The plasma fraction GRF6019 slows brain atrophy in mild‐to‐moderate Alzheimer’s disease

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AbstractBackgroundThe plasma fraction GRF6019 shows multiple benefits on age‐related changes in the mouse brain, including enhanced synaptic density and neurogenesis. In a trial of GRF6019 in mild‐to‐moderate Alzheimer’s disease (AD), cognition stabilized over a 24‐week period (Hannestad et al., 2020). Here we present the volumetric MRI data from that trial.MethodParticipants were 60‐90 years old with probable AD according to NIA‐AA criteria, and Mini Mental State Examination score 12‐24. They received 1 daily infusion of 100 mL or 250 mL of GRF6019 over 5 consecutive days at Week 1 and Week 13. MRIs were done at baseline at the end of the study using a MP‐RAGE or IR‐SPGR sequence. The 3D T1‐weighted scans were acquired sagittally over approximately 192 slices at a thickness of 1.0‐1.2. Images underwent the Freesurfer pipeline and hand editing to correct over‐ and under‐estimations of hippocampal volumes. Hippocampal and lateral ventricular volumes were extracted and normalized by the estimated total intracranial volume. Fold‐changes between baseline and 6 months were estimated and log2‐transformed to obtain a symmetrical distribution. MRI images from ADNI were analyzed in the same manner.ResultHippocampal volumes decreased from baseline by 2% (p<0.001, one‐sample Wilcoxon test) in ADNI AD participants (n=75), while hippocampal volumes did not significantly change in ADNI control participants (n=82; 0.03%, p>0.05) or in GRF6019‐treated AD trial participants (n=34; 0.3%, p>0.05). Lateral ventricle volumes increased from baseline by 5.2% in ADNI AD but showed smaller increases in ADNI controls (2.7%) and in GRF6019‐treated individuals (3.1%). The difference in change from baseline between GRF6019 AD and ADNI AD was significant in the right lateral ventricle (p<0.005, two‐samples Wilcoxon test) but not in the left lateral ventricle. There was no apparent difference in the change from baseline in MRI volumes between the 100 ml and 250 mL dose of GRF6019.ConclusionIn mild‐to‐moderate AD, the plasma fraction GRF6019 slowed hippocampal atrophy and lateral ventricle enlargement compared to matched individuals with AD in ADNI. The MRI data are consistent with the lack of cognitive worsening observed in these trial participants and supports continued clinical development of GRF6019 in AD.