NKGen Biotech Presented Phase I Clinical Trial Data at the 16th Annual Clinical Trials on Alzheimer’s Disease (CTAD) Conference

90% of patients demonstrated improvement or maintained stable cognitive function as per Alzheimer’s disease composite score (ADCOMS) following 11 weeks

SNK01 given intravenously (IV) appears to cross the blood-brain barrier to reduce Cerebrospinal Fluid (CSF) Aβ42/40 and pTau181 levels and neuroinflammation, as measured by Glial Fibrillary Acidic Protein (GFAP)

SANTA ANA, Calif., October 26, 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 presented a poster with Phase I trial data on the use of its investigational NK cell therapy, SNK01, to treat patients with Alzheimer’s disease (AD) at the Clinical Trials on Alzheimer’s Disease (CTAD) Annual Meeting in Boston, MA.

The poster, entitled “Treatment of Alzheimer’s Disease Subjects With Expanded Non-genetically Modified Natural Killer Cells (SNK01) With Enhanced Activity — Final Report of a Phase I Dose Escalation Study”, provided results from a single center, open label, Phase I study evaluating the safety, tolerability, and exploratory efficacy of SNK01 in patients with AD. SNK01 was given via intravenously (IV) every three weeks for a total of four treatments using a 3 + 3 dose escalation design (1, 2 & 4 x109 cells) in patients with mild, moderate or advanced AD disease confirmed by MRI and PET scans. The severity of AD was based on the baseline Clinical Dementia Rating-Sum of Boxes, or CDR-SB score.  Cognitive Assessments (CDR-SB, Mini-Mental State Examination (MMSE), The Alzheimer’s Disease Assessment Scale-Cognitive Subscale [ADAS-Cog]), composite ADCOMS score, and CSF biomarker analyses were performed at baseline and at one week and twelve weeks after the final dose (Weeks 11 and 22, respectively). The primary endpoint was safety and secondary endpoints included changes in cognitive assessments and biomarker levels.

“We are pleased to present the final data from our Phase I Alzheimer’s study further demonstrating that SNK01 is well-tolerated and appears to reduce both proteins (pTau181 and Aβ42/40) and neuroinflammation (GFAP) among trial patients,” said Paul Y. Song, M.D., CEO of NKGen Biotech. “Remarkably, despite a median baseline MMSE score of 14 and the fact that two-thirds of our patients received what we believe to be suboptimal dosing, using the ADCOMS score, 90% of patients demonstrated improvement or maintained stable cognitive function following 11 weeks, suggesting that SNK01 may do more than simply slow disease progression.”

Dr. Song continued, “When we first proposed the use of our enhanced NK cells for neurodegenerative diseases, we were met with skepticism. But, thanks to the clinical team at Hospital Angeles, who worked with us to get full Comisión Federal para la Protección contra Riesgos Sanitarios and Research Ethics Board approval, we were able to conduct this groundbreaking trial, which has provided us with invaluable clinical and biomarker data that undoubtedly helped us receive U.S. IND clearance for a Phase I/IIa study in patients with moderate stage AD. Whereas this Phase I trial was a dose escalation trial that only gave four total doses over 11 weeks, our new IND approval calls for using a higher dose and a prolonged dosing regimen. We are very excited to begin this next phase in hopes of establishing an entirely new treatment paradigm for more advanced patients.

Highlights from the Poster Presentation:

  • AD patients (n=10) from the first three cohorts in the dose escalation were analyzed (5 patients had mild AD, 3 patients had moderate AD, and 2 patients had severe AD) with a median baseline CDR-SB score of 9 (4–18).
  • NK cells were activated and expanded for all patients in the trial.
  • No treatment related adverse events were observed.
  • One week after final dose (Week 11):
    • 30% of patients showed clinical improvement on the composite ADCOMS score compared to baseline;
    • 60% of patients showed a stable ADCOMS score compared to baseline;
    • 50–70% of patients were stable or improved on the CDR-SB, ADAS-Cog and/or MMSE scores; and,
    • One patient’s score showed a switch from a moderate classification on the ADCOMS to a mild classification.
  • Twelve weeks after final dose (Week 22)*:
    • 44–89% of patients remained stable or improved in all cognitive scores compared to Week 11; and,
    • 50% of the patients with stable ADCOMS scores at Week 11 remained stable.
  • Based on the CSF biomarker data, SNK01 given via IV appears to cross the blood-brain barrier to reduce CSF pTau181 levels and neuroinflammation, as measured by GFAP; this effect appears to be persistent at Week 22.

*Data at Week 22 was only obtained for nine of the ten patients.

Please visit our website at https://nkgenbiotech.com/scientific-publications/ to view a copy of the poster.

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 (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 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 a Phase I/IIa clinical trial and expectations that the Phase I/IIa clinical trial may show greater cognitive benefit; the expected trial design for the Phase I/IIa 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, as more patient data become available, and as further clinical trials are conducted; the FDA’s clearance of the Company’s IND for its Phase I/IIa 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 the Company’s assumptions about the benefits of SNK01 may prove to be false, including the assumption that SNK01 reduces CSF pTau181 levels and neuroinflammation; 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.


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