424B5 1 ny20063216x1_424b5.htm 424B5

Filed Pursuant to Rule 424(b)(5)

Registration No. 333-285604

The information in this preliminary prospectus supplement is not complete and may be changed. This preliminary prospectus supplement and accompanying prospectus are not an offer to sell these securities and are not soliciting an offer to buy these securities in any jurisdiction where the offer or the sale is not permitted.

Subject to Completion, Dated May 20, 2026

PRELIMINARY PROSPECTUS SUPPLEMENT (To Prospectus Dated March 14, 2025)

€75,000,000

Ordinary Shares

(Including Ordinary Shares In the Form of American Depositary Shares)

Pre-Funded Warrants to Purchase up to Ordinary Shares

Ordinary Shares Issuable Upon Exercise of all the Pre-Funded Warrants

We are conducting a global offering (the “offering”) of ordinary shares, €0.03 nominal value per share (“ordinary shares”), and pre-funded warrants to purchase up to ordinary shares.

This global offering consists of (i) a public offering in the United States of ordinary shares to be delivered in the form of American Depositary Shares (“ADSs”), each ADS representing one ordinary share (the “U.S. offering”) and (ii) an offering outside the United States (the “European offering”) of (a) ordinary shares and (b) pre-funded warrants (for certain purchasers in lieu of ordinary shares) to purchase up to ordinary shares, such European offering being exclusively addressed to “qualified investors,” as such term is defined in Article 2(e) of the Regulation (EU) No. 2017/1129 of the European Parliament and Council of June 14, 2017, as amended. Each pre-funded warrant is exercisable for one ordinary share. This prospectus supplement also relates to the ordinary shares issuable upon the exercise of the pre-funded warrants.

Our ordinary shares are listed on the regulated market of Euronext in Paris (“Euronext Paris”) under the symbol “NANO.” Our ADSs are listed on the Nasdaq Global Select Market (“Nasdaq”) under the symbol “NBTX.” On May 19, 2026, the last reported sale price of our ordinary shares on Euronext Paris was €38.48 per ordinary share and the last reported sale price of our ADSs on Nasdaq was $46.20 per ADS. There is no established public trading market for the pre-funded warrants, and we do not expect any such market to develop. We do not intend to list the pre-funded warrants on any domestic or foreign securities exchange or nationally recognized trading system. Without an active trading market, the liquidity of the pre-funded warrants will be limited.

The total number of ordinary shares (in the form of ADSs) in the U.S. offering and ordinary shares (including those issuable upon exercise of pre-funded warrants) in the European offering is subject to reallocation between them.

Each pre-funded warrant is exercisable for one ordinary share at an exercise price of €0.03 per ordinary share. Each pre-funded warrant will be immediately exercisable at any time at the option of the holder until such pre-funded warrant is exercised in full during a period of ten years from their issuance, provided that the holder will be prohibited from exercising pre-funded warrants for ordinary shares if, as a result of such exercise, the holder, together with its affiliates and attribution parties under French law, would beneficially own more than a cap on beneficial ownership to be set by such holder of the total number of ordinary shares then issued and outstanding.

The purchase price of each ADS is $ . The purchase price of each pre-funded warrant to purchase one ordinary share is € (corresponding to $ ), which is equal to the offering price per ordinary share to be sold in this offering minus €0.03, and the exercise price of each such pre-funded warrant is €0.03 per ordinary share. This prospectus supplement also relates to the offering of the ordinary shares issuable upon exercise of the pre-funded warrants.

We are a “foreign private issuer” under applicable U.S. federal securities laws and are eligible for reduced public company reporting requirements, as described in our Annual Report (as defined below).

Investing in our securities involves risks. Please read “Risk Factors” beginning on page S-14 of this prospectus supplement and under similar headings in the documents incorporated by reference into this prospectus supplement and the accompanying prospectus for a discussion of certain risks you should consider before investing in our securities.

Neither the Securities and Exchange Commission nor any U.S. state or other securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

Per

Ordinary Share

Per ADS⁽¹⁾

Per Pre-Funded

Warrant⁽¹⁾

Total⁽¹⁾

Offering price

€

€ ($ )

Underwriting commissions⁽²⁾

€

€ ($ )

Proceeds to us (before expenses)⁽³⁾

€

€ ($ )

(1)	Reflects an exchange rate of €1.00 = $ on , 2026, as published by the European Central Bank on , 2026.

(2)	We refer you to “Underwriting” beginning on page S-24 of this prospectus supplement for additional information regarding underwriting compensation.

(3)	Does not give effect to any exercise of any pre-funded warrants being issued in this offering.

For the U.S. offering, delivery of the ADSs is expected to be made on or about , 2026, through the book-entry facilities of The Depository Trust Company, which is the business day following the date of this prospectus supplement (such settlement cycle being referred to as “T+ ”). Under Rule 15c6-1 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), trades in the secondary market generally are required to settle in one business day unless the parties to any such trade expressly agree otherwise. Accordingly, purchasers who wish to trade the ADSs on any date prior to the first business day before delivery of the ADSs will be required, by virtue of the fact that the ADSs initially will settle in T+ to specify an alternative settlement cycle at the time of any such trade to prevent a failed settlement. Purchasers of the ADSs who wish to trade the ADSs prior to the date of delivery of the ADSs should consult their own advisors. For the European offering, delivery of the ordinary shares and pre-funded warrants is expected to be made on or about , 2026 through the book-entry facilities of Euroclear France or, for the pre-funded warrants, by credit to the account of the holder(s) held by the French registrar.

We have agreed to issue, at the option of the underwriters, within 30 days from the date of the underwriting agreement to be executed between us and the underwriters, up to an aggregate of additional ordinary shares (to be delivered in the form of ADSs) to be sold to the several underwriters at the applicable offering price. If the underwriters exercise this option in full, the total underwriting commissions payable by us will be € ($ ) and the total proceeds to us, before expenses, will be € ($ ).

Joint Book-Running Managers


Jefferies	TD Cowen	Stifel

Prospectus Supplement dated , 2026


			Page
ABOUT THIS PROSPECTUS SUPPLEMENT			S-ii
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS			S-iv
PROSPECTUS SUPPLEMENT SUMMARY			S-1
RISK FACTORS			S-14
USE OF PROCEEDS			S-18
DILUTION			S-19
DESCRIPTION OF SECURITIES OFFERED			S-21
UNDERWRITING			S-24
NOTICE TO INVESTORS			S-28
TAXATION			S-34
MATERIAL CHANGES			S-45
WHERE YOU CAN FIND ADDITIONAL INFORMATION			S-45
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE			S-46
LEGAL MATTERS			S-47
EXPERTS			S-48


			Page
About This Prospectus			1
Trademarks and Service Marks			1
Market, Industry and Other Data			2
Special Note Regarding Forward-Looking Statements			3
Nanobiotix S.A.			5
Risk Factors			6
Use of Proceeds			7
Capitalization and Indebtedness			8
Description of Share Capital			9
Description of Preferred Shares			32
Description of Warrants			34
Description of American Depositary Shares			35
Selling Shareholder			47
Plan of Distribution			48
Enforcement of Civil Liabilities			50
Taxation			51
Legal Matters			51
Experts			51
Where You Can Find Additional Information			51
Incorporation of Certain Information by Reference			52
Expenses			53


	Guidance / Anticipated Timing			Anticipated Readout / Event
	H1 2027			Phase 3 data in respect of NANORAY-312
	Early 2027			Results from randomized part of CONVERGE
	2026 (completed)			First patient recruited for LUMIRAY Phase 1b clinical trial of cisplatin-eligible LA-HNSCC.
	2026-2027			Advancement of various indications being studied by MD Anderson
	2026			Completion and data for Pancreatic PDAC/BRPC
	2026			Updated data for Espohageal cancer
	2026			Completion and data for NSCLC amenable to re-irradiation
	2026			Study 1100 completion and data for locally advanced or metastatic melanoma patients (subgroup from cohort 3)


	CONVERGE			N=7
	Age, median (range)			67 (60-76)
	Sex, n (%)
	Male			6 (85.7)
	Female			1 (14.3)
	Race, n (%)
	White			3 (42.9)
	Black			3 (42.9)
	Unknown			1 (14.3)
	Smoking Status, n (%)
	Former smoker			6 (85.7)
	Current smoker			1 (14.3)
	ECOG status, n (%)
	0			3 (42.9)
	1			4 (57.1)
	Histology, n (%)
	Non-Squamous cell			4 (57.1)
	Squamous cell carcinoma			3 (42.9)
	Cancer stage at initial diagnoses
	3A			5 (71.4)
	3B			2 (28.6)
	T stage
	T1b			1 (14.3)
	T1c			1 (14.3)
	T2a			1 (14.3)
	T2b			1 (14.3)
	T4			3 (42.9)
	N stage
	N0			1 (14.3)
	N2			6 (85.7)
	M stage
	M0			7 (100.0)
	PD-L1 status, n (%)
	High (TPS ≥ 50%)			1 (14.3)
	Low (TPS 1-49%)			2 (28.6)
	Negative (TPS < 1%)			4 (57.1)


	Durvalumab	Placebo	Total
PACIFIC	N=476	N=237	N=713
Age, median (range)	64 (31-84)	64 (23-90)	64 (23-90)
Sex, n (%)
Male	334 (70.2)	166 (70.0)	500 (70.1)
Female	142 (29.8)	71 (30.0)	213 (29.9)
Race, n (%)
White	337 (70.8)	157 (66.2)	494 (69.3)
Black	12 (2.5)	2 (0.8)	14 (2.0)
Asian	120 (25.2)	72 (30.4)	192 (26.9)
Smoking Status, n (%)
Former smoker	354 (74.4)	178 (75.1)	532 (74.6)
Current smoker	79 (16.6)	38 (16.0)	117 (16.4)
Never smoked	43 (9.0)	21 (8.9)	64 (9.0)
ECOG status, n (%)
0	234 (49.2)	114 (48.1)	348 (48.8)
1	240 (50.4)	122 (51.5)	362 (50.8)
Histology, n (%)
Non-Squamous cell	252 (52.9)	135 (57.0)	387 (54.3)
Squamous cell carcinoma	224 (47.1)	102 (43.0)	326 (45.7)
Cancer stage at initial diagnoses
3A	252 (52.9)	125 (52.7)	377 (52.9)
3B	212 (44.5)	107 (45.1)	319 (44.7)
Other	12 (2.5)	5 (2.1)	17 (2.4)
PD-L1 status, n (%)
< 25%	187 (78.8)	105 (90.0)	292 (41.0)
≥ 25%	115 (47.9)	44 (36.0)	159 (22.3)
Unknown	174 (73.3)	88 (74.1)	262 (36.7)
<1% (posthoc analysis)	90 (18.9)	58 (24.5)	148 (20.8)


Nanoprimer enhances mRNA lipoplex vaccine priming, boosting effector T cell response and IFN-γ production			Nanoprimer improves the memory vaccination of mRNA lipoplex vaccines with a strong T-cell response


Nanoprimer enables OVA-peptide liposome vaccine priming, inducing strong T-cell response (Day 7) and IFN-γ production			Robust vaccination and long-term memory response are observed when the Nanoprimer is administered


		Per Ordinary Share
Offering price		€
Historical net tangible book deficit per ordinary share as of December 31, 2025	€(1.75)
Increase in net tangible book value (decrease in deficit) per ordinary share to existing shareholders attributable to investors purchasing securities in this offering
As adjusted net tangible book value per share as of December 31, 2025 after giving effect to this offering
Dilution per ordinary share to investors participating in this offering		€

SEC Form 424B5 filed by Nanobiotix S.A.