carriers for Amino Acid Lowering Agents

Well known

biocompatibility

Routine allogeneic use

Protective membrane

Reduced toxicity

Prolonged activity

Readily available at blood

banks

Established sourcing

Most abundant cell in

human body

Extensive biodistribution

Permeable membrane

Potential to load with drugs

Plasma metabolites can pass

Long circulating life

Prolonged activity

5

6

ERYCAPS, an Innovative Technology Platform

Reproducibly encapsulating drug substances inside allogeneic red blood

cells using proprietary hypotonic loading technology

Reproducible

proprietary ‘osmotic fragility’ process enables

reproducible loading

Fast

industrialized process can deliver tailored therapy

within 24 hours

Broad range

peptides, RNA, proteins, antibodies, …

Strong IP

265 granted patents in 15 patent families

Controlled

Hypotonic Loading

Hypertonic

Resealing

Drug substance

Pores

6

7

Fully-owned GMP

production capacity in EU

and the US

Established partnerships

with blood banks in EU and

the US

More than a decade

experience in manufacturing

and supply chain management

Validated supply &

manufacturing model – 3000+

batches, 500+ patients

treated,10+ countries

Industrialized and Scalable ProcessP

RE

SC

RIP

TIO

N

Sourcing of

compatible RBC

PREPARATION

2

SOURCING

1

BATCH RELEASE

4

ENCAPSULATION

3

SHIPPING

5

Identification of key

parameters

ERYCAPS automated

Manufacturing

(3-5 hours)

QC Control

Release by QPShipping

Patient

Preparation2

Sourcing1

Batch releaseEncapsulation3 4

Shipping5

Possible in 24h

7

8

Targeting Cancer Cells Amino Acid Metabolism, an Emerging Field

Many cancers exhibit increased demand

for specific amino acids, becoming

dependent on exogenous supply or de

novo synthesis of these amino acids1-3 Depleting select amino

acids in blood (e.g.

asparaginase)

Blocking uptake by

blocking transporters

(e.g., LAT 1-4)

Inhibiting biosynthetic or

catabolic enzymes (e.g.

arginase inhibitor)

Amino acids

1. Lukey et al., Drug Discovery Today, 2017

2. Pavlova & Thompson, Cell Metabolism, 2016

3. Luengo et al., Cell Chemical Biology, 2017 8

9

CURRENT

USE

• Cornerstone treatment in Phi-neg pediatric acute lymphoblastic leukemia (ALL)

• Four forms of L-asparaginase products currently marketed in ALL; worldwide sales

est. $400M in 2018

• E-coli derived: Native asparaginase: e.g., Kidrolase (Kyowa Hakko)

Recombinant asparaginase: Spectrila (medac)

Pegylated asparaginase: Oncaspar (Servier)

• Erwinia derived: Erwinaze (Jazz Pharmaceuticals)

MODE OF

ACTION

Asparaginase breaks down circulating asparagine (and glutamine), and deprives

tumor cells of amino acids essential for their growth

• Important side effects (e.g., allergies, coagulation disorders, pancreatic and hepatic

toxicities) limit therapeutic window to essentially pediatric ALL

• Beyond ALL, some use in AML and lymphoma; no known use in solid tumors

Asparaginase, First Amino Acid Targeting Anticancer Drug1

1. Lukey et al., Drug Discovery Today, 2017

Mode of action

Current use

Limitations

9

10

Active transporters in membrane

of red cell pump circulating

asparagine and glutamine into

the red cell…

Y

Asparagine and glutamine

Asparaginase

Antibody

…where the encapsulated

L-asparaginase hydrolyzes the

asparagine and glutamine

Eryaspase (GRASPA®️), Enabling Broader Use of Asparaginase

A novel circulating ‘bioreactor’ to degrade asparagine (and glutamine)

Prolonged activity

Reduced toxicity

Potential to provide

asparaginase to patients

that are unable to

tolerate non-

encapsulated products

Degradation products

10

11

• ERYTECH started development in fragile ALL patients, confirming the concept of prolonged activity and

reduced toxicity in different clinical trials, including a Phase 2/3 trial in Relapsed/Refractory ALL:

Positive Results in ALL Confirmed Proof of Concept

Key results of Phase 2/3 trial in R/R ALL Eryaspase (N=26) L-ASP (N=28)

% of patients with ≥ 1 hypersensitivity reaction during induction** 0% 46%

Mean duration of asparaginase activity above 100 U/L during induction (days)** 18.9 8.5

Complete Remission rate (CR)* 65% 36%

Overall Survival (OS) HR = 0.72

** Statistically significant (p<0.001) * Statistically significant (p<0.05). Presented at ASH 2014

• The favorable safety profile observed in these trials enabled ERYTECH to pursue the development of

bringing eryaspase to the much larger unmet medical need of solid tumors

11

12

Pancreatic Cancer, Large Unmet Medical Need

• Pancreatic cancer is one of the leading

causes of cancer death in the world, with an

increasing incidence1,2

• In 2018, approximately 185,000 people were

newly diagnosed with pancreatic cancer in

Europe and the United States1

• Overall prognosis for pancreatic cancer is

poor, with a 5-year survival rate of <10%2

• Approximately 50% of pancreatic cancer

patients are eligible for second line treatment3

• Chemotherapy remains main treatment

option; limited progress in development of

new treatment options

203020202010

Pro

jecte

d c

an

ce

r d

ea

ths in

th

e U

S (

10

00

’s)

0

20

40

60

160

Year

Lung and bronchus

Pancreas

Liver

Leukaemia

80

140

Colon and rectum

Breast

Prostate

Bladder

1. WHO Cancer Today, Globocan 2018; 2. Rawla et al. WJO 2019 ; 3. Hua et al. Onco Targets Ther, 2018 12

13

• Pancreatic cancer (PAC) is characterized by extensive reprogramming of cellular metabolism leading to

increased asparagine and glutamine requirements. Deprivation of glutamine and asparagine results in loss of

cancer cell viability1

• In vitro studies demonstrated promising anti-cancer effects for asparaginase against human pancreatic tumor

cell lines2-3

• Attempts at evaluating asparaginase in solid tumor indications in the clinic have been unsuccessful due to

toxicity4-7

• In a Phase 1 trial in metastatic pancreatic cancer, eryaspase demonstrated an acceptable safety profile8-9

• The tolerability of eryaspase and the potential role of metabolic dysregulation in this disease provided

rationale for further clinical evaluation

Altered Metabolic Pathways in PAC, a Role for Asparaginase?

1. Kawanda Int J Clin Oncol 2017; 2. Cui, Cancer Res 2007; 3. Dufour, Pancreas 2012;

4. Lessner Cancer Treat Rep 1980; 5. Hays Molec Clin Oncol 2013; 6. Agrawal Cancer 2003;

7. Borad Cancer Investigation 2015; 8. Bachet Pancreas 2015; 9. ClinicalTrials.gov: NCT01523808 13

14

Phase 2b Trial in 2L Pancreatic Cancer Launched in 2014

Co-primary endpoints

Ra

nd

om

ize

2 to

1 03

option

Patients (N=141)

PFS and OS in ASNS 0/1

subpopulation

Key secondary endpoints

• PFS and OS (all comers)

• Objective response rate

• Disease control rate

• Safety and tolerability

• Quality of life

Eryaspase +

chemotherapy

(gemcitabine or

mFOLFOX)

Chemotherapy alone

(gemcitabine or

mFOLFOX)

• ≥18 years

• Stage III or IV

• One prior systemic

chemotherapy in

advanced setting

• Measurable disease

• ECOG PS 0 or 1

Reference: ClinicalTrials.gov: NCT02195180

ECOG: Eastern Cooperative Oncology Group, PS: performance status, FOLFOX: 5FU, leucovorin and oxaliplatin; GERCOR: Multidisciplinary Group in Oncology

ASNS 0/1 subpopulation: patients with no/low asparagine synthetase expressing tumors

Stratified by chemotherapy

14

Trial in collaboration with the GERCOR in 16 clinical sites in France

15

40%reduction in risk of death (HR 0.60; P=0.008)

I T T P O P U L A T I O N

Eryaspase +

chemotherapy

(n=95)

Chemotherapy

(n=46)

Events, n (%) 82 (86.3) 42 (91.3)

Median OS,

months

(95% CI)

6.0

(4.8–6.6)

4.4

(3.0–5.0)

P value 0.008

0

10

20

30

40

50

60

70

80

90

100

Surv

ival pro

babili

ty (

%)

Months0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36

No. at risk

E +CT 95 83 67 45 29 24 15 11 8 8 4 4 4 1 1 1 1 0

CT 46 35 22 15 8 6 3 0

For reference: Onyvide Phase 3: HR 0.67

I T T P O P U L A T I O N

Eryaspase Phase 2b Trial

1. Hammel et al., European Journal of Cancer, 2019;

Events n (%) 79 (83%) 40 (87%)

OS HR (95% CI)

P-value

0.60 (0.40, 0.88)

0.008

Median OS (mo) 6.0 4.4

OS rate at 1yr

OS rate at 18m

15.8%

8.4%

6.5%

0%

Clear Overall Survival (OS) Benefit1

15

HR, Hazard Ratio; OS, Overall Survival

16

All patients (E+CT n=95, CT n=46)

ASNS 0/1+ (E+CT n=66, CT n=32)

ASNS 2+/3+ (E+CT n=29, CT n=14)

Male (E+CT n=53, CT n=30)

Female (E+CT n=42, CT n=16)

<6 months (E+CT n=31, CT n=14)

≥6 months (E+CT n=64, CT n=32)

0 (E+CT n=29, CT n=11)

1 (E+CT n=63, CT n=32)

<3 (E+CT n=90, CT n=44)

Normal (E+CT n=19, CT n=6)

Elevated (E+CT n=66, CT n=31)

mFOLFOX6 (E+CT n=11, CT n=5)

Gemcitabine (E+CT n=84, CT n=41)

OR+SD (E+CT n=63, CT n=30)

PD (E+CT n=30, CT n=16)

0.60 (0.40, 0.87)

0.63 (0.39, 1.01)

0.52 (0.26, 1.03)

0.47 (0.29, 0.77)

0.95 (0.51, 1.79)

0.35 (0.16, 0.73)

0.76 (0.48, 1.20)

0.78 (0.37, 1.66)

0.52 (0.33, 0.82)

0.61 (0.41, 0.90)

0.25 (0.07, 0.88)

0.79 (0.50, 1.25)

0.21 (0.05, 0.82)

0.65 (0.43, 0.97)

0.79 (0.50, 1.26)

0.44 (0.20, 0.94)

1 Hazard Ratio and 95% CI

ASNS category

Gender

Time from randomization

ECOG

Number of metastatic sites

CA19.9 level at baseline

Chemotherapy type

Response to prior therapy

I T T P O P U L A T I O N

Eryaspase Phase 2b Trial

Overall Survival Benefit Consistent Across Subgroups1

161. Hammel et al., European Journal of Cancer, 2019;

17

I T T P O P U L A T I O N

Pro

gre

ssio

n-f

ree s

urv

iva

l pro

babili

ty (

%)

0

10

20

30

40

50

60

70

80

90

100

Months0 4 6 8 10 122 14 16

No. at risk

E +CT 95 36 18 12 6 4 3 0

CT 46 9 6 1 1 1 0

Eryaspase + chemotherapy

(n=95)

Chemotherapy (n=46)

Events, n (%)

70 (73.7)

36 (78.3)

Median PFS, months

(95% CI) 2.0

(1.8–3.4)1.6

(1.4–1.8)

P value 0.006

Similar Progression-Free Survival Benefit1

44%reduction in the risk of progression

(HR, 0.56; P=0.005)

I T T P O P U L A T I O N

Eryaspase Phase 2b Trial

Events n (%) 70 (74%) 36 (78%)

OS HR (95% CI)

P-value

0.56 (0.37, 0.84)

0.005

Median PFS

(weeks)

8.6 6.9

1. Hammel et al., European Journal of Cancer, 2019;

18

47,4

11,6

23,9

6,5

0

5

10

15

20

25

30

35

40

45

50

Disease control rate Overall response rate

Pa

tie

nts

, %

Eryaspase +chemotherapy

Chemotherapy

I T T P O P U L A T I O N

Eryaspase Phase 2b Trial

new lesions

new lesions

** CR**

PD

SD

OR

PD

SD

ORPD = Progressive disease

SD = Stable disease

PR = Partial response

CR= Complete response

OR = Overall response (PR +CR)

DCR = Disease control rate (OR+SD)

OROR

SD

SD

Improved Response Rates and Fewer New Lesions1

181. Hammel et al., European Journal of Cancer, 2019;

19

No Additional Toxicity Over Chemotherapy Alone

0 10 20 30 40 50 60 70 80

Asthenia

Nausea

Anemia

Vomiting

Thrombocytopenia

Abdominal pain

Diarrhea

Decreased appetite

Pyrexia

Constipation

Neutropenia

GGT increased

Physical health deterioration

Antibody test positive

Weight decreased

Peripheral edema

Upper abdominal pain

Stomatitis

ALT increased

Hypokalemia

Neuropathy peripheral

Fatigue

Back pain

Cough

Mucosal inflammation

Alopecia

Hyperthermia

Lymphopenia

Hyperglycemia

AST increase

Anxiety

Hypoalbuminemia

Insomnia

All grade adverse events (%)

Chemotherapy

Eryaspase +chemotherapy

> Grade 3/4 >=1 SAE

50%45%

77%

86%

Patients with ≥1 Grade 3 or 4 AE

Patients with≥1 SAE

TREATMENT EMERGENT EVENTS

REGARDLESS OF RELATIONSHIP TO

STUDY DRUG

Eryaspase Phase 2b TrialI T T P O P U L A T I O N

19

20

Reference: ClinicalTrials.gov: NCT03665441

ECOG, Eastern Cooperative Oncology Group; PS, performance status

FOLFIRI, 5FU/leucovorin/irinotecan; the irinotecan can be Onivyde (nanoliposomal irinotecan or NALIRI)

03

option

Patients (N ≈ 500)

• ≥18 years

• Stage III or IV PAC

• One prior systemic

chemotherapy in

advanced setting

• Measurable disease

• ECOG PS 0 or 1

Primary endpoint

Ra

nd

om

ize

1:1

Chemotherapy

(gemcitabine+nabpaclitaxel

or FOLFIRI)

plus eryaspase

• Overall Survival

Key secondary endpoints

• Progression-free survival

• Objective response rate

• Disease control rate

• Safety and tolerability

• Quality of life

Chemotherapy alone

(gemcitabine+nabpaclitaxel

or FOLFIRI)

Stratification by ECOG PS, chemotherapy regimen

and time since diagnosis of advanced disease

TRYbeCA-1, Phase 3 trial in 2L Pancreatic Cancer Launched in 2018

Pascal Hammel Manuel HidalgoCo-PI, Weil Cornell Medicine, New York, U.S.Co-PI, Hôpital Beaujon, Paris, France

20

Trial expected to run in approximately 100 clinical sites in 11 European countries and the U.S.

21

• More than 75% of total expected projected patients enrolled

• On track for full enrollment in Q4 2020*

• Trial approved and enrolling patients in 11 countries in Europe and the United States

• 65+ clinical sites activated

• Safety data of first 150 and 320 patients reviewed by independent data monitoring committee in

October 2019 and April 2020 respectively:

• No safety issues identified

• Recommendation to continue trial as planned

• Interim analysis (for superiority) expected around year-end 2020*

• Based on comparison of OS when 2/3 of events will have occurred

• Two outcomes possible: continue as planned or stop for superiority (no futility analysis planned)

TRYbeCA-1 on Track for Complete Enrollment in 4Q20

21

*subject to COVID-19 uncertainty

22

Phase 2 proof of concept trial ongoing in Triple-Negative Breast Cancer (TNBC) in Europe

• Approximately 64 patients with newly diagnosed metastatic disease

• Randomized 1-1: chemotherapy (gemcitabine/carboplatin) +/- eryaspase

• Primary endpoint: objective response rate

• Approximately 20 sites activated

• Results expected in 2021

Phase 1 IST in 1L pancreatic cancer in the United States in preparation (N=12-18)

• Evaluation of safety of eryaspase in combination with FOLFIRINOX

• Launch of trial expected in 2H 2020

Phase 2 IST in 2L ALL in Nordic countries of Europe nearing complete enrollment (N=50)

• Interim update expected in 1H 2020, full results by year-end 2020

Broadening Scope to Other Indications

Head of the Medical Oncology

Clinic at Jules Bordet Cancer

Institute Brussels, Belgium

PI: Ahmed Awada

22

23

Own cGMP production in Europe and US, scaled

for clinical and early-commercial manufacturing

• Europe: Lyon (France)

• 12 cleanrooms

• United States: Princeton, NJ

• 16 cleanrooms, 4 equipped

Industrialized and Scalable Manufacturing

23

24

Preclinical Programs

Erymethionase, methionine-gamma-lyase encapsulated in RBC

• Promising preclinical data in gastric cancer and glioblastoma

suggest potential as a new treatment approach against cancers

that rely on methionine metabolism

• Further preclinical data show potential synergistic effect of

methionine restriction with immune checkpoint inhibitors and

asparaginase

ERYZYME, encapsulating enzymes used in certain enzyme

therapies to treat rare metabolic diseases

• E.g. Arginase-1-deficiency: preclinical data showing sustained

lowering of arginine levels with arginine deiminase encapsulated

in RBC in arginase deficient mice

Gastric adenocarcinoma

Days post-tumor implantation

Me

an t

um

or

volu

me

(m

m3+

SE

M)

0 10 20 30 40 50 60 70 80

0

200

400

600

800

1000

1200

1400

1600

1800

Vehicle

Erymethionase 80 U/kg

***

****

**

Erymethionase + PN

Tumor regression in gastric cancer model

25

Strategic Collaboration with SQZ Biotechnologies

25

• ERYTECH granted SQZ Biotechnologies, a Cambridge (MA) based cell therapy

company, an exclusive worldwide license to develop antigen-specific immune

modulating therapies employing red blood cell-based technology.

• SQZ to develop RBC-derived therapeutics to induce antigen-specific immune

modulation by combining SQZ’s Cell Squeeze® cell engineering platform with

ERYTECH’s IP and knowhow related to RBC-based therapeutics

• ERYTECH is eligible to receive:

• Upfront and potential milestone payments up to $57 million for the first product

successfully developed by SQZ under agreement

• Royalties on sales, and potential commercial milestone payments up to $50

million for each additional approved product or approved indication

26

FY 2019 Financial Results

26

In thousands of euros FY 2019 FY 2018

Revenues — —

Other income 5,283 4,447

Total operating income 5,283 4,447

Research and development (52,193) (33,467)

General and administrative (17,164) (14,600)

Total operating expenses (69,357) (48,067)

Total operating loss (64,074) (43,621)

Financial income 2,947 5,427

Financial expenses (1,533) (29)

Financial income (loss) 1,414 5,399

Loss before tax (62,660) (38,222)

Income tax 1 (2)

Net loss (62,659) (38,224)

• Net loss of €62.7 million, up €24.5 million

compared to 2018

• Cash position of €73.2 million ($82.2 million)

as of December 31, 2019, compared with

€134.4 million on December 31, 2018 and

€81.9 million at September 30, 2019.

• The €61.2 million decrease in cash position

during the twelve months of 2019 was

mostly comprised of a €43.3 million net

cash utilization in operating activities, and

€19.8 million used for investing activities,

• Cash runway confirmed into Q1 2021

Q1 2020 Financial Highlights

• As of March 31, 2020, cash and cash equivalents totaling €58.6 million (approximately $64.6 million),

• Compared with €73.2 million on December 31, 2019.

• The €14.6 million decrease in cash position in the first quarter 2020 was the result of:

– €16.7 million net cash utilization in operating activities, inline with operating plan;

– €1.1 million used for investing activities;

– €2.4 million generated in financing activities

– €0.7 million favorable currency exchange impact of the U.S. dollar against the euro

• While closely monitoring the budget impact of the COVID-19 pandemic on its operations, the Company

confirms its earlier guidance on sufficient cash position to fund operations into Q1 2021.

28

Key Milestones Anticipated over Next 12 Months

Interim update on Phase 2 IST in 2L acute lymphoblastic leukemia (ALL)

Initiation of Phase 1 IST with eryaspase in 1L pancreatic cancer

Interim (superiority) analysis in TRYbeCA-1

Full results of Phase 2 IST in 2L ALL

Interim results of Phase 1 IST in 1L pancreatic cancer

28

ERYTECH Pharma SA60 Avenue Rockefeller

69008 LyonFrance

ERYTECH Pharma Inc1 Main Street

Cambridge, MA 02142USA

www.erytech.com