# EDGAR Filing Document

**Accession Number:** 0001845459
**File Stem:** 0001213900-26-012879
**Filing Date:** 2026-2
**Character Count:** 12499
**Document Hash:** 42eb7649612c7405f1e0ab9665e96727
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001213900-26-012879.hdr.sgml**: 20260205

**ACCESSION NUMBER**: 0001213900-26-012879

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 14

**CONFORMED PERIOD OF REPORT**: 20260130

**ITEM INFORMATION**: Entry into a Material Definitive Agreement

**ITEM INFORMATION**: Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20260205

**DATE AS OF CHANGE**: 20260205

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** NKGen Biotech, Inc.
- **CENTRAL INDEX KEY:** 0001845459
- **STANDARD INDUSTRIAL CLASSIFICATION:** BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-40427
- **FILM NUMBER:** 26604208

**BUSINESS ADDRESS:**
- **STREET 1:** 3001 DAIMLER ST,
- **CITY:** SANTA ANA
- **STATE:** CA
- **ZIP:** 92705
- **BUSINESS PHONE:** (949) 396-6830

**MAIL ADDRESS:**
- **STREET 1:** 3001 DAIMLER ST,
- **CITY:** SANTA ANA
- **STATE:** CA
- **ZIP:** 92705

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Graf Acquisition Corp. IV
- **DATE OF NAME CHANGE:** 20210210

?xml version='1.0' encoding='ASCII'?

**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION**

**Washington, D.C. 20549**

**FORM 8-K**

**CURRENT REPORT**

**Pursuant to Section 13 or 15** **(d) of the Securities Exchange Act of 1934**

**Date of Report (Date of earliest event reported): January 30, 2026**

**NKGen Biotech, Inc.**

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

---

| | | |
|:---|:---|:---|
| **Delaware** | **001-40427** | **86-2191918** |
| **(State or other jurisdiction<br> of incorporation)** | **(Commission File Number)** | **(IRS Employer <br> Identification No.)** |

---

**3001 Daimler Street**

**Santa Ana, CA, 92705**

**(Address of principal executive offices and zip code)**

**Registrant's telephone number, including area code: (949) 396-6830**

**Not Applicable**

**(Former name or former address, if changed since last report)**

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2 below):

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

**Securities registered pursuant to Section 12(b) of the Act:**

---

| | | |
|:---|:---|:---|
| &nbsp;&nbsp;**Title of each class** | &nbsp;&nbsp;**Trading Symbol(s)** | &nbsp;&nbsp;**Name of each exchange on which registered** |
| &nbsp;&nbsp;**Common Stock, $0.0001 par value per share** | &nbsp;&nbsp;**NKGN** | &nbsp;&nbsp;**OTC Expert Market** |
| &nbsp;&nbsp;**Warrants, each whole warrant exercisable for one share of Common Stock at an exercise price of $11.50 per share** | &nbsp;&nbsp;**NKGNW** | &nbsp;&nbsp;**OTC Expert Market** |

---

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

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 13(a) of the Exchange Act. ☐

**Item 1.01. Entry into a Material Definitive Agreement.**

On January 30, 2026, NKGen Biotech, Inc. (the "Company") and NKGen Operating Biotech, Inc., a Delaware corporation (together with the Company, the "Borrowers"), entered into a third amendment (the "Alpine Third Amendment") to that certain secured promissory note with AlpineBrook Capital GP I Limited, dated January 5, 2026, as amended by that certain amendment to secured promissory note dated January 12, 2026 and that certain amendment no. 2 to secured promissory note (the "Note").

The Alpine Third Amendment provides an additional $251,000 of funding to the Borrowers (the "Fourth Additional New Loan"). As a result, the principal amount of the Note was increased to $26,758,106. The Alpine Third Amendment also clarifies that interest on the Fourth Additional New Loan accrues from January 30, 2026 (the date on which the Fourth Additional New Loan was funded).

The foregoing description of the Alpine Third Amendment does not purport to be complete and is qualified in its entirety by the terms and conditions of the Alpine Third Amendment, which is filed as Exhibit 10.1 to this Current Report on Form 8-K and incorporated herein by reference.

**Item 2.03. Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.**

The disclosures set forth in Item 1.01 are incorporated by into this Item 2.03 by reference.

**Item 9.01. Financial Statements and Exhibits**

(d) Exhibits.

---

| | |
|:---|:---|
| **Exhibit No.** | **Description** |
| 10.1 | [Amendment No. 3 to Secured Promissory Note issued to the AlpineBrook Capital GP I Limited, dated January 30, 2026.](ea027535001ex10-1_nkgen.htm) |
| 104 | Cover Page Interactive Data File (embedded within the Inline XBRL document) |

---

**SIGNATURES**

Pursuant to the requirements of Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

---

| | | |
|:---|:---|:---|
|  | **NKGEN BIOTECH, INC.** | **NKGEN BIOTECH, INC.** |
| Date: February 5, 2026 | /s/ Paul Y. Song | /s/ Paul Y. Song |
|  | Name: | Paul Y. Song |
|  | Title: | Chief Executive Officer |
|  |  | *(Principal Executive Officer)* |

---

## Exhibit 10.1

**Exhibit 10.1**

**AMENDMENT NO. 3 TO SECURED PROMISSORY NOTE**

This **Amendment No. 3 to Secured Promissory Note**, dated January 30, 2026 (the "***Amendment***") is entered into by and among **NKGen Biotech, Inc.**, a Delaware corporation (the "***Company***"), **NKGen Operating Biotech, Inc.**, a Delaware corporation (the "***Company Sub***," together with the Company, the "***Borrowers***," and each, a "***Borrower***") and AlpineBrook Capital GP I Limited ("***Lender***"). Capitalized terms used in this Amendment and not otherwise defined in this Amendment have the respective meanings ascribed to them in the Note (as defined below).

**Recitals**

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**A.** Borrowers issued that certain secured promissory note (the "***Original Note***") on January 5, 2026 to Lender in the principal amount of US$25,840,106, and the parties entered into an amendment to secured promissory note on January 12, 2026 (the "***Amendment No. 1***") and another amendment no. 2 to secured promissory note on January 23, 2026 (the "***Amendment No. 2***," together with the Original Note and the Amendment No. 1, the "***Note***") to increase the principal amount of the Original Note to US$26,507,106.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**B.** Borrowers have requested Lender to extend an additional US$251,000 new loan (the "***Fourth Additional New Loan***") to Borrowers and the parties desire to amend the Note as set forth in this Amendment.

**Agreement**

In consideration of the mutual covenants and agreements set forth herein and for good and valuable consideration, the receipt and adequacy of which are hereby acknowledged, the parties hereto agree as follows:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**1. Principal Amount**. The amount corresponding to "Principal Amount of Note" at the beginning of the Note is hereby amended and restated to be "US$26,758,106."

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**2. Obligations**. For all purposes under the Note, the term "***Obligations***" shall mean all present and future obligations and liabilities (whether actual or contingent and whether owed jointly or severally or in any other capacity whatsoever) of Borrowers to Lender, under or pursuant to the Note, as amended by this Amendment.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**3. Additional New Loan**. For all purposes under the Note, the term "***Additional New Loan***" shall mean the US$300,000 extended by Lender to Borrowers on January 5, 2026, the US$295,000 extended by Lender to Borrowers in connection with Amendment No. 1 (the "***Second Additional New Loan***"), the US$372,000 extended by Lender to Borrowers in connection with Amendment No. 2 (the "***Third Additional New Loan***"), and the Fourth Additional New Loan.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**4. Interest**. Section 1(c) of the Note is hereby amended by deleting the new sentence inserted under Section 4 of the Amendment No. 2 in its entirety and replacing with the bellow:

"Interest on US$25,840,106 of the Principal Amount shall start to accrue on January 5, 2026, interest on the Second Additional New Loan shall start to accrue on January 12, 2026, interest on the Third Additional New Loan shall start to accrue on January 23, 2026, and interest on the Fourth Additional New Loan shall start to accrue when funded, expected to be on January 30, 2026."

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**5. Representations and Warranties**. Each Borrower hereby jointly and severally represents and warrants to Lender that the representations and warranties set forth under Section 5 of the Note are true and correct in all respects as of the date hereof.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**6. Effect of Amendment**. Upon the effectiveness of this Amendment, each reference in the Note to "this Note," "hereunder," "hereof," "herein," or words of like import shall mean and be a reference to the Note, as amended by this Amendment, and each reference to the Note in any other document, instrument or agreement executed or delivered in connection with the Note shall mean and be a reference to the Note, as amended by this Amendment. All other terms and conditions of the Note not specifically amended by this Amendment will be unaffected hereby and remain in full force and effect.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**7. Miscellaneous**. Section 7 (Miscellaneous Provisions) of the Note is hereby incorporated by reference and shall apply to this Amendment, *mutatis mutandis*.

[Signature Page Follows]

**In Witness Whereof**, the undersigned have caused this Amendment No. 3 to Secured Promissory Note to be executed and delivered on the date first above written.

---

| | | |
|:---|:---|:---|
| **Borrowers:** | **Borrowers:** | **Borrowers:** |
| **NKGEN BIOTECH, INC.** | **NKGEN BIOTECH, INC.** | **NKGEN BIOTECH, INC.** |
| By: | /s/ Paul Song | /s/ Paul Song |
|  | Name: | Paul Y. Song |
|  | Title: | Chief Executive Officer |
| Address: | Address: |  |
| Email: | Email: |  |
| **NKGEN OPERATING BIOTECH, INC.** | **NKGEN OPERATING BIOTECH, INC.** | **NKGEN OPERATING BIOTECH, INC.** |
| By: | /s/ Paul Song | /s/ Paul Song |
|  | Name: | Paul Y. Song |
|  | Title: | Chief Executive Officer |
| Address: | Address: |  |
| Email: | Email: |  |

---

[Signature Page to Amendment No. 3 to Secured Promissory Note]

**In Witness Whereof**, the undersigned have caused this Amendment No. 3 to Secured Promissory Note to be executed and delivered on the date first above written.

---

| | | |
|:---|:---|:---|
| **Lender:** | **Lender:** | **Lender:** |
| **ALPINEBROOK CAPITAL GP I LIMITED** | **ALPINEBROOK CAPITAL GP I LIMITED** | **ALPINEBROOK CAPITAL GP I LIMITED** |
| By: | /s/ Hanhan Xu | /s/ Hanhan Xu |
|  | Name: | Hanhan Xu |
|  | Title: | Managing Director |
| Address: | Address: |  |
| Email: | Email: |  |

---

[Signature Page to Amendment No. 3 to Secured Promissory Note]