Global Development Strategy

CORPORATE PRESENTATION

1 DECEMBER 2020 IMPORTANT: You must read the following before continuing. In accessing this document, you agree to be bound by the following terms and conditions. The Presentation is not, and should not be construed as, an offer of any securities or the solicitation of an offer to subscribe for or purchase any securities. This Presentation is not to be construed as providing investment advice. The information is not directed to, or intended for distribution to or use by, any person or entity that is a citizen or resident of, or located in, any jurisdiction where such distribution or use would be contrary to law or regulation or which would require any registration or licensing within such jurisdiction. No public offering of securities may be conducted in France prior to the delivery by the AMF of an approval on a prospectus that complies with the provisions of Regulation 2017/1129. The Information is for information purposes only and does not constitute an offering document or an offer of securities to the public in the United Kingdom to which section 85 of the Financial Services and Markets Act 2000 of the United Kingdom applies. This Presentation has been prepared by Nanobiotix SA and is provisional and for information purposes only. The information presented is provided as of the date of this Presentation only and may be subject to significant changes at any time without notice. Neither the Company, nor its advisors, nor any other person is under any obligation to update such information. The information has not been subject to independent verification and is qualified in its entirety by the business, financial and other information that the Company is required to publish in accordance with the rules, regulations and practices applicable to companies listed on Euronext Paris. Please refer to the Company’s universal registration document approved by the French Financial Markets Authority (Autorité des Marchés Financiers – the “AMF”) under number R.20-010 on May 12, 2020, including in particular the risk factors therein, as well as in any other periodic report and in any other press release, which are available free of charge on the websites of the Company (www.nanobiotix.fr) and/or the AMF (www.amf-france.org). The Presentation includes information on the use of the Company’s products and its competitive position. Some of the information included in the Presentation is from third parties. While this third party information has been obtained from sources believed to be reliable, there is no guarantee of the accuracy or completeness of such data. In addition, certain of the industry and market data comes from the Company’s own internal research and estimates based on the knowledge and experience of the Company’s management. While Nanobiotix believes that such research and estimates are reasonable and reliable, they, and their underlying methodology and assumptions, have not been verified by any independent source for accuracy or completeness and are subject to change without notice. Accordingly, undue reliance should not be placed on any of the industry, market or competitive position data contained in the Presentation. The Presentation contains certain forward-looking statements. All statements in the Presentation other than statements of historical fact are or may be deemed to be forward looking statements. These statements are not guarantees of the Company’s future performance. These forward-looking statements relate without limitation to the Company’s future prospects, developments, marketing strategy regulatory calendar, clinical milestones, assumptions and hypothesis, clinical development approach and financial requirements and are based on analyses of earnings forecasts and estimates of amounts not yet determinable and other financial and non-financial information. Such statements reflect the current view of the Company's management, and are subject to a variety of risks and uncertainties as they relate to future events and are dependent on circumstances that may or may not materialize in the future. Forward-looking statements cannot, under any circumstance, be construed as a guarantee of the Company’s future performance as to strategic, regulatory, financial or other matters, and the Company’s actual performance, including its financial position, results and cash flow, as well as the trends in the sector in which the Company operates, may differ materially from those proposed or reflected in the forward-looking statements contained in this Presentation. Even if the Company’s performance, including its financial position, results, cash-flows and developments in the sector in which the Company operates were to conform to the forward-looking statements contained in this Presentation, such results or developments cannot be construed as a reliable indication of the Company’s future results or developments. The Company expressly declines any obligation to update or to confirm any prospective information in order to reflect an event or circumstance that may occur after the date of this Presentation.

DECEMBER 2020 Our vision is to change the face of treatment for millions of patients by bringing nanophysics to the heart of the cell.

DECEMBER 2020 Potential First-in-class Oncology Product With Potential To Address More Than 10M Patients Who Are 1 Candidates For Radiotherapy

Established Human Proof-of-concept As A Single Agent In Soft Tissue Sarcoma Randomized Phase III 2 Trial, And Positive Preliminary Data In Advanced Head and Neck And Liver Cancer

3 Phase III Trial For Underserved Head & Neck Cancer Population Agreed With FDA To Be Started

First Clinical Data In Anti-PD-1 Refractory Patients Showing The Potential To Transform Non- 4 responders Into Responders

Clinical Value In IO And Numerous Phase I Or II Studies Underway With MD Anderson Represent 5 Additional Near Term Value Drivers

Highly Experienced Management Team With Broad Expertise Across Clinical Development And 6 Commercialization

DECEMBER 2020 THE UNMET NEED

Millions of patients receive radiotherapy each year but still have significant unmet medical needs.

DECEMBER 2020 RECEIVING RTx NUMBER OF PATIENTS W/ RTX 87% Breast cancer 1,800,000 77% Lung cancer 1,600,000 60% 74% H&N 700,000 18M RTx 58% Prostate 740,000 new patients 60% Rectum 420,000 per year 49% Pancreas 225,000 diagnosed 80% CNS 237,000 with cancer worldwide … …

DECEMBER 2020

Source: * World Health Organization (2014); **RADIATION THERAPY EQUIPMENT – A global strategic business report 08/06 ; Delaney et al. 2015; Globocan 2018 Inadequate local control (Local invasion or systemic expansion)

Inadequate systemic control 60% (metastatic patients) 18M RTx new patients Unfavorable safety profile per year (dose de-escalation/re-irradiation) diagnosed with cancer worldwide

DECEMBER 2020

Source: * World Health Organization (2014); **RADIATION THERAPY EQUIPMENT – A global strategic business report 08/06 ; POTENTIAL FIRST-IN-CLASS RADIOENHANCER

NBTXR3 is a potential first-in-class, universal solution to transform radiotherapy into nanoradiotherapy.

DECEMBER 2020 • Potential First-in-class Radioenhancer

• Aqueous suspension of inorganic crystalline hafnium oxide (HfO2) nanoparticles

• Nanosized to enter the cell and designed to strongly absorb ionizing radiation

DECEMBER 2020 Dose Dose

dose* around nanoparticles Usual dose delivered Radiotherapy in the cell Radiotherapy with NBTXR3 Usual dose delivered in the cell

Clusters of XRay XRay Nanoparticles

Local absorption 2 µm of energy

*Dose enhancement determined by Monte Carlo simulation (CEA Saclay, France).

*Note: Dose enhancement determined by monte carlo simulation (CEA Saclay, France) DECEMBER 2020 11

Local control

Direct cell death

NBTXR3 X-Rays (apoptosis, necrosis)

Injected lesion Injected IRRADIATED lesion IRRADIATED Potential for Local and Systemic Control

Maggiorella et al. Future Oncol. 2012;8(9):1167-1181; Thariat et al. Int J Radiat Oncol Biol Phys. 2019;105(1S):E651. Abs 3513.; Marill et al. Radiother Oncol. 2019;141:262-266; Zhang et al. Int J Nanomedicine. 2020;15:3843-3850; Shen et al. J Clin Oncol. 2020;38(15_suppl):TPS3173-TPS.

The scientific information discussed in this presentation related to NBTXR3 is preliminary and investigative. NBTXR3 is not approved by the U.S. Food and Drug Administration; therefore, no conclusions can nor should be drawn regarding the safety or effectiveness of the investigational product.

DECEMBER 2020 INDICATION* IND PHASE I PHASE II PHASE III

Soft Tissue Sarcoma of Extremity & Trunk Wall*

Head & Neck Locally Advanced Cancer

Development Liver Hepatocellular Cancer & Overview Liver Metastases

Prostate Adenocarcinoma

NBTXR3 Pancreas Locally Advanced or activated by Borderline Resectable

RT alone NSCLC Re-Irradiation

*In addition, three NBTXR3 clinical trials are currently being run in Asia by PharmaEngine, Inc. (‘‘PharmaEngine’’). NSCLC = non-small cell lung cancer. 1. Study NCT03589339. Clinicaltrials.gov website; 2. Study NCT01946867. Clinicaltrials.gov website; 3. Study NSCT02721056. Clinical Trials.gov website; 4. Study NCT02805894. Clinicaltrials.gov website; 5. Study NCT02465593. Clinicaltrials.gov website; 6. Study NCT02901483. Clinicaltrials.gov website; 7. Study NCT02379845. Clinicaltrials.gov website; 8. In House Data, M.D. Anderson Cancer Center Trial; 9. Study NCT04505267. Clinicaltrials.gov website; 10 Study NCT04484909. Clinicaltrials.gov website; *Approval in EU only.

Soft Tissue Sarcoma of Extremity & Trunk Wall*

Head & Neck Locally CLINICALAdvanced Cancer PROOF OF CONCEPT ESTABLISHED

Development Liver IN A RANDOMIZED PHASE II/III TRIAL IN SOFT TISSUE SARCOMA Hepatocellular Cancer & Overview Liver Metastases

ProstateNBTXR3, a potential first-in-class radioenhancer Adenocarcinomahafnium oxide nanoparticle, plus radiotherapy versus radiotherapy alone in patients with locally advanced soft-tissue sarcoma (Act.In.Sarc): a NBTXR3 Pancreasmulticentre, phase 2-3, randomised, controlled trial. Locally Advanced or activated by Borderline Resectable

RT alone NSCLC Re-Irradiation

PUBLISHED IN LANCET ONCOL. 2019 MOA clinically *In addition, three NBTXR3 clinical trials are currently being run in Asia by PharmaEngine, Inc. (‘‘PharmaEngine’’). PRIMARY ENDPOINT MET NSCLC = non-small cell lung cancer. 1. Study NCT03589339. Clinicaltrials.gov website; 2. Study NCT01946867. Clinicaltrials.gov website; 3. Study NSCT02721056. Clinical Trials.gov website; 4. Study NCT02805894. Clinicaltrials.gov website; 5. Study NCT02465593. Clinicaltrials.gov website; 6. Study NCT02901483. Clinicaltrials.gov website; 7. Study demonstrated NCT02379845. Clinicaltrials.gov website; 8. In House Data, M.D. Anderson Cancer Center Trial; 9. Study NCT04505267. Clinicaltrials.gov website; 10 Study NCT04484909. Clinicaltrials.gov website; *Approval in EU only. The scientific information discussed in this presentation related to NBTXR3 is preliminary and investigative. NBTXR3 is not approved by the U.S. Food and Drug Administration; therefore, no conclusions can nor should be drawn regarding the safety or effectiveness of the investigational product. DECEMBER 2020 INDICATION* IND PHASE I PHASE II PHASE III

Soft Tissue Sarcoma of Extremity & Trunk Wall*

Head & Neck Locally Advanced Cancer

Development A targetLiver population with high unmet needs: frail elderly H&N patients that Hepatocellular Cancer & Overview are ineligibleLiver Metastases for cisplatin and intolerant to cetuximab. low RR, short PFS of ~7.3 months, short OS of ~12 months* Prostate Adenocarcinoma Positive phase I escalation results NBTXR3 Pancreas Well toleratedLocally Advanced & best or ORR = 69%) activated by Borderline Resectable Fast Track designation obtained in February 2020 RT alone NSCLC Re-Irradiation New positive phase I expansion results presented at ASTRO (September 2020) H&N to establish Well tolerated and promising efficacy (Best ORR = 84%) NSCLC = non-small cell lung cancer. 1. Study NCT03589339. Clinicaltrials.gov website; 2. Study NCT01946867. Clinicaltrials.gov website; 3. Study NSCT02721056. Clinical Trials.gov high medical website; 4. Study NCT02805894. Clinicaltrials.gov website; 5. Study NCT02465593. Clinicaltrials.gov website; 6. Study NCT02901483. Clinicaltrials.gov website; 7. Study NCT02379845. Clinicaltrials.gov website; 8. In House Data, M.D. Anderson Cancer Center Trial; 9. Study NCT04505267. Clinicaltrials.gov website; 10 Study NCT04484909. value Clinicaltrials.govPhase website; III *Approval design in EU only.reviewed by FDA / To be started

*ref: claims data presented at MHNCS 2020 and Amini et al., Bourhis et al. and Moye et al. DECEMBER 2020 INDICATION* IND PHASE I PHASE II PHASE III

Soft Tissue Sarcoma of Extremity & Trunk Wall*

Head & Neck Locally Advanced Cancer

Development Liver Hepatocellular Cancer & Overview LiverH&N Metastases PI: Dose escalation and expansion Frail elderly patient not eligible for chemo Prostate Adenocarcinoma Dose escalation Dose expansion N= 16 evaluable patients 1 2 NBTXR3 Pancreas N= 31 evaluable patients Locally Advanced or activated by BorderlineCR 69% Resectable at dose levels ≥ 10% Primary lesion CR 68.0%*

RT alone NSCLC Re-Irradiation H&N to establish

NSCLC = non-small cell lung cancer. 1. Study NCT03589339. Clinicaltrials.gov website; 2. Study NCT01946867. Clinicaltrials.gov website; 3. Study NSCT02721056. Clinical Trials.gov high medical website; 4. Study NCT02805894. Clinicaltrials.gov website; 5. Study NCT02465593. Clinicaltrials.gov website; 6. Study NCT02901483. Clinicaltrials.gov website; 7. Study NCT02379845. Clinicaltrials.gov website; 8. In House Data, M.D. Anderson Cancer Center Trial; 9. Study NCT04505267. Clinicaltrials.gov website; 10 Study NCT04484909. value Clinicaltrials.gov website; *ApprovalHigh in EU response only. rate and potential to impact PFS and OS * Update from ASTRO 2020 The scientific information discussed in this presentation related to NBTXR3 is preliminary and investigative. NBTXR3 is not approved by the U.S. Food and Drug Administration; therefore, no conclusions can nor should be drawn regarding the safety or effectiveness of the investigational product. DECEMBER 2020 Summary data from certain published scientific literature relating to head and neck trials evaluating radiotherapy combined with cisplatin. Harrington et al. 2013 Harrington et al. RT + Cisplatin 2013 N=33 RT + Cisplatin N=26µ Median age (years) 57

ECOG (%) Best Observed Target 6 months post 0 (KPS 100) 52 Lesion Response (%) CRTµ 1 (KPS 80-90) 48 2 (KPS 60-70) 0 ORR (CR+PR) 58 Stage (%) CR 31 III 21 IVA/B 79 PR 27 Primary tumor site (%) Oral cavity 9 SD 0 Oropharynx 61 Hypopharynx 21 PD 42 Larynx 9 Missingµ 0 HPV status OPSCC (%) HPV+ 13 HPV- 87 µ evaluable patients only, response rates adjusted excluding 7 missing patients Harrington et al. EJC 2013

This historical literature is presented solely to illustrate the current market opportunity arising from existing application of the standard treatment. Because of the unique design of such studies applied to specific patient populations, no comparison with any of our clinical trials is possible and none should be inferred from this background data. DECEMBER 2020 Summary data from certain published scientific literature relating to head and neck cancer trials evaluating radiotherapy combined with cetuximab and induction chemotherapy.

E1308 Study E1308 Study IC+IMRT+Cetux IC+IMRT+Cetux N=80§ N=80§ Median age (years) 57

Best Observed Target 3-6 months post ECOG Lesion Response (%) EoT 0 (KPS 100) 91 1 (KPS 80-90) 9 2 (KPS 60-70) - ORR (CR+PR) 95 CR 49 Stage (%) III 15 PR 46 IVA/B 85

Primary tumor site (%) SD 1 Oral cavity - PD 0 Oropharynx 100 Unevaluable 4 HPV status OPSCC (%) HPV+ 100 § evaluable patients HPV- -

Marur et al. JCO 2017 This historical literature is presented solely to illustrate the current market opportunity arising from existing application of the standard treatment. Because of the unique design of such studies applied to specific patient populations, no comparison with any of our clinical trials is possible and none should be inferred from this background data. DECEMBER 2020 102 dose 102 dose expansion 102 dose expansion RT + NBTXR3 expansion RT + NBTXR3 N=31 (evaluable) RT + NBTXR3 HPV- OPSCC N=31 (evaluable) (N=7) Median age (years) 70.7

Best Observed Target 3-6 months post 3-6 months post ECOG (%) Lesion Response (%) EoT EoT 0 (KPS 100) 23 1 (KPS 80-90) 65 2 (KPS 60-70) 12 ORR (CR+PR) 84 100 Stage (%) CR 68 86 III 12 PR 16 14 IVA/B 79 Primary tumor site (%) Oral cavity 53 SD 16 0 Oropharynx 47 PD 0 0 Hypopharynx - Larynx - Missingµ 0 0 HPV status OPSCC (%) HPV+ 45 HPV- 50

This historical literature is presented solely to illustrate the current market opportunity arising from existing application of the standard treatment. Because of the unique design of such studies applied to specific patient populations, no comparison with any of our clinical trials is possible and none should be inferred from this background data. DECEMBER 2020 102 dose 102 dose 102 dose expansion expansion expansion RT + NBTXR3 RT + NBTXR3 RT + NBTXR3 N=31 (evaluable) N=31 HPV+ OPSCC (evaluable) (N=7) Median age (years) 70.7

Best Observed Target 3-6 months 3-6 months ECOG Lesion Response (%) post EoT post EoT 0 (KPS 100) 23 1 (KPS 80-90) 65 2 (KPS 60-70) 12 ORR (CR+PR) 84 100 CR 68 100 Stage (%) III 12 PR 16 0 IVA/B 79

Primary tumor site (%) SD 16 0 Oral cavity 53 PD 0 0 Oropharynx 47 Unevaluable 0 0 HPV status OPSCC (%) HPV+ 45 § evaluable patients HPV- 50

Soft Tissue Sarcoma of Extremity & Trunk Wall*

Head & Neck Locally Advanced Cancer

Development Liver Hepatocellular Cancer & Overview Liver Metastases

Prostate Adenocarcinoma

NBTXR3 Pancreas Locally Advanced or activated by Borderline Resectable

RT alone NSCLC Re-Irradiation Moving forward NSCLC = non-small cell lung cancer. 1. Study NCT03589339. Clinicaltrials.gov website; 2. Study NCT01946867. Clinicaltrials.gov website; 3. Study NSCT02721056. Clinical Trials.gov website; 4. Study NCT02805894. Clinicaltrials.gov website; 5. Study NCT02465593. Clinicaltrials.gov website; 6. Study NCT02901483. Clinicaltrials.gov website; 7. Study with PIII NCT02379845. Clinicaltrials.gov website; 8. In House Data, M.D. Anderson Cancer Center Trial; 9. Study NCT04505267. Clinicaltrials.gov website; 10 Study NCT04484909. Clinicaltrials.gov website; *Approval in EU only.

DECEMBER 2020 The scientific information discussed in this presentation related to NBTXR3 is preliminary and investigative. NBTXR3 is not approved by the U.S. Food and Drug Administration; therefore, no conclusions can nor should be drawn regarding the safety or effectiveness of the investigational product. INDICATION* IND PHASE I PHASE II PHASE III

Soft Tissue Sarcoma of Extremity & Trunk Wall*

Head & Neck Locally Advanced Cancer

Development Liver Hepatocellular Cancer & Overview Liver Metastases

HCCProstate AND LIVER METASTASES PI: Dose escalation Adenocarcinoma

NBTXR3 Pancreas Locally Advanced or activated by Borderline Resectable

RT alone NSCLC Re-Irradiation

NSCLC = non-small cell lung cancer. 1. Study NCT03589339. Clinicaltrials.gov website; 2. Study NCT01946867. Clinicaltrials.gov website; 3. Study NSCT02721056. Clinical Trials.gov website; 4. Study NCT02805894. Clinicaltrials.gov website; 5. Study NCT02465593. Clinicaltrials.gov website; 6. Study NCT02901483. Clinicaltrials.gov website; 7. Study NCT02379845. Clinicaltrials.gov website; 8. In House Data, M.D. Anderson Cancer Center Trial; 9. Study NCT04505267. Clinicaltrials.gov website; 10 Study NCT04484909. *ConsideredClinicaltrials.gov as SD by investigator. website; **Considered *Approval as PR byin investigator. EU only. Note:†Two patients, one at each level 4 and level 5 (i.e.,NBTXR3 dose of 33% and 42% of baseline tumor volume, respectively), were not evaluable. ††One patient at level 1 (i.e., NBTXR3 dose of 10% of baseline tumor volume) received a liver transplant and was thus not evaluated; one patient at level 3 (i.e., NBTXR3 dose of 22% of baseline tumor volume) died before the EoT period.

The scientific information discussed in this presentation related to NBTXR3 is preliminary and investigative. NBTXR3 is not approved by the U.S. Food and DECEMBER 2020 Drug Administration; therefore, no conclusions can nor should be drawn regarding the safety or effectiveness of the investigational product. Lesion Size Decrease

Direct cell death

X-Rays (apoptosis, necrosis) Injected lesion Injected

NBTXR3 lesion IRRADIATED Tumor antigen

Potential for Dendritic cell Local and activation

Systemic Injected Control - Local Effect

Non CD4 & CD8 IRRADIATEDlesion - T cell activation

NON Systemic Effect

Head & Neck Inoperable Locoregional Development Recurrent (Re-Irradiation) Head & Neck Overview R/M with Limited PD-L1 expression or refractory

NBXTR3 +Combination with CPi

ORR 13-22% Overall Survival Progression Free Survival * Burtness B, et al. “Pembrolizumab alone or with chemotherapy versus cetuximab with chemotherapy for recurrent or metastatic squamous cell carcinoma of the head and neck (KEYNOTE-048): a randomised, open-label, phase 3 study.” Lancet. 2019 Nov 23;394(10212):1915-1928. DECEMBER 2020 Primary resistant patients

Secondary resistant patients Responders

* Burtness B, et al. “Pembrolizumab alone or with chemotherapy versus cetuximab with chemotherapy for recurrent or metastatic squamous cell carcinoma of the head and neck (KEYNOTE-048): a randomised, open-label, phase 3 study.” Lancet. 2019 Nov 23;394(10212):1915-1928. DECEMBER 2020 Phase I study of intratumoral NBTXR3 in combination with anti-PD-1 in patients with advanced cancers

Colette Shen1, Jessica Frakes2, Jiaxin Niu3, Jared Weiss1, Jimmy Caudell2, Katherine Jameson4, Patricia Said4, Tanguy Seiwert5

1-University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA; 2-Moffitt Cancer Center, Tampa, Florida, USA; 3-Banner MD Anderson Cancer Center, Gilbert Arizona, USA; 4-Nanobiotix, Paris, France; 5-Johns Hopkins Medicine, Baltimore, Maryland, USA

DECEMBER 2020 Study 1100: A phase I study of NBTXR3 activated by radiotherapy for patients with advanced cancers treated with an anti-PD-1 therapy.

HeadHNSCC and –NeckCohort cancers 1 LungLung Metsmets – Cohort 2 LiverLiver metsMets – Cohort 3

• Inoperable LRR or R/M HNSCC • Cancer metastasized to the lung • Cancer metastasized to the liver • Tumor in previously irradiated field • Tumor not previously irradiated • Tumor not previously irradiated • Amenable to re-irradiation • Indicated to receive anti-PD-1 • Indicated to receive anti-PD-1 • Anti-PD-1 naïve or non-responder • Anti-PD-1 naïve or non-responder • Anti-PD-1 naïve or non-responder

DECEMBER 2020 Across *ALL* Cohorts – Participants are either anti-PD-1 naïve or anti-PD-1 resistant (primary or secondary) as per SITC guidelines

NAÏVE PATIENTS A. Has not received priori anti-PD-1 therapy (i.e. anti-PD-1 naïve), or;

RESISTANT TO ANTI-PD-1 PATIENTS (primary and secondary) A. Has received prior anti-PD-1 therapy and meets criteria consistent with anti-PD-1 primary resistance (i.e. anti-PD-1 non-responder), or A. Note: Participants with primary resistance have prior anti-PD-1 exposure for between 6 weeks and 6 months as well as a best overall response of Progressive Disease or Stable Disease.

B. Has received prior anti-PD-1 therapy and meets criteria consistent with anti-PD-1 secondary resistance (i.e., anti-PD- 1 non responder) A. Note: Participants with secondary resistance have prior anti-PD-1 exposure for greater than 6 months as well as disease progression after best overall response (i.e., Complete Response or Partial Response, or >6 months Stable Disease) while still on active therapy.

Kluger HM, Tawbi HA, Ascierto ML, Bowden M, Callahan MK, Cha E, et al. Defining tumor resistance to PD-1 pathway blockade: recommendations from the first meeting of the SITC Immunotherapy Resistance Taskforce. J Immunother Cancer. 2020;8(1).

DECEMBER 2020 Cohort 1 – HNSCC Cohort 2 – Lung mets Cohort 3 – Liver mets n=3 n=4 n=2 Any Grade Grade Grade Grade Any Grade Grade Grade Grade Any Grade Grade Grade Grade Grade 1-2 3 4 5 Grade 1-2 3 4 5 Grade 1-2 3 4 5 All AE 3 3 1 1 1 4 4 2 1 1 2 2 1 0 0 AE related to NBTXR3 or 2 2 1 1 1 0 0 0 0 0 2 2 1 0 0 injection procedure AE reated to RTX 2 2 1 0 0 3 3 0 0 0 2 2 1 0 0 AE related to anti-PD-1 2 1 1 1 1 1 1 0 0 0 0 0 0 0 0 All SAE 1 0 0 1 1 2 2 0 0 0 0 0 0 0 0 SAE related to NBTXR3 or 1 0 0 1 1 0 0 0 0 0 0 0 0 0 0 injection procedure Hyperglycaemia* 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 Pneumonitis* 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 SAE reated to RTX 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 SAE related to anti-PD-1 1 0 0 1 1 0 0 0 0 0 0 0 0 0 0 Diabetic ketoacidosis 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 Hyperglycaemia* 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 Acute kidney injury 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 Pneumonitis* 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 Number of patient with at least one AE, incidence calculated on a given category. *Possibly related to NBTXR3 and related to anti-PD-1. AE, adverse event; RTX, radiotherapy; SAE, serious adverse event. Cut-off date: 01OCT2020

DECEMBER 2020 Study 1100:Anti Perc-ePDnt C-1h aNaïvenge Over Time StudyAnti 110-0PD: Pe-r1c eNonnt C-hResponderange Over Time Overall Response Overall Response

50 50

Progressive Progressive

, )

Disease ) Disease

(

Stable Stable

n 0

Disease Disease

n n

i Partial -50 i Partial

-50

Response e Response

a h

Complete h Complete C -100 Response C -100 Response 0 100 200 250 500 -50 0 50 100 150 200 Study Day Study Day

0001, Naïve 0012, Naïve 0004, NR 0008, NR 0014, NR 0005, NR 0011, NR 0016, NR NR = non-responder In house data. Date data Censored (October 09 2020) 0013, NR

DECEMBER 2020 Stage IV NSCLC – non responder Stage IV HNSCC – non responder (011) Stage IV NSCLC – non responder (016) Stage II HNSCC – non responder (008) (005)

confirmed unconfirmed unconfirmed

* *

1 NR patients had 3/4 NR patients experienced tumor delayed tumor regression reduction in lesions that did not 5-6 months after receive R3 RT+NBTXR3 treatment * Lesion may have received low-dose radiation due to vicinity to targeted treatment area

DECEMBER 2020

In house data. Date data censored (October 09 2020). For illustration:

3/7 non responders have responded.

6/7 has experienced tumor reduction.

3/4 non-injected local and/or distant tumor reductions.

2/2 of potential responders responded.

DECEMBER 2020 DECEMBER 2020 INDICATION* IND PHASE I PHASE II PHASE III

+CHEMOTHERAPY

Esophagus Adenocarcinoma Development Overview

NBXTR3 activated by RT +Combination with Chemo *In addition, three NBTXR3 clinical trials are currently being run in Asia by PharmaEngine, Inc. (‘‘PharmaEngine’’). NSCLC = non-small cell lung cancer. 1. Study NCT03589339. Clinicaltrials.gov website; 2. Study NCT01946867. Clinicaltrials.gov website; 3. Study NSCT02721056. Clinical Trials.gov website; 4. Study NCT02805894. Clinicaltrials.gov website; 5. Study NCT02465593. Clinicaltrials.gov website; 6. Study NCT02901483. Clinicaltrials.gov website; 7. Study NCT02379845. Clinicaltrials.gov website; 8. In House Data, M.D. Anderson Cancer Center Trial; 9. Study NCT04505267. Clinicaltrials.gov website; 10 Study NCT04484909. Clinicaltrials.gov website; *Approval in EU only. The scientific information discussed in this presentation related to NBTXR3 is preliminary and investigative. NBTXR3 is not approved by the U.S. Food and Drug Administration; therefore, no conclusions can nor should be drawn regarding the safety or effectiveness of the investigational product. DECEMBER 2020 Expected Newsflow

DECEMBER 2020 INDICATION* EXPECTED NEWSFLOW

Soft Tissue Sarcoma Post-registrational trial in EU: Launch expected in H2 2021; Commercialization strategy to of Extremity & Trunk Wall* be evaluated based on Study 312 data

Phase III: First patient injected (FPI) expected in 2021. Futility analysis expected 18 months Head & Neck after FPI; interim analysis expected 24-30 months after FPI. Locally Advanced Cancer EU Phase I expansion: Results update by Q2 2021

Liver Hepatocellular Cancer & Final presentation of phase I results by Q1 2021. Next steps to be defined post Study 312 Newsflow Liver Metastases launch

Prostate Adenocarcinoma Phase I/II: Currently under management's review

NBTXR3 Pancreas MDA Phase I: Recruitment ongoing. Updates to be provided as they are made Locally Advanced or activated by Borderline Resectable available by MD Anderson

RT alone NSCLC MDA Phase I: Expected study launch by H1 2021. Updates to be provided as Re-Irradiation they are made available by MD Anderson

*In addition, three NBTXR3 clinical trials are currently being run in Asia by PharmaEngine, Inc. (‘‘PharmaEngine’’).

NSCLC = non-small cell lung cancer. 1. Study NCT03589339. Clinicaltrials.gov website; 2. Study NCT01946867. Clinicaltrials.gov website; 3. Study NSCT02721056. Clinical Trials.gov website; 4. Study NCT02805894. Clinicaltrials.gov website; 5. Study NCT02465593. Clinicaltrials.gov website; 6. Study NCT02901483. Clinicaltrials.gov website; 7. Study NCT02379845. Clinicaltrials.gov website; 8. In House Data, M.D. Anderson Cancer Center Trial; 9. Study NCT04505267. Clinicaltrials.gov website; 10 Study NCT04484909. Clinicaltrials.gov website; *Approval in EU only. The scientific information discussed in this presentation related to NBTXR3 is preliminary and investigative. NBTXR3 is not approved by the U.S. Food and Drug Administration; therefore, no conclusions can nor should be drawn regarding the safety or effectiveness of the investigational product. DECEMBER 2020 INDICATION* EXPECTED NEWSFLOW

Recurrent Head & Neck, Lung or Liver Phase I/II: results update by Q2 2021. Metastasis

Head & Neck MDA Phase II: Expected launch and FPI by H1 2021. Updates to be provided Inoperable Locoregional Recurrent (Re-Irradiation) as they are made available by MD Anderson

Head & Neck MDA Phase II: Expected launch and FPI expected by H1 2021. Updates to be Newsflow R/M with Limited PD-L1 provided as they are made available by MD Anderson expression or refractory

Advanced Solid Tumors with Lung or MDA Phase I: Expected launch and FPI expected in 2021. Updates to be Liver Metastasis provided as they are made available by MD Anderson NBTXR3 with anti-CTLA-4 and anti- activated by PD-1/L1 plus RadScopalTM RT +Combination with CPi

*In addition, three NBTXR3 clinical trials are currently being run in Asia by PharmaEngine, Inc. (‘‘PharmaEngine’’).

Esophagus MDA Phase I: FPI expected by H1 2021. Updates to be provided as they are Adenocarcinoma made available by MD Anderson

Newsflow

NBTXR3 activated by RT +Combination with Chemo *In addition, three NBTXR3 clinical trials are currently being run in Asia by PharmaEngine, Inc. (‘‘PharmaEngine’’).

DECEMBER 2020 6 months to June 30 FINANCIALS in K€ 2020 2019 Total revenue and other income 1,448 1,823 Share capital breakdown (as of December 2020) based Operating revenues 37 37 on 34,432,122 shares Other income 1,411 1,786

Research & Development (R&D) expenses (13,077) (13,380) Selling, General and Administrative (SG&A) costs (6,755) (8,910) Total operating expenses (19,832) (22,290) 40% Institutional investors Operating income (18,384) (20,467) Family offices Financial income 234 724 55% Management and employees Financial expenses (2,428) (4,176) Retail and other

Net financial income (2,194) (3,452) Income tax (1) - 4% 1% Net loss for the period (20,579) (23,920)

Cash availability as of September 30, 2020 amounted to €42.4M + €82.8M from NASDAQ Listing in December 2020

DECEMBER 2020 [email protected] 41