# EDGAR Filing Document

**Accession Number:** 0001501697
**File Stem:** 0001501697-25-000016
**Filing Date:** 2025-9
**Character Count:** 18066
**Document Hash:** 8544c8d75523abd7875635f407ff9f7c
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001501697-25-000016.hdr.sgml**: 20250910

**ACCESSION NUMBER**: 0001501697-25-000016

**CONFORMED SUBMISSION TYPE**: S-8

**PUBLIC DOCUMENT COUNT**: 5

**FILED AS OF DATE**: 20250910

**DATE AS OF CHANGE**: 20250910

**EFFECTIVENESS DATE**: 20250910

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** X4 Pharmaceuticals, Inc
- **CENTRAL INDEX KEY:** 0001501697
- **STANDARD INDUSTRIAL CLASSIFICATION:** BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 273181608
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** S-8
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 333-290155
- **FILM NUMBER:** 251306024

**BUSINESS ADDRESS:**
- **STREET 1:** 61 NORTH BEACON STREET
- **STREET 2:** 4TH FLOOR
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02134
- **BUSINESS PHONE:** 857-529-8300

**MAIL ADDRESS:**
- **STREET 1:** 61 NORTH BEACON STREET
- **STREET 2:** 4TH FLOOR
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02134

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Arsanis, Inc.
- **DATE OF NAME CHANGE:** 20100920

**As filed with the Securities and Exchange Commission on September 10, 2025**

**Registration No. 333-**

**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION**

**WASHINGTON, DC 20549**

**FORM S-8**

**REGISTRATION STATEMENT**

***UNDER***

***THE SECURITIES ACT OF 1933***

***____________________________________________***

**X4 Pharmaceuticals, Inc.**

**(Exact name of registrant as specified in its charter)**

___________________________________________

---

| | |
|:---|:---|
| **Delaware** | **27-3181608** |
| (State or Other Jurisdiction of<br>Incorporation or Organization) | (I.R.S. Employer<br>Identification No.) |
| **61 North Beacon Street, 4th Floor**<br>**Boston, Massachusetts** | **02134** |
| (Address of Principal Executive Offices) | (Zip Code) |

---

**X4 Pharmaceuticals, Inc. Amended and Restated 2019 Inducement Equity Incentive Plan**

**(Full title of the plan)**

**Adam R. Craig, M.D., Ph.D.**

**Executive Chairman**

**X4 Pharmaceuticals, Inc.**

**61 North Beacon Street, 4th Floor**

**Boston, MA 02134**

**(857) 529-8300**

**(Name, address, including zip code, and telephone number, including area code, of agent for service)**

_________________________________

***Copies to:***

**Ryan A. Murr**

**Melanie Neary**

**Gibson, Dunn & Crutcher LLP**

**One Embarcadero Center, Suite 2600**

**San Francisco, CA 94111-3715**

**Telephone: (415) 393-8200**

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company" and "emerging growth company" in Rule 12b-2 of the Exchange Act.

---

| | | | |
|:---|:---|:---|:---|
| Large accelerated filer | ☐ | Accelerated filer | ☐ |
| Non-accelerated filer | ☒ | Smaller reporting company | ☒ |
| | | Emerging growth company | ☐ |

---

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

------

**INCORPORATION OF DOCUMENTS BY REFERENCE**

This Registration Statement on Form S-8 is being filed for the purpose of increasing the number of securities of the same class as other securities for which a Registration Statement on Form S-8 of the Registrant relating to the same employee benefit plan is effective. Accordingly, pursuant to General Instruction E to Form S-8, this Registration Statement incorporates by reference the contents of (i) the Registration Statement on Form S-8 (File No. 333-233162) filed with the Securities and Exchange Commission ("**SEC**") on <u>[August 9, 2019](https://www.sec.gov/Archives/edgar/data/1501697/000119312519217396/d789108ds8.htm)</u> relating to the Registrant's 2019 Inducement Equity Incentive Plan (as amended and restated from time to time, the "**Inducement Plan**"); (ii) the Registration Statement on Form S-8 (File No. 333-237164) filed with the SEC on <u>[March 13, 2020](https://www.sec.gov/Archives/edgar/data/1501697/000119312520072921/d884915ds8.htm)</u> relating to the Inducement Plan and certain other employee benefit plans of the Registrant; (iii) the Registration Statement on Form S-8 (File No 333-254618) filed with the SEC on <u>[March 23, 2021](https://www.sec.gov/Archives/edgar/data/1501697/000162828021005363/a032021s-8.htm)</u> relating to the Inducement Plan and certain other employee benefit plans of the Registrant; (iv) the Registration Statement on Form S-8 (File No 333-263430) filed with the SEC on <u>[March 10, 2022](https://www.sec.gov/Archives/edgar/data/1501697/000162828022005734/a032022s-8.htm)</u> relating to the Inducement Plan and certain other employee benefit plans of the Registrant; (v) the Registration Statement on Form S-8 (File No 333-269335) filed with the SEC on <u>[January 20, 2023](https://www.sec.gov/Archives/edgar/data/1501697/000162828023001353/a032023s-8.htm)</u> relating to the Inducement Plan and certain other employee benefit plans of the Registrant; (vi) the Registration Statement on Form S-8 (File No 333-273960) filed with the SEC on <u>[August 14, 2023](https://www.sec.gov/Archives/edgar/data/1501697/000162828023029154/a082023s-8.htm)</u> relating to the Inducement Plan and certain other employee benefit plans of the Registrant; (vii) the Registration Statement on Form S-8 (File No 333-282513) filed with the SEC on <u>[October 4, 2024](https://www.sec.gov/Archives/edgar/data/1501697/000162828024042323/a092024s-8.htm)</u> relating to the Inducement Plan, and the Registration Statement on Form S-8 (File No. 333-286107) filed with the SEC on <u>[March 26, 2025](https://www.sec.gov/Archives/edgar/data/1501697/000162828025014806/a032025s-8.htm)</u> relating to the Inducement Plan, in each case except for Item 8, Exhibits, with respect to which the Exhibit Index below is incorporated herein by reference.

------

**PART II**

**INFORMATION REQUIRED IN THE REGISTRATION STATEMENT**

**Item 8. Exhibits.**

The exhibits to this Registration Statement are listed in the Exhibit Index attached hereto and incorporated by reference herein.

---

| | | | | | |
|:---|:---|:---|:---|:---|:---|
| | | **Incorporated by Reference** | **Incorporated by Reference** | **Incorporated by Reference** | |
|<br>**Exhibit No.** |<br>**Exhibit Description** | **Form** | **Number** | **Filing Date** |<br>**Filed Herewith** |
| 4.1 | <u>[Restated Certificate of Incorporation, as amended, as of September 1, 2022](https://www.sec.gov/Archives/edgar/data/1501697/000162828022024161/x4-ex31to8xkxcharteramen.htm)</u> | 8-K | 3.1 | 09/1/2022 |  |
| 4.2 | <u>[Certificate of Amendment to Restated Certificate of Incorporation of X4 Pharmaceuticals, Inc.](https://www.sec.gov/Archives/edgar/data/1501697/000162828025019507/ex31amendmenttotherestatec.htm)</u> | 8-K | 3.1 | 04/24/2025 |  |
| 4.3 | <u>[Amended and Restated By-laws of the Company](https://www.sec.gov/Archives/edgar/data/1501697/000119312517348213/d495338dex32.htm)</u> | 8-K | 3.2 | 11/20/2017 |  |
| 4.3 | <u>[Form of Common Stock Certificate](https://www.sec.gov/Archives/edgar/data/1501697/000119312519073465/d702482dex41.htm)</u> | 8-K | 4.1 | 03/13/2019 |  |
| 4.4 | <u>[X4 Pharmaceuticals, Inc. Amended and Restated 2019 Inducement Equity Incentive Plan](https://www.sec.gov/Archives/edgar/data/1501697/000162828023029154/ex992anr2019inducementequi.htm)</u> | S-8 | 99.2 | 08/01/2023 |  |
| 5.1 | <u>[Opinion of Gibson, Dunn & Crutcher LLP](xforex51sept2025s-8.htm)</u> |  |  |  | X |
| 23.1 | <u>[Consent of Independent Registered Public Accounting Firm](ex-231x4xsx8pwcconsentsept.htm)</u> |  |  |  | X |
| 23.2 | <u>[Consent of Gibson, Dunn & Crutcher LLP (included in Exhibit 5.1)](xforex51sept2025s-8.htm)</u> |  |  |  | X |
| 24.1 | <u>[Power of Attorney (included on the signature page to this Registration Statement)](#i49cf214f634144bc94a6c7c005e8baf3_10)</u> |  |  |  | X |
| 107.1 | <u>[Filing Fee Table](ex107calculationoffilingfe.htm)</u> |  |  |  | X |

---

------

**SIGNATURES**

Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Boston, Commonwealth of Massachusetts, on September 10, 2025.

**X4 Pharmaceuticals, Inc.**

By: <u>/s/ Adam R. Craig</u> 

Adam R. Craig, M.D., Ph.D.

*Executive Chairman*

**POWER OF ATTORNEY**

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below hereby constitutes and appoints each of Adam Raymond Craig, M.D., Ph.D. and David Kirske, and each of them acting individually, as his or her true and lawful attorneys-in-fact and agents, each with full power of substitution and resubstitution in each of them singly, for him or her and in his or her name, place and stead, and in any and all capacities, to sign any and all amendments (including post-effective amendments) to this Registration Statement, and to file the same, with all exhibits thereto and other documents in connection therewith, with the Securities and Exchange Commission, granting to the attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite or necessary to be done in or about the premises, as full to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that the attorneys-in-fact and agents or any of each of them or their substitutes may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1993, this Registration Statement has been signed by the following persons in the capacities indicated on the dates indicated.

---

| | | |
|:---|:---|:---|
| **Signature** | **Title** | **Date** |
| /s/ Adam R. Craig | Executive Chairman, Chairman of the Board of Directors (principal executive officer) | September 10, 2025 |
| Adam R. Craig, M.D., Ph.D. | Executive Chairman, Chairman of the Board of Directors (principal executive officer) | September 10, 2025 |
| /s/ David Kirske | Chief Financial Officer and Treasurer<br>(principal financial officer and principal accounting officer) | September 10, 2025 |
| David Kirske | Chief Financial Officer and Treasurer<br>(principal financial officer and principal accounting officer) | September 10, 2025 |
| /s/ Michael S. Wyzga | Lead Independent Director of the Board of Directors | September 10, 2025 |
| Michael S. Wyzga | Lead Independent Director of the Board of Directors | September 10, 2025 |
| /s/ Gary J. Bridger | Director | September 10, 2025 |
| Gary J. Bridger, Ph.D. | Director | September 10, 2025 |
| /s/ Francoise De Craecker | Director | September 10, 2025 |
| Francoise De Craecker | Director | September 10, 2025 |
| /s/ Murray W. Stewart | Director | September 10, 2025 |
| Murray W. Stewart, M.D. | Director | September 10, 2025 |

---

## Ex-Filing

**EXHIBIT 107.1**

**Calculation of Filing Fee Table** 

**FORM S-8**

(Form Type)

**X4 PHARMACEUTICAL, INC.**

(Exact Name of Registrant as Specified in its Charter)

<u>Table 1: Newly Registered</u> 

---

| | | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|:---|
| **Security Type** | **Security Class Title (1)** | **Fee Calculation Rule** | **Amount**<br>**to be**<br>**Registered (2)** | **Proposed Maximum Offering Price**<br>**Per Unit (3)** | **Maximum Aggregate**<br>**Offering Price**  | **Fee Rate** | **Amount of registration fee** |
| Equity | Common Stock, $0.001 par value per share | Rule 457(h) | 12746450 | $1.61 | $20521785 | $153.10 per $1,000,000 | $3141.89 |
| **Total Offering Amounts** | **Total Offering Amounts** | **Total Offering Amounts** | **Total Offering Amounts** |  | $20521785 |  | $3141.89 |
| **Total Fee Offsets** | **Total Fee Offsets** | **Total Fee Offsets** | **Total Fee Offsets** |  |  |  |  |
| **Net Fee Due** | **Net Fee Due** | **Net Fee Due** | **Net Fee Due** |  |  |  | $3141.89 |

---

(1) Pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the "Securities Act"), this Registration Statement on Form S-8 (this "Registration Statement") shall also cover any additional shares of common stock, par value $0.001 per share (the "Common Stock"), of X4 Pharmaceuticals, Inc. (the "Registrant") that become issuable under the X4 Pharmaceuticals, Inc. Amended and Restated 2019 Inducement Equity Incentive Plan (as amended, the "Inducement Plan").

(2) Represents 12,746,450 shares of Common Stock authorized for issuance under the Inducement Plan.

(3) Estimated solely for the purpose of calculating the registration fee in accordance with Rule 457(h) under the Securities Act. The proposed maximum offering price per share and the proposed maximum aggregate offering price are based on $1.61 per share, which is the weighted-average exercise price of the stock options under the Inducement Plan being registered.

## Exhibit 5.1

![picture1.jpg](picture1.jpg)&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**EXHIBIT 5.1**

September 10, 2025

X4 Pharmaceuticals, Inc.

61 North Beacon Street, 4<sup>th</sup> Floor

Boston, MA 02134

Re:&nbsp;&nbsp;&nbsp;&nbsp;X4 Pharmaceuticals, Inc. Registration Statement on Form S-8

Ladies and Gentlemen:

We have examined the Registration Statement on Form S-8 (the "Registration Statement") of X4 Pharmaceuticals, Inc., a Delaware corporation (the "Registrant"), to be filed with the Securities and Exchange Commission (the "Commission") pursuant to the Securities Act of 1933, as amended (the "Securities Act"), in connection with the offering by the Registrant of up to 12,746,450 shares of its common stock, par value $0.001 per share (the "Common Stock"), under the Registrant's Amended and Restated 2019 Inducement Equity Incentive Plan (as amended, the "Inducement Plan").

In arriving at the opinions expressed below, we have examined originals, or copies certified or otherwise identified to our satisfaction as being true and complete copies of the originals, of the Plan and such other documents, corporate records, certificates of officers of the Registrant and of public officials and other instruments as we have deemed necessary or advisable to enable us to render these opinions. In our examination, we have assumed, without independent investigation, the genuineness of all signatures, the legal capacity and competency of all natural persons, the authenticity of all documents submitted to us as originals and the conformity to original documents of all documents submitted to us as copies. As to any facts material to these opinions, we have relied to the extent we deemed appropriate and without independent investigation upon statements and representations of officers and other representatives of the Registrant and others. We have also assumed without independent investigation that there are no agreements or understandings between or among the Registrant and any participants in the Inducement Plan that would expand, modify or otherwise affect the terms of the Inducement Plan or the respective rights or obligations of the participants thereunder.

Based upon the foregoing examination and in reliance thereon, and subject to the assumptions stated and in reliance on statements of fact contained in the documents that we have examined, we are of the opinion that the shares of Common Stock issuable under the Inducement Plan, when issued and sold in accordance with the terms of the Inducement Plan and against payment therefor, and when the Registration Statement has become effective under the Securities Act, will be validly issued, fully paid and non-assessable.

We render no opinion herein as to matters involving the laws of any jurisdiction other than the Delaware General Corporation Law (the "DGCL"). We are not admitted to practice in the State

------

of Delaware; however, we are generally familiar with the DGCL as currently in effect and have made such inquiries as we consider necessary to render the opinions above. This opinion is limited to the effect of the current state of the law of the DGCL and the facts as they currently exist. We assume no obligation to revise or supplement this opinion in the event of future changes in such law or the interpretations thereof or such facts.

We consent to the filing of this opinion as an exhibit to the Registration Statement, and we further consent to the use of our name in the Registration Statement and the prospectus that forms a part thereof. In giving these consents, we do not thereby admit that we are within the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission promulgated thereunder.

Very truly yours,

/s/ Gibson, Dunn & Crutcher, LLP

Gibson, Dunn & Crutcher, LLP

## Exhibit 23.1

**Exhibit 23.1**

**CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM**

We hereby consent to the incorporation by reference in this Registration Statement on Form S-8 of X4 Pharmaceuticals, Inc. of our report dated March 25, 2025 relating to the financial statements, which appears in X4 Pharmaceuticals, Inc.'s Annual Report on Form 10-K for the year ended December 31, 2024.

/s/ PricewaterhouseCoopers LLP

Boston, Massachusetts

September 10, 2025

<br>