NKGen Biotech Announces FDA Clearance of Investigational New Drug Application for SNK01 NK Cell Therapy to Treat Alzheimer’s Disease

NKGen’s neurodegenerative program continues to advance with dosing in the Phase 1/2a clinical trial anticipated to commence by year-end 2023

NKGen’s SNK01 program continues to show positive progress in Alzheimer’s Disease, as demonstrated by results reported in recent poster presentations in July and October 2023 at AAIC and WCN, respectively.

SANTA ANA, Calif., October 24, 2023 — NKGen Biotech Inc. (Nasdaq: NKGN) (“NKGen” or the “Company”), a clinical-stage biotechnology company focused on the development and commercialization of innovative autologous, allogeneic, and CAR-NK natural killer cell therapeutics, today announced that the U.S. Food and Drug Administration (FDA) has cleared its investigational new drug (IND) application for SNK01 natural killer (NK) cell therapy for treatment of moderate Alzheimer’s Disease (AD). SNK01 is an autologous, non-genetically modified NK cell product that has enhanced cytotoxicity and activating receptor expression.

This approved trial of 30 patients with moderate AD will look to commence before the end of this year and the first interim data is expected in early Q3 2024.

NKGen’s SNK01 program continues to show positive progress in Alzheimer’s Disease, as demonstrated by results reported in recent poster presentations in July and October 2023 at AAIC and WCN, respectively. The Phase I, 3 + 3 dose-escalation trial, data on the use of SNK01 to treat patients with Alzheimer’s Disease demonstrated that SNK01 was well tolerated and appeared to cross the blood-brain barrier to help reduce proteins and neuroinflammation in a dose-dependent manner without any related serious adverse effects observed. No dose-limiting toxicities were reported, while positive changes in cognitive function and cerebrospinal fluid biomarkers were observed.

“This represents a pivotal milestone for our company and our neurodegenerative disease program,” said Paul Y. Song, Chief Executive Officer of NKGen Biotech.  “While most current therapeutics remain focused on the mild cognitive impairment or mild dementia population, the FDA has allowed us to focus our efforts on a more advanced population for which there is currently no approved disease-modifying therapy. We believe that the FDA’s clearance validates the potential and merit of our approach.”

Dr. Song continued, “Based on the data generated from our Phase 1 dose escalation safety trial, which will be presented at the CTAD annual conference this week, we are optimistic that our planned Phase 1/2a clinical trial may show even greater cognitive benefit and a further reduction in neuroinflammation in patients given the planned higher and prolonged dosing regimen.”

About NKGen Biotech

NKGen is a clinical-stage biotechnology company focused on the development and commercialization of innovative autologous, allogeneic, and CAR-NK natural killer cell therapeutics. NKGen is headquartered in Santa Ana, California, USA. For more information, please visit www.nkgenbiotech.com.

Forward-Looking Statements

Statements contained in this press release regarding matters that are not historical facts are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements may be identified by the use of words such as “anticipate”, “believe”, “could”, “continue”, “expect”, “estimate”, “may”, “plan”, “outlook”, “future” and “project” and other similar expressions that predict or indicate future events or trends or that are not statements of historical matters. Because such statements are subject to risks and uncertainties, many of which are outside of the Company’s control, actual results may differ materially from those expressed or implied by such forward-looking statements. Such statements include, but are not limited to, statements regarding the Company’s plans for developing SNK01, including the expected timing of announcing further results from its ongoing Phase 1 clinical trial; the Company’s plans for a Phase 1/2a clinical trial and expectations that the Phase 1/2a clinical trial may show greater cognitive benefit and further reduction in neuroinflammation; the expected trial design for the Phase 1/2a clinical trial; and potential benefits of the Company’s product candidates. Risks that contribute to the uncertain nature of the forward-looking statements include: the Company’s ability to execute its plans and strategies; risks related to performing clinical studies; the risk that initial and interim results of a clinical trial do not necessarily predict final results and that one or more of the clinical outcomes may materially change as patient enrollment continues, following more comprehensive reviews of the data, and as more patient data become available; the FDA’s clearance of the Company’s IND for its Phase 1/2a clinical trial should not be relied on as a validation of SNK01’s potential or the Company’s approach; potential delays in the commencement, enrollment and completion of clinical studies and the reporting of data therefrom; the risk that studies will not be completed as planned; and NKGen’s ability to raise additional funding to complete the development of its product candidates. These and other risks and uncertainties are described more fully under the caption “Risk Factors” and elsewhere in the Company’s filings and reports, which may be accessed for free by visiting the Securities and Exchange Commission’s website at www.sec.gov and on the Company’s website under the subheading “Investors”. Investors should take such risks into account and should not rely on forward-looking statements when making investment decisions. All forward-looking statements contained in this press release speak only as of the date on which they were made. The Company undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date on which they were made, except as required by law.

Contacts:

Internal Contact:

Denise Chua, MBA, CLS, MT (ASCP)

Vice President, Investor Relations and Corporate Communications

949-396-6830

dchua@nkgenbiotech.com

External Contacts:

Chris Calabrese

Managing Director

LifeSci Advisors, LLC

ccalabrese@lifesciadvisors.com

Kevin Gardner

Managing Director

LifeSci Advisors, LLC

kgardner@lifesciadvisors.com