Summary Background Davunetide (AL-108, NAP) is an eightamino acid peptide that promotes microtubule stability and decreases tau phosphorylation in pre-clinical studies. Since PSP is tightly linked to tau pathology, davunetide could be an effective treatment for PSP.The goals of this study were to evaluate the efficacy and safety of davunetide in PSP. Methods A phase 2/3 double-blind, parallel group, clinical trial of davunetide 30 mg or placebo (randomized 1:1) administered intranasally twice daily for 52 weeks was conducted at 48centers. Participants met modifiedNNIPPS criteria for possible or probable PSP. Co-primary endpointswere the change from baseline in PSP Rating Scale (PSPRS) and Schwab and England ADL(SEADL) scale at up to 52 weeks. Data from all individuals who received at least one dose of medication and had a post-baseline efficacy assessment were compared using a rank-based method.Secondary outcomes included the Clinical Global Impression of Change (CGIC) and the change in regional brain volumeon MRI. Clinicaltrials.gov identifier: NCT01110720. Findings 360 participants were screened, 313 were randomized and 243 (77.6%) completed the study. There were no group differences in PSPRS (mean difference: 0.49 [95% CI: −1.5, 2.5], p = 0.72) or SEADL (1% [−2, 4%], p = 0.76) change from baseline (CFB) and mean 52 week CFB PSPRS scores were similar between the davunetide (11.3 [9.8,12.8]) and placebo groups (10.9 [9.1, 13.0]). There wereno differences in any of the secondary or exploratory endpoints. There were 11deaths in the davunetide group and tenin the placebo group. There were more nasal adverse events in the davunetide group. Interpretation Davunetide is well tolerated but is not an effective treatment for PSP. Clinical trials of disease modifying therapy are feasible in PSP and should be pursued with other promising tau-directed therapies. Funding Allon Therapeutics

Activity-dependent neuroprotective protein (ADNP) is essential for brain formation. Peptide activity scanning identified NAP (NAPVSIPQ) as a small active fragment of ADNP that provides neuroprotection at very low concentrations. In cell culture, NAP has demonstrated protection against toxicity associated with the beta-amyloid peptide, N-methyl-D-aspartate, electrical blockade, the envelope protein of the AIDS virus, dopamine, H 2 O 2 , nutrient starvation and zinc overload. NAP has also provided neuroprotection in animal models of apolipoprotein E deficiency, cholinergic toxicity, closed head injury, stroke, middle aged anxiety and cognitive dysfunction. NAP binds to tubulin and facilitates microtubule assembly leading to enhanced cellular survival that is associated with fundamental cytoskeletal elements. A liquid-chromatography, mass spectrometry assay demonstrated that NAP reaches the brain after either intravenous or intranasal administration. In a battery of toxicological tests including repeated dose toxicity in rats and dogs, cardiopulmonary tests in dogs, and functional behavioral assays in rats, no adverse side effects were observed with NAP concentrations that were~500-fold higher than the biologi- 353CNS Drug Reviews Vol. 11, No. 4, pp. 353-368 © 2005

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Abnormal accumulation of α-synuclein is associated with several neurodegenerative disorders (synucleinopathies), including sporadic Parkinson's disease (PD). Genetic mutations and multiplication of α-synuclein cause familial forms of PD and polymorphisms in the α-synuclein gene are associated with PD risk. Overexpression of α-synuclein can impair essential functions within the cell such as microtubule-dependent transport, suggesting that compounds that act on the microtubule system may have therapeutic benefit for synucleinopathies. In this study, mice overexpressing human wildtype α-synuclein under the Thy1 promoter (Thy1-aSyn) and littermate wildtype control mice were administered daily the microtubule-interacting peptide NAPVSIPQ (NAP; also known as davunetide or AL-108) intranasally for two months starting at one month of age, in a regimen known to produce effective concentrations of the peptide in mouse brain. Motor performance, coordination, and activity were assessed at the end of treatment. Olfactory function, which is altered in PD, was measured one month later. Mice were sacrificed at 4.5 months of age, and their brains examined for proteinase K-resistant α-synuclein inclusions in the substantia nigra and olfactory bulb. NAP-treated Thy1-aSyn mice showed a 38% decrease in the number of errors per step in the challenging beam traversal test and a reduction in proteinase K-resistant α-synuclein inclusions in the substantia nigra compared to vehicle treated transgenics. The data indicate a significant behavioral benefit and a long lasting improvement of α-synuclein pathology following administration of a short term (2 month) NAP administration in a mouse model of synucleinopathy.

Background/Aims: AL-108-211 was a placebo-controlled, ascending-dose study that explored the safety, tolerability and efficacy of 12 weeks of treatment with AL-108 in subjects with amnestic mild cognitive impairment. Methods: A total of 144 subjects were randomized in a 2:1 drug:placebo ratio. Subjects were enrolled into the low-dose group or placebo and then to the high-dose group or placebo. Pooling of the placebo groups yielded 3 groups (approx. 48/group) whose baseline demographics and disease characteristics were well matched. Results: AL-108 was generally safe and well tolerated. Analyses of efficacy data failed to detect a statistically significant difference between the treatment groups on the composite cognitive memory score. Analyses of the individual cognitive tasks identified signals of potential efficacy in 2 tests of memory and attention. Conclusion: These data suggest that AL-108 was generally safe, well tolerated and merits additional investigation as a treatment for Alzheimer's disease.