BOSTON – .
SNK01, being developed by NKGen Biotech, is an autologous, nongenetically modified NK cell product that has enhanced cytotoxicity and activating receptor expression.
“When we give these enhanced natural killer cells intravenously, not only do they get into the brain, but we’ve shown, through CSF biomarker data, that they reduce both amyloid and tau proteins, dramatically reducing the neuroinflammation,” said Paul Song, MD, chief executive officer of NKGen Biotech.
“Remarkably,” in the first 6 months, 90% of patients with Alzheimer’s disease demonstrated improvement or maintained stable cognitive function, based on the Alzheimer’s Disease Composite Score (ADCOMS), suggesting that SNK01 may do more than simply slow disease progression, Dr. Song said.
The findings were presented at the 16th Clinical Trials on Alzheimer’s Disease (CTAD) conference.
Sound rationale
NK cells are an essential part of the innate immune system that can shape the adaptive response by eliminating activated (not resting) autologous CD4+ T cells. Weak or deficient NK cells have been found to correlate with various diseases, including autoimmune diseases, and emerging data suggest an autoimmune component to Alzheimer’s disease.
The phase 1 study evaluated the safety, tolerability, and exploratory efficacy of SNK01 given intravenously in escalating doses every 3 weeks (four treatments in total).
Participants included 10 patients with Alzheimer’s disease confirmed by imaging. Five had mild Alzheimer’s disease, three had moderate Alzheimer’s disease, and two had advanced Alzheimer’s disease, based on baseline Clinical Dementia Rating–Sum of Boxes (CDR-SB) scores. Median baseline CDR-SB score was 9 (range, 4-18).
Cognitive assessments included CDR-SB, Mini-Mental State Examination (MMSE), Alzheimer’s disease Assessment Scale-Cognitive Subscale (ADAS-Cog) and ADCOMS. CSF biomarker analyses were performed at baseline and at 1 and 12 weeks after the final dose (weeks 11 and 22, respectively).
NK cells were successfully activated and expanded in all 10 patients and no treatment-related adverse events were observed.
Based on the CSF biomarker data, SNK01 crossed the blood–brain barrier and reduced CSF amyloid-beta 42/40 and pTau181 levels and neuroinflammation, as measured by glial fibrillary acid protein (GFAP), and the effects appeared to persist 12 weeks after the final dose.
The exploratory efficacy data show that, 1 week after final dose (week 11), compared with baseline, 30% of patients showed clinical improvement on the composite ADCOMS and 60% had a stable ADCOMS score; 50%-70% of patients were stable or improved on the CDR-SB, ADAS-Cog and/or MMSE.
“One patient went from a MMSE score of 14, which is moderate dementia, to 22, which is mild cognitive impairment,” said Dr. Song.
At 12 weeks after the final dose (week 22), 44%-89% of patients remained stable or improved in all cognitive scores compared with week 11; and 50% of the patients with stable ADCOMS scores at week 11 remained stable.
Based on the positive phase 1 data, the Food and Drug Administration has approved a phase 1/2a study in patients with moderate Alzheimer’s disease. “The trial will use a much higher dose and a prolonged dosing regimen and we think we’ll see even more dramatic results with more sustained higher dosing,” Dr. Song said.
Down the road, it will be interesting to see how NK cell therapy could “complement” anti-amyloid and anti-tau therapies, he added.