• In vitro studies with SNK01 have shown a direct ability to phagocytose and digest amyloid and alpha-synuclein proteins while also secreting immunoregulatory cytokines and identifying and eliminating autoreactive T cells that contribute to neuroinflammation.
  
• SNK01 autologous NK cell therapy demonstrated a positive effect on improving cerebral spinal fluid (“CSF”) and plasma levels of Tau, amyloid, and alpha-synuclein proteins in Alzheimer’s patients suggesting a potential larger application in the treatment of other neurodegenerative diseases associated with these proteins.
• 90% of patients enrolled in the proof-of-concept Phase 1 Alzheimer’s trial had improved or stable cognitive function at week 11 using the composite ADCOMS score.
• SNK01 was also found to reduce neuroinflammation, showing improved levels of Glial Fibrillary Acid Protein (GFAP) in most patients, Neurofilament-light (NfL), Growth/Differentiation Factor-15 (GDF15), and Latent Transforming Growth Factor Beta Binding Protein 2 (LTBP2), suggesting a potential preventative clinical application for SNK01.
• NKGen submitted an IND for SNK01 in Parkinson’s disease (“PD”) in Q1 2024 and anticipates to begin enrollment for its Phase 2 trial in advanced Alzheimer’s disease (“AD”) in Q2 2024.

SANTA ANA, Calif., April 25, 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 details disclosed in today’s presentation by Paul Y. Song, MD, Chairman and Chief Executive Officer of NKGen, entitled “Evaluating Adoptive Cellular Immunotherapy for Neurodegeneration with Autologous SNK01”, in which the Company shared additional information on the scientific rationale, preclinical and clinical data to date on the use of SNK01 enhanced NK cell therapy in patients with advanced AD and PD.

The presentation highlighted preclinical data showing the ability of SNK01 to phagocytose and digest both amyloid and alpha-synuclein proteins, the ability to secrete cytokines, which are able to inactivate inflammatory cells, as well as the ability to reduce autoreactive T cells, which have been implicated as a significant contributor to neuroinflammation and damage. In addition, compassionate use case studies of patients with advanced Alzheimer’s disease and Parkinson’s disease treated with SNK01 were presented as well as an update from the Company’s Phase 1 Alzheimer’s trial.

In the Phase 1 AD trial, SNK01 was administered intravenously (“IV”) every three weeks for a total of four treatments using a 3+3 dose escalation design (1, 2, and 4 x 10⁹ cells) in patients with either mild, moderate, or severe AD (Median MMSE of 14). Cognitive assessments and extensive CSF/plasma biomarker analyses were performed at baseline and at 1 and 12 weeks after the final dose. The primary endpoint was safety and secondary endpoints included changes in cognitive assessments and biomarker levels.

SNK01 was found to reduce and/or improve levels of pTau, amyloid Aβ42/40, and alpha-synuclein protein biomarkers suggesting that it could have utility far beyond Alzheimer’s. 90% of patients enrolled in the proof-of-concept Phase 1 had improved or stable cognitive function at week 11 using the composite ADCOMS score.

In the presentation, Dr. Song commented, “While elevated amyloid Aβ42/40 is primarily implicated in Alzheimer’s, alpha-synuclein protein levels have been noted in several other neurodegenerative diseases as well, including Parkinson’s, Lewy Body Dementia, Multiple System Atrophy, and Pure Autonomic Failure. In addition, elevated Tau levels have been associated with Frontotemporal Dementia, Progressive Supranuclear Palsy, and Corticobasal Degeneration. We believe the ability of SNK01 to have a positive impact on all three proteins suggests that it could have clinical utility for numerous neurodegenerative diseases well beyond just Alzheimer’s and Parkinson’s. In addition, based on the recent publication by Guo, et al.¹, which examined over 50,000 adults from the UK Biobank and found that GFAP, NfL, GDF15 and LTBP2 were consistently associated most with “incident all-cause dementia”, biobank specimens from the Phase 1 trial were reassessed to explore the effect of SNK01 on each of these biomarkers.”

Dr. Song further added, “In our dose escalation trial where the majority of the patients received suboptimal dosing and only four total treatments, we saw SNK01 was still able to reduce levels of all four biomarkers in at least 30% of all patients, suggesting that this could one day be potentially used as a safe preventative treatment for high-risk asymptomatic patients with elevated biomarkers especially with a higher dose. We are very impressed with the safety of SNK01 and ease of administration and its ability to cross the blood brain barrier. As more biomarker and clinical data emerge, we believe the potential applications of SNK01 will only increase.”

Presentation Highlights:

• SNK01 was shown to phagocytose and ingest amyloid and alpha-synuclein levels in vitro.
• SNK01 was found to produce immunoregulatory cytokines in vitro.
• SNK01 was found to reduce autoreactive T cells in vitro.
• SNK01, given via a simple IV administration, appears to cross the blood brain barrier to improve Aβ42/40, Tau, and alpha-synuclein protein levels in CSF.
• Despite a median MMSE score of 14, and 70% of patients treated at relatively low doses of SNK01, at one-week post-treatment (week 11):
  • 50–70% of all enrolled patients in the trial had either stable or improved CDR-SB, ADAS-Cog and/or MMSE scores including one patient whose MMSE score improved from 14 to 23.
  • 90% had either stable or improved ADCOMS scores.
• 60% of patients had improvements in GFAP and 30% of patients had improvements in NfL, GDF15, and LTBP2 after only four doses.
• SNK01 appears safe and well tolerated, with no treatment-related adverse events observed; and the data suggest SNK01 may have potential clinical activity in AD. A larger Phase 2 placebo-controlled AD trial with a higher dosing and longer duration will begin to enroll in Q2 2024.
• Rationale for use of SNK01 in Parkinson’s was discussed along with the clinical trial plan to initiate a Phase 1 PD trial in 2H 2024.

A copy of the presentation is available on the Scientific Publications page of the Company’s website at https://nkgenbiotech.com/.

¹Guo Y et al. Plasma proteomic profiles predict future dementia in healthy adults. Nature Aging. 2024;4:247–260. https://doi.org/10.1038/s43587-023-00565-0.

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 www.nkgenbiotech.com.

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.

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