X4 Pharmaceuticals Enters Material Definitive Agreement

TL;DR

X4 Pharma just signed a big deal, filing an 8-K for it.

AI Summary

On October 23, 2025, X4 Pharmaceuticals, Inc. entered into a material definitive agreement. The company, formerly known as Arsanis, Inc., is incorporated in Delaware and headquartered in Boston, MA. This filing is a current report under Section 13 or 15(d) of the Securities Exchange Act of 1934.

Why It Matters

This filing indicates a significant new contract or partnership for X4 Pharmaceuticals, which could impact its future operations and financial performance.

Risk Assessment

Risk Level: medium — Entering into material definitive agreements can carry inherent risks related to the terms, execution, and potential impact on the company's financial health.

Key Numbers

• 001-38295 — SEC File Number (Identifies the company's filing with the SEC)
• 27-3181608 — IRS Employer Identification No. (Company's tax identification number)

Key Players & Entities

• X4 Pharmaceuticals, Inc. (company) — Registrant
• Arsanis, Inc. (company) — Former company name
• October 23, 2025 (date) — Date of earliest event reported
• Boston, Massachusetts (location) — Principal executive offices
• Delaware (location) — State of incorporation

FAQ

Key Financial Figures

• $0.001 — ich registered Common Stock, par value $0.001 per share XFOR The Nasdaq Stock Market
• $2.90 — mon stock at a public offering price of $2.90 per share and, in lieu of common stock
• $2.899 — arrants") at a public offering price of $2.899 per share, which represents the per sha
• $145.6 m — fering are expected to be approximately $145.6 million, after deducting the Underwriters

Filing Documents

• xfor-20251023.htm (8-K) — 36KB
• ex11oct2025underwritingagr.htm (EX-1.1) — 296KB
• xforex41formofpre-fundedwa.htm (EX-4.1) — 120KB
• xfor-oct2025ex51opinion.htm (EX-5.1) — 13KB
• image_0a.jpg (GRAPHIC) — 0KB
• image_1.jpg (GRAPHIC) — 26KB
• 0001501697-25-000032.txt ( ) — 709KB
• xfor-20251023.xsd (EX-101.SCH) — 2KB
• xfor-20251023_lab.xml (EX-101.LAB) — 23KB
• xfor-20251023_pre.xml (EX-101.PRE) — 13KB
• xfor-20251023_htm.xml (XML) — 3KB

01 Entry into a Material Definitive Agreement

Item 1.01 Entry into a Material Definitive Agreement. On October 23, 2025, X4 Pharmaceuticals, Inc. (the "Company") entered into an underwriting agreement ("Underwriting Agreement") with Leerink Partners LLC, Stifel, Nicolaus & Company, Incorporated and Guggenheim Securities, LLC, as the representatives of the underwriters named therein (the "Underwriters"), to issue and sell 45,860,000 shares of the Company's common stock at a public offering price of $2.90 per share and, in lieu of common stock to certain investors, pre-funded warrants to purchase 700,000 shares of the Company's common stock (the "Pre-Funded Warrants") at a public offering price of $2.899 per share, which represents the per share public offering price for the common stock less the $0.001 per share exercise price for each Pre-Funded Warrant (the "Offering"). In addition, the Company has granted the Underwriters an option for a period of 30 days to purchase up to an additional 6,984,000 shares of its common stock at the public offering price, less the underwriting discounts and commissions, which the Underwriters exercised in full on October 24, 2025. The Pre-Funded Warrants will be exercisable at any time after the date of issuance. A holder of Pre-Funded Warrants may not exercise the warrant if the holder, together with its affiliates, would beneficially own more than 4.99% or 9.99%, as applicable, of the number of shares of common stock outstanding immediately after giving effect to such exercise. A holder of Pre-Funded Warrants may increase or decrease this percentage to a percentage not in excess of 19.99% by providing prior notice to the Company, provided that any increase will not be effective until the 61st day after such notice is delivered to the Company. The net proceeds from the Offering are expected to be approximately $145.6 million, after deducting the Underwriters' discounts and commissions and estimated offering expenses. The securities described above were offered pursuant

01 Financial Statements and Exhibits

Item 9.01 Financial Statements and Exhibits. (d) Exhibits. EXHIBIT INDEX Exhibit No. Description 1.1 Underwriting Agreement, dated as of October 23, 2025, by and among X4 Pharmaceuticals, Inc., Leerink Partners LLC, Stifel, Nicolaus & Company, Incorporated and Guggenheim Securities, LLC. 4.1 Form of Pre-Funded Warrant. 5.1 Opinion of Gibson, Dunn & Crutcher LLP . 23.1 Consent of Gibson, Dunn & Crutcher LLP (included in Exhibit 5.1). 104 Cover Page Interactive Data File (embedded within the Inline XBRL document). SIGNATURE Pursuant to the requirements of the Securities Exchange Act of 1934 the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. X4 PHARMACEUTICALS, INC. Date: October 24, 2025 By: /s/ David H. Kirske Name: David H. Kirske Title: Chief Financial Officer

View Full Filing

View this 8-K filing on SEC EDGAR