Amyloid beta (Aβ) oligomers are thought to play an important role during development and progression of Alzheimer's disease (AD). Previously, we determined the Aβ oligomer concentrations in various AD mouse models and in human brain tissues of former AD patients. Here, we investigate which proteins are part of these Aβ oligomers, apart from Aβ itself. Because several oligomer-associated proteins have been implicated in mechanisms leading to AD pathology, identification of the Aβ oligomer proteome may provide insights into the formation of Aβ oligomers in vivo and may reveal novel targets for disease-modifying therapeutic approaches. Here, we separated different native Aβ assemblies in brain homogenates of transgenic (tg) AD mice and human AD post mortem samples by density gradient centrifugation, then isolated Aβ-containing assemblies by co-immunoprecipitation. Mass spectrometry of immunoprecipitated proteins with label-free quantification (LFQ) showed significant changes between the proteomes of Aβ oligomers from tg AD mice and wildtype (wt) mice, confirming some proteins that have been expected to bind Aβ species, like ApoE and Clusterin, but also indicating novel, so far unknown, protein content of Aβ oligomers, such as the RabGAP Tbc1d10b. Some of the hereby identified proteins, like, for example, Clusterin, were also found to be enriched in Aβ oligomers from human AD brain tissue derived homogenates as compared to brain tissue from non-demented controls (NC). Others, such as Netrin-1, were specifically enriched in Aβ oligomers in AD compared to NC samples, but not in mouse samples.

Chikungunya virus (CHIKV) is an emerging arbovirus whose replication relies on the multifunctional nonstructural protein 2 (nsP2), particularly its viral protease (nsP2pro), which is essential for polyprotein processing. In this study, we investigated how interactions with nucleic acids influence nsP2pro activity. Using High-Throughput Sequencing-Fluorescent Ligand Interaction Profiling (HiTS-FLIP), we identified specific single-stranded DNA aptamers that enhanced nsP2pro activity. Additionally, both random single-stranded DNA and single-stranded RNA were found to stimulate protease activity, whereas double-stranded DNA showed no such effect. Circular dichroism spectroscopy and secondary structure predictions confirmed that the identified aptamers adopt stable folded conformations. Similarly, structured RNA sequences were also capable of promoting protease activity. The observed stimulatory effect depended on the nucleic acid strand type, length, and buffer conditions, suggesting the involvement of electrostatic interactions. NMR experiments demonstrated that nsP2pro interacts with single-stranded DNA, accompanied by changes in its conformational dynamics upon binding. Molecular dynamic simulations of nsP2pro-RNA and -DNA complexes revealed that these nucleic acids interact specifically with the nsP2pro methyltransferase domain and induce an opening process in the protease active site. Our findings provide novel insights into the regulation of nsP2pro, enhancing our understanding of CHIKV replication mechanisms, and may guide future antiviral development strategies.

Divalent zinc ions (Zn) interact with amyloid β (Aβ) peptides and influence its Alzheimer disease (AD)-related aggregation. Little is known about the structural properties of Zn-induced Aβ oligomers. Here, we report recombinant production of fluorinated Aβ40 at Phe4, Tyr10, Phe19 and Phe20 residues and utilize these fluorinated residues as proxies to interrogate Zn-induced Aβ40 oligomers. Our NMR and CW EPR results confirm Zn binding to the N-terminal region of Aβ40 and demonstrate the reversible oligomerization and irreversible aggregation of Aβ40 upon Zn addition. The 19F NMR relaxation and dark-state exchange saturation transfer (DEST) data provide dynamical information on free Aβ40 and demonstrate that monomeric Aβ40 is in exchange with small Zn-induced Aβ40 oligomers with less than about 60 kDa molecular weight on a millisecond timescale. The 19F ENDOR data suggest that the distance between the N-terminally attached nitroxide spin and fluorinated residues within the Zn-Aβ40 aggregates is larger than about 1.5 nm. Our results shed light on the properties of soluble Zn-induced Aβ oligomers and pave the way for further structural characterization of these Aβ aggregates.

Climate change has facilitated the spread of arboviruses like the Chikungunya virus (CHIKV). CHIKV, a re-emerging virus from the Togaviridae family, has caused numerous global outbreaks. The absence of antiviral therapy against CHIKV poses a significant threat to public health. The cleavage of the viral polyprotein relies on the catalytic activity of nsP2, crucial for viral replication. Therefore the nsP2 protease presents a promising target for antiviral drug development. Animal venom-derived peptides demonstrated potential in combating various diseases including infections, cancer, and neurodegenerative disorders. In this study, we assessed the inhibitory effects of pantinin-1, a peptide derived from the scorpion Pandinus imperator with broad antimicrobial activity, against CHIKV nsP2 protease. Pantinin-1 effectively inhibited CHIKV nsP2 protease, with a half-maximal inhibitory concentration (IC₅₀) of 6.4 ± 2.04 µM and complete inhibition at 175 µM. Further examination revealed that pantinin-1 functions as a competitive inhibitor with low micromolar affinity and exhibited no toxicity up to 20 µM in cell culture. Using docking and molecular dynamics simulations, the protein-peptide interaction was analyzed, and the key residues involved in the protease binding were predicted. These findings underscore the potential of pantinin-1 as a lead candidate targeting nsP2 protease.

BACKGROUND:Amyloid transthyretin cardiomyopathy (ATTR-CM) results from extracellular deposition of misfolded transthyretin (TTR), causing progressive heart failure. Naturally-occurring antibodies (nAbs) targeting misfolded proteins exist in neurodegenerative disease, but their presence in ATTR-CM is unknown. The objective of this study is to determine whether nAbs against TTR (nAbsTTR) exist in humans and whether they are influenced by disease or its treatment. METHODS:Serum from healthy donors, umbilical cord blood (UCB), and patients with ATTR-CM - both untreated and receiving TTR-stabilizing therapy - was analyzed for nAbsTTR using immunoassays, blotting, and binding studies. Functional activity was evaluated in a fibril formation assay. RESULTS:nAbsTTR binding both native and amyloid TTR (ATTR) with high affinity (KD 30 nM/7 nM) were detected in healthy serum and UCB. NAbsTTR levels were significantly altered in ATTR-CM compared to controls: nAbsTTR (IgG) were higher while nAbsTTR (IgM) were lower. nAbsTTR of both subtypes significantly increased by 22% (p ≤ 0.05) in patients receiving TTR-stabilizing therapy. In vitro, nAbsTTR suppressed TTR fibril aggregation. CONCLUSIONS:Naturally-occurring TTR-targeting antibodies are present from birth, modulated by disease and therapy, and inhibit fibril formation. These findings reveal an unrecognized immune mechanism with potential relevance for ATTR-CM pathogenesis and treatment.

The LC3/GABARAP protein family is a promising target for selective inhibition of autophagy. Further, LC3/GABARAP ligands have been used as targeted degraders of soluble proteins, protein aggregates, mitochondria, lipid droplets, and RNA. However, the small molecules used for such applications have poor binding affinity and known off-target effects. LC3/GABARAP proteins are challenging targets for small-molecule drug development due to their long, shallow binding grooves. In this work, we evaluate multiple approaches to stabilizing the extended structure of the native binding motif, producing N-methylated peptides and stapled peptides with low nanomolar affinity. A crystal structure and molecular dynamics simulations support a model where the N-methylation pre-organizes the motif into an extended, strand-like structure. N-Methylation allowed minimization of the binding motif to a tetrapeptide that retained sub-micromolar affinity while minimizing charge and overall molecular weight. The truncated, N-methylated tetrapeptide showed passive permeability in artificial membrane and cell-based transwell assays. These results highlight new drug-like space for LC3/GABARAP ligands with high affinity and subfamily selectivity.

We present Ultra-Content Screening (UCS), a novel, scalable method combining cyclic immunostaining with high-dimensional image-based single-cell proteomics. UCS utilizes fluorescein isothiocyanate-conjugated antibodies and iterative staining-photobleaching cycles to analyze up to 40 markers in up to 100,000 peripheral blood mononuclear cells per experiment. Through precise image registration, nuclear segmentation, signal harmonization, and normalization, UCS ensures the robust tracking of individual cells across all staining cycles. Data analysis via SPADE trees allows qualitative evaluation of expression patterns and cellular phenotypes. Application to samples from acute myeloid leukemia patients demonstrates UCS potential to uncover disease-specific expression profiles and immune subpopulations. The method provides unprecedented depth in single-cell proteomic analysis of blood samples, offering valuable insights for diagnostics, personalized medicine, and therapeutic approaches. ### Competing Interest Statement The authors have declared no competing interest. Helmholtz Imaging Platform HIP

The all-d-enantiomeric-peptide RD2 was developed for the treatment of Alzheimer's disease. This study aimed to develop a specific and highly sensitive liquid chromatography-mass-spectrometric (UHPLC-ESI-QTOF) method for quantifying RD2 in the mouse brain and to validate it according to the ICH M10 guideline to investigate the pharmacokinetic profile of RD2 in its target organ. Sample preparation, chromatographic separation and quantification were very challenging due to RD2's highly hydrophilic properties, the complex matrix and the required lower limit of quantification (LLOQ). Chromatographic separation was performed on an Acquity UPLC BEH C18 column (2.1 & times; 100 mm, 1.7 mu m particle size) within 5 min at 50 degrees C with a flow rate of 0.5 mL & centerdot;min(-1). Mobile phases consisted of water and acetonitrile with 0.2% formic acid and 0.015% heptafluorobutyric acid. Ions were generated by electrospray ionization in the positive mode, and RD2 was quantified by QTOF-MS. The developed extraction method revealed complete recovery. The linearity of the calibration curve was in the range of 2 ng & centerdot;mL(-1) to 500 ng & centerdot;mL(-1) (R-2 > 0.99) with a LLOQ of 5 ng & centerdot;mL(-1). The intraday and interday accuracy and precision ranged from 0.4% to 12.2% and from 1.0% to 12.0%. RD2 remained stable in the freshly homogenized brain even after several freeze-thaw cycles, but stability decreased over time during long-term storage at -80 degrees C. Using this validated method, RD2-spiked brain homogenate samples and samples of a pharmacokinetic study with RD2 in mice were analyzed.

The d-enantiomeric peptide RD2 (named Contraloid or PRI-002 in clinical trials) was developed for the direct disassembly of toxic amyloid-β (Aβ) oligomers, which are the most neurotoxic aggregate species and play a key role in the development and progression of Alzheimer´s disease (AD). PRI-002/RD2 already demonstrated its safety and tolerability in three phase I clinical trials in young healthy volunteers and patients with mild neurocognitive impairment (MCI) or mild dementia due to AD. Results from a phase II clinical trial with PRI-002/RD2 are expected this year, which was designed to demonstrate safety and efficacy of PRI-002/RD2 in patients at an early stage of AD.The objective of this study was to evaluate the effect of age, sex, genotype and food on the pharmacokinetics of intravenous or orally administered RD2 in male and female transgenic APPswe/PS1ΔE9 (APP PS1) (n=62) or wild type (wt) mice (n=169) under fed and fasted conditions. Age and concomitant food intake influenced the pharmacokinetics of RD2. Slightly higher plasma and brain levels were observed in young compared to old wt mice. However, the effect of food on plasma levels depended on the RD2 dose administered. While at lower doses (200 mg/kg) the effect was substantial, plasma levels were 15 times higher in fasted than in non-fasted animals, the effect was only minor at higher RD2 doses (600 mg/kg).The results of this study indicate the important influence of prior food intake on the bioavailability of the compound, which may also apply to patients and is therefore of interest in further clinical development.

Introduction:Glutamate represents the dominant neurotransmitter that conveys the light information to the brain, including the suprachiasmatic nucleus (SCN), the central pacemaker for the circadian system. The neuronal and astrocytic glutamate transporters are crucial for maintaining efficient glutamatergic signaling. In the SCN, glutamatergic nerve terminals from the retina terminate on vasoactive intestinal polypeptide (VIP) neurons, which are essential for circadian functions. To date, little is known about the role of the core circadian clock gene, Bmal1, in glutamatergic neurotransmission of light signal to various brain regions. Methods:The aim of this study was to further elucidate the role of Bmal1 in glutamatergic neurotransmission from the retina to the SCN. We therefore examined the spontaneous rhythmic locomotor activity, neuronal and glial glutamate transporters, as well as the ultrastructure of the synapse between the retinal ganglion cells (RGCs) and the SCN in adult male Bmal1-/- mice. Results:We found that the deletion of Bmal1 affects the light-mediated behavior in mice, decreases the retinal thickness and affects the vesicular glutamate transporters (vGLUT1, 2) in the retina. Within the SCN, the immunoreaction of vGLUT1, 2, glial glutamate transporters (GLAST) and VIP was decreased while the glutamate concentration was elevated. At the ultrastructure level, the presynaptic terminals were enlarged and the distance between the synaptic vesicles and the synaptic cleft was increased, indicative of a decrease in the readily releasable pool at the excitatory synapses in Bmal1-/-. Conclusion:Our data suggests that Bmal1 deletion affects the glutamate transmission in the retina and the SCN and affects the behavioral responses to light.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by α-synuclein aggregation in neurons. Recent advances suggest α-synuclein aggregates could serve as a biomarker for PD and related synucleinopathies. This study used surface-based fluorescence intensity distribution analysis (sFIDA) to measure α-synuclein aggregates in urine. Patients with PD and isolated rapid eye movement sleep behavior disorder, a precursor to PD, had elevated concentrations compared with healthy controls. Sensitivity and specificity were 83% and 65% for PD versus controls and 89% and 62% for isolated rapid eye movement sleep behavior disorder versus controls. The findings highlight sFIDA's potential for diagnosing synucleinopathies. ANN NEUROL 2025;98:147-151.

Hydrogen bonds play crucial roles in functional biomolecular dynamics. It is suggested that non-conventional hydrogen bonds engaging π electrons are prevalent in proteins. The experimental support for their existence is however limited. Here, we provide direct NMR spectroscopic evidence for the existence of an NH-π interaction in an intrinsically disordered peptide (E22G-Aβ40). In particular, we demonstrate the correlation between the amide proton of a glycine residue (Gly22) and the aromatic carbons of its preceding Phe20 through π hydrogen bond-mediated scalar coupling between them, as predicted by density functional theory calculations. Our results present a proof-of-principle example of NH-π interactions in an intrinsically disordered protein (IDP) and suggest the potential prevalence of π hydrogen bonds on the surface of IDPs. Direct experimental verification of NH-π interactions in folded proteins remains for future studies.

Self-replicating amyloid beta (Aβ) oligomers are described to be synaptotoxic and responsible for reduced synaptic plasticity, impaired neuronal function and thus for development and progression of Alzheimer’s disease (AD). The all-D-enantiomeric peptide PRI-002 was developed to disassemble toxic Aβ oligomers into harmless Aβ monomers, very similar to a chaperone. PRI-002 is expected to reduce neurotoxicity and to restore synaptic plasticity in early AD stages. Target engagement has been demonstrated in vitro, in vivo and ex vivo. PRI-002 has previously been shown to reverse cognition deficits in four different animal models in four different laboratories. PRI-002 has also demonstrated to be safe and well tolerable in healthy volunteers. Here we aim to demonstrate safety in patients with mild cognitive impairment (MCI) and mild dementia due to AD and to explore efficacy. We carried out a randomized, placebo-controlled, double-blind, Phase 1b study to evaluate safety, tolerability and pharmacodynamics of PRI-002 in 20 patients with MCI to mild dementia due to AD. Eligible patients were blindly randomly assigned (1:1) to receive 300 mg PRI-002 per day or placebo for 28 days. Follow-up assessment took place on day 56. The trial is registered in EudraCT 2020-003416-27. 19 out of 20 patients were randomly assigned to PRI-002 (n=9) or placebo (n=10) and completed the study per protocol. PRI-002 was well tolerated. No SAEs were reported. Clinically meaningful findings were not reported. ECG, EEG and MRI revealed no changes. As expected, no ARIA were observed. No significant changes were detected in p-tau, t-tau, Aβ 1-40, Aβ 1-42 and Aβ oligomers in CSF. In contrast to patients in the placebo group, each of the patients in the verum group had increased short-term-memory abilities as demonstrated in the CERAD word list at day 56 vs. baseline (p<0.01). PRI-002 was well tolerated. No biomarker changes have been found after 28 days of treatment. No ARIA were detected. Memory improved significantly in the verum group. The randomized, double-blind, placebo-controlled PRImus-AD phase 2 study has finished recruiting to assess safety and efficacy of PRI-002 in patients with MCI and mild dementia due to AD (EU CT# 2022-503148-41).

Chikungunya virus (CHIKV) is an emerging pathogen affecting populations worldwide, with rapidly increasing infection rates. CHIKV, an arbovirus of the alphavirus genus, is predominantly found in tropical regions and transmitted by Aedes mosquitoes. Climate change has accelerated the global spread of these vectors, leading to outbreaks in non-tropical regions, including parts of Europe. The absence of antiviral therapies and the potential for co-infections with other viruses make CHIKV a significant public health concern. CHIKV replication relies on nsP2 cysteine protease activity to cleave its viral polyprotein into functional nonstructural and structural proteins. Targeting the nsP2 protease represents a promising strategy for antiviral therapy development. In this study, phage display was used to screen a library of peptides for potential binders of the target protease. Biophysical and biochemical analyses of the identified peptides assessed their inhibitory potential. Among the six identified peptides (named as P1-P6), four demonstrated inhibitory effects on the nsP2 protease (nsP2pro). Peptide P1 exhibited the strongest inhibitory effect, with a half-maximal inhibitory concentration (IC50) of 4.6 ± 1.9 µM, and a low cytotoxicity. The secondary structure analysis through CD spectroscopy and homology modelling revealed that P1 adopts an alpha-helical conformation. Finally, molecular dynamics simulations enabled us to investigate the dynamics of the nsP2pro active site and molecular docking was employed to predict the orthosteric binding mode of P1, providing insights into protein-peptide interaction. These findings underscore the potential of peptide P1 as a lead compound for further investigation in the context of CHIKV research.

The drug candidate PRI-002 is an all-D-enantiomeric peptide and was developed to disassemble toxic Aβ oligomers into harmless Aβ monomers. It is anticipated that PRI-002 reduces neurotoxicity and restores synaptic plasticity in early stages of AD. In studies in healthy volunteers and in patients with mild cognitive impairment (MCI) and mild dementia due to AD (EudraCT 2020-003416-27) the orally administered PRI-002 has demonstrated to be safe and well tolerable. The PRImus-AD study (EU clinical trial number 2022-503148-41) is a randomized, double-blind, placebo-controlled study to assess safety and efficacy of PRI-002 in patients with MCI or mild dementia due to Alzheimer’s Disease (AD). The trial is conducted in six European counties at 40 study sites. The trial is registered at euclinicaltrials.eu/search-for-clinical-trials/?lang=en&EUCT=2022-503148-41-00 and clinicaltrials.gov/study/NCT06182085. CSF or Amyloid-PET is used to confirm AD pathology. Stratification factors are disease state (MCI or mild dementia) and APOE e4 status. Eligible patients were randomly assigned (1:1:1) to receive 300 or 600 mg PRI-002 per day or placebo following an adaptive design for 48 to 96 weeks of treatment duration. A follow-up assessment is planned 12 weeks after the end of treatment. Besides to the endpoint of primary safety objectives the efficacy will be assessed by the change from baseline to week 48 in global outcome as measured by CDR-SB. 540 patients in total were screened. Screening was accomplished three months ahead of the original schedule. A Screening Failure Rate of 42 % resulted in approx. 300 eligible patients (at the date of abstract submission) randomly assigned to 300 or 600 mg PRI-002 per day or placebo. A blinded sample size recalculation confirmed the initial calculation of subjects to be enrolled. Although PRI-002 is not expected to induce ARIAs, ARIA monitoring is closely performed for the first 90 patients until week 24. The PRIMUS-AD phase 2 study will finally enroll about 300 patients with MCI and mild dementia due to AD to assess safety and therapeutic benefit of PRI-002. Results are expected mid-2026.

Self-replicating amyloid beta (Aβ) oligomers are described to be synaptotoxic and responsible for reduced synaptic plasticity, impaired neuronal function and thus for development and progression of Alzheimer’s disease (AD). The all-D-enantiomeric peptide PRI-002 was developed to disassemble toxic Aβ oligomers into harmless Aβ monomers, very similar to a chaperone. PRI-002 is expected to reduce neurotoxicity and to restore synaptic plasticity in early AD stages. Target engagement has been demonstrated in vitro, in vivo and ex vivo. PRI-002 has previously been shown to reverse cognition deficits in four different animal models in four different laboratories. PRI-002 has also demonstrated to be safe and well tolerable in healthy volunteers. Here we aim to demonstrate safety in patients with mild cognitive impairment (MCI) and mild AD and to explore efficacy. We carried out a randomized, placebo-controlled, double-blind, Phase 1b study to evaluate safety, tolerability and pharmacodynamics of PRI-002 in 20 patients with MCI to mild dementia due to AD. Eligible patients were randomly assigned (1:1) to receive 300 mg PRI-002 per day or placebo for 28 days. Follow-up assessment took place on day 56. The trial is registered in EudraCT 2020-003416-27. 19 out of 20 patients were randomly assigned to PRI-002 (n = 9) or placebo (n = 10) and completed the study per protocol. PRI-002 was well tolerated. No SAEs were reported. No significant changes in clinical chemistry, hematology or hematoserology were detected. Clinically meaningful findings were not reported. ECG, EEG and MRI revealed no changes. As expected, no ARIA were observed. No significant changes were detected in p-tau, t-tau, Aβ 1-40, Aβ 1-42 and Aβ oligomers in CSF. In contrast to patients in the placebo group, each patient in the verum group had increased short-term-memory abilities as demonstrated in the CERAD word list at day 56 vs. baseline (p<0.01). PRI-002 was well tolerated. No biomarker changes have been found after 28 days of treatment. No ARIA were detected. Memory improved significantly in the verum group. A phase 2 study has started to assess the potential therapeutic benefit of PRI-002 in patients with mild neurocognitive impairment and mild dementia due to AD.

Climate change has enhanced the spread of arboviruses such as Chikungunya virus (CHIKV). CHIKV is a re-emerging virus from the family Togaviridae that has spread globally, causing numerous outbreaks. The lack of antiviral therapy against CHIKV makes it a significant threat to public health. Cleavage of the viral polyprotein depends on the catalytic activity of nsP2, which is essential for viral replication. Due to this critical role, the nsP2 protease is a promising target for antiviral drug development. Animal venom-derived peptides have shown great potential against a variety of diseases, including infections, cancer, and neurodegenerative disorders. In this study, we evaluated the inhibitory effects and properties of pantinin-1, a peptide derived from the scorpion Pandinus imperator with broad antimicrobial activity, against CHIKV nsP2 protease. Pantinin-1 effectively inhibited CHIKV nsP2 protease, with a half-maximal inhibitory concentration (IC50) of 6.4 ± 2.04 µM and complete inhibition at 175 µM. Further analysis revealed that pantinin-1 acts as a competitive inhibitor with low micromolar affinity and showed no toxicity up to 20 µM in cell culture. Lastly, using molecular docking with subsequent molecular dynamics, the protein–peptide interaction was analyzed, and the key residues involved in the interaction with the protease were predicted. These findings highlight the potential inhibitory effect of pantinin-1 as a lead candidate targeting nsP2 protease. ### Competing Interest Statement The authors have declared no competing interest. Jürgen Manchot Brazilian Council for Scientific and Technological Development, CNPq, 309940/2019-2, 403193/2022-2 São Paulo Research Foundation, 2024/13327-2, 2020/08615-8, 2024/01956-5

BACKGROUND:Self-replicating amyloid beta (Aβ) oligomers are described to be synaptotoxic and responsible for reduced synaptic plasticity, impaired neuronal function and thus for development and progression of Alzheimer's disease (AD). The all-D-enantiomeric peptide PRI-002 was developed to disassemble toxic Aβ oligomers into harmless Aβ monomers, very similar to a chaperone. PRI-002 is expected to reduce neurotoxicity and to restore synaptic plasticity in early AD stages. Target engagement has been demonstrated in vitro, in vivo and ex vivo. PRI-002 has previously been shown to reverse cognition deficits in four different animal models in four different laboratories. PRI-002 has also demonstrated to be safe and well tolerable in healthy volunteers. Here we aim to demonstrate safety in patients with mild cognitive impairment (MCI) and mild dementia due to AD and to explore efficacy. METHOD:We carried out a randomized, placebo-controlled, double-blind, Phase 1b study to evaluate safety, tolerability and pharmacodynamics of PRI-002 in 20 patients with MCI to mild dementia due to AD. Eligible patients were blindly randomly assigned (1:1) to receive 300 mg PRI-002 per day or placebo for 28 days. Follow-up assessment took place on day 56. The trial is registered in EudraCT 2020-003416-27. RESULT:19 out of 20 patients were randomly assigned to PRI-002 (n=9) or placebo (n=10) and completed the study per protocol. PRI-002 was well tolerated. No SAEs were reported. Clinically meaningful findings were not reported. ECG, EEG and MRI revealed no changes. As expected, no ARIA were observed. No significant changes were detected in p-tau, t-tau, Aβ 1-40, Aβ 1-42 and Aβ oligomers in CSF. In contrast to patients in the placebo group, each of the patients in the verum group had increased short-term-memory abilities as demonstrated in the CERAD word list at day 56 vs. baseline (p<0.01). CONCLUSION:PRI-002 was well tolerated. No biomarker changes have been found after 28 days of treatment. No ARIA were detected. Memory improved significantly in the verum group. The randomized, double-blind, placebo-controlled PRImus-AD phase 2 study has finished recruiting to assess safety and efficacy of PRI-002 in patients with MCI and mild dementia due to AD (EU CT# 2022-503148-41).