SNK01, a cryopreserved autologous non-genetically modified NK cell product, is able to effectively reduce α-synuclein (α-syn) protein levels in the cerebral spinal fluid (CSF) of Alzheimer's patients; an important finding since increased α-syn has been correlated with worse cognitive performance and is not a target for any currently approved Alzheimer's treatments

SNK01 treatment appears to stabilize or improve cognitive function and reduce α-synuclein levels in CSF in addition to improving previously reported amyloid, tau, and neuroinflammatory markers (GFAP, NfL, YKL-40) in the majority of patients

SANTA ANA, Calif., July 30, 2024 (GLOBE NEWSWIRE) -- 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 ("NK") cell therapeutics, today announced the presentation of a poster entitled, "Subjects treated with expanded non-genetically modified autologous Natural Killer cells (SNK01) show improved changes in CSF α-synuclein and in cognitive function." SNK01 is a first-in-kind, autologous non-genetically modified NK cell product with significantly increased cytotoxicity and over 90% activating receptor expression that can be consistently produced from any donor. Clinical trial data on the effect of SNK01 α-synuclein and cognitive assessments in patients with Alzheimer's Disease ("AD") was presented at the 2024 Alzheimer's Association International Conference ("AAIC") held in Philadelphia, PA on July 30, 2024.

Elevated levels of α-syn in the CSF have been linked to cognitive impairment in AD patients and correlate with worse cognitive performance (Twohig and Nielson, 2019). NKGen's in vitro data demonstrated that SNK01 had, similarly to microglial (HMC3) cells, the ability to internalize and degrade α-syn aggregates which further supports the rationale for its use for α-synucleinopathies. Following an initial Phase I biomarker analysis that showed SNK01 could improve CSF levels of amyloid, tau, and neuroinflammation (GFAP, YKL-40, NfL), a secondary analysis was performed looking at the effect of SNK01 specifically on α-syn protein levels in CSF. Despite 70% of patients in this trial being treated with relatively low doses of SNK01, 60% had a reduction in their CSF levels of α-synuclein. In addition, 90% of patients (median MMSE score of 14 at baseline) showed stable or improved cognitive function at 11 weeks using the ADCOMS score.

"The additional data from our Phase I Alzheimer's trial shows that SNK01 has the ability to reduce CSF α-synuclein levels in Alzheimer's patients, which is important because studies have shown that high levels of α-syn are correlated with disease progression and worsened cognitive function in AD," said Dr. Paul Y. Song, MD, Chairman and CEO of NKGen. "To our knowledge, there is no treatment for Alzheimer's disease on the market that currently targets this protein as well as amyloid and tau while also reducing neuroinflammation like SNK01 does. We are excited that this additional data appears to show that treatment with SNK01 can also target, and reduce, α-syn while improving cognitive function in Alzheimer's patients. We are working diligently to expand our investigation of SNK01 in a larger Phase II trial with higher doses and a longer treatment duration. We are also looking to expand the use of SNK01 for other synucleinopathy-related neurodegenerative diseases."

Data Highlights from the Poster Presentation:

• Our in vitro studies have shown that SNK01 is able to effectively internalize and degrade α-synuclein aggregates.
• Despite 70% of subjects being treated at relatively low doses of SNK01:
  • 90% of all evaluable subjects had either stable or improved (±0.1) composite ADCOMS scores at week 11 (one-week after the final dose).
  • 60% of subjects (6/10) had a decrease in CSF α-syn compared to baseline values.
  • At Week 11, the decreases in α-syn corresponded to stable/decrease in ADCOMS in 5/6 subjects and where data was available, the α-syn levels continued below baseline through Week 22. One additional subject had a decrease in CSF α-syn compared to baseline values at Week 22.
• No treatment related adverse events were observed. SNK01 is well-tolerated by AD subjects with no dose-limiting toxicities observed at all doses tested.
• SNK01 appears to stabilize or improve cognitive function in the majority of subjects, despite 70% of subjects being treated at relatively low doses.
• SNK01 appears to reduce α-synuclein levels in CSF.
• We hypothesize that SNK01 is safe, can cross the blood brain barrier (BBB) and can impact both cognition and protein aggregates in Alzheimer's patients.
• This data warrants further investigation in a larger Phase Il trial with higher doses and a longer treatment duration.

A copy of the poster is available on the Scientific Publications page of the Company's website at . Previously disclosed Phase I data on the positive effects of SNK01 on amyloid, tau, and neuroinflammation biomarkers in Alzheimer's patients, which may not be included in this poster presentation, can also be found on the Scientific Publications webpage.

About SNK01

SNK01 is a novel cell-based, patient specific ex vivo expanded autologous natural killer cell, immunotherapeutic drug candidate. NKGen Biotech, Inc. is developing SNK01 for the treatment of neurodegenerative disorders and a broad range of cancers.

About NKGen Biotech

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

Forward-Looking Statements

Statements contained in this press release may contain "forward-looking statements" within the meaning of Section 27A of the Securities Act and Section 21E of the Securities Exchange Act of 1934, as amended. 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 and expected timing for developing SNK01, including the expected timing of completing and announcing further results from its ongoing clinical studies; and the Company's expected timing for developing its product candidates and potential benefits of its 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 study 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; 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; the risk that the abstract will not be published as planned including delays in timing, format, or accessibility; 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—Financial and Filings". 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.

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