An eight-amino-acid fragment of one of the brain's most essential proteins—tested in 457 patients, failed its biggest trial, and now pivoting to the rare genetic disease it was born from

Some proteins are so essential to brain development that losing even one of two copies—a single mutation—causes devastating neurological consequences. ADNP (activity-dependent neuroprotective protein) is one of those proteins. Children with ADNP syndrome, caused by mutations in just one copy of the ADNP gene, develop intellectual disability, autism spectrum features, and motor dysfunction. ADNP is not optional equipment—it is critical infrastructure.

NAP is the shortest fragment of ADNP that retains its neuroprotective activity: eight amino acids (NAPVSIPQ) that protect neurons at femtomolar concentrations—that is, concentrations of approximately 0.000000000000001 moles per liter. The mechanism centers on microtubule stabilization: NAP binds to tubulin, strengthens the cell's internal scaffolding, and prevents the tau protein aggregation that drives neurodegenerative diseases like Alzheimer's, frontotemporal dementia, and progressive supranuclear palsy.

The clinical story is a cautionary tale about the distance between preclinical promise and therapeutic reality. NAP was tested in 457 patients across two clinical trials. The large trial (313 patients with PSP) was definitively negative. The small trial (144 patients with mild cognitive impairment) showed a positive memory signal. The compound is now being repositioned for the rare genetic disease it was derived from—ADNP syndrome—where the biological rationale is arguably stronger than for any neurodegenerative disease application.

Quick Facts: NAP at a Glance

What Is NAP (Davunetide)?

Pronunciation: NAP dav-you-NET-ide

Inside every neuron, an elaborate scaffolding system keeps the cell's shape, transports cargo from the cell body to the synaptic terminals, and provides the structural framework for axons and dendrites. This scaffolding is made of microtubules—hollow tubes assembled from a protein called tubulin. When microtubules destabilize, neurons lose their shape, cargo transport fails, and the cell begins to die. In diseases like Alzheimer's, frontotemporal dementia, and progressive supranuclear palsy, a protein called tau—which normally stabilizes microtubules—detaches, aggregates into toxic tangles, and leaves the cell's scaffolding to collapse.

NAP is an eight-amino-acid peptide designed to prevent that collapse. It is the smallest fragment of a protein called ADNP (activity-dependent neuroprotective protein) that retains the ability to stabilize microtubules and protect neurons. In lab experiments, NAP does this at femtomolar concentrations—concentrations so low that only a few hundred molecules per cell may be sufficient for protection.

NAP was discovered by Illana Gozes at Tel Aviv University, who spent decades characterizing ADNP—a protein so essential that mice lacking both copies die during embryonic development, and children with mutations in one copy develop ADNP syndrome, a severe neurodevelopmental disorder. NAP represents the active core of ADNP's neuroprotective function, distilled into a peptide small enough to deliver as a drug.

Origins and Discovery

The NAP story begins with ADNP itself. In the late 1990s, Illana Gozes' laboratory at Tel Aviv University identified ADNP as an activity-dependent protein essential for brain development. The discovery came through a systematic search for neuroprotective factors released by glial cells in response to the neuropeptide VIP (vasoactive intestinal peptide).

ADNP turned out to be far more than a neuroprotective factor. It is one of the most essential proteins in mammalian development. ADNP-null mice die during embryogenesis (around day 8.5) due to catastrophic neural tube defects. ADNP-haploinsufficient mice (one working copy) develop normally but show cognitive deficits, reduced hippocampal neurogenesis, and behavioral abnormalities. In humans, heterozygous ADNP mutations cause Helsmoortel-Van der Aa syndrome—one of the most common single-gene causes of autism spectrum disorder with intellectual disability.

NAP (NAPVSIPQ) was identified as the minimal active fragment through systematic truncation studies. This eight-amino-acid sequence, located within ADNP's neuroprotective domain, retained full neuroprotective activity at femtomolar concentrations while being small enough for intranasal or intravenous delivery.

The compound was developed pharmaceutically by Allon Therapeutics (later acquired by Paladin Labs, then merged into Endo International) as AL-108 (intranasal) and AL-208 (IV). The pivotal PSP trial represented the company's bet that microtubule stabilization could slow a tauopathy. When it failed, mainstream pharmaceutical development stalled. Coronis Neurosciences later picked up the compound specifically for ADNP syndrome—returning NAP to the genetic condition that defined its parent protein.

Mechanism of Action

Microtubule Stabilization via EB3 Interaction

NAP binds to tubulin and stabilizes microtubule dynamics by enhancing the interaction with EB3 (end-binding protein 3), a protein that tracks and stabilizes the growing plus-ends of microtubules. This is mechanistically distinct from taxane-class microtubule stabilizers (paclitaxel)—NAP promotes dynamic stability rather than rigid freezing. The result is preserved axonal transport, maintained dendritic architecture, and resistance to tau-mediated destabilization (PMID 21070973).

Tau Aggregation Inhibition

NAP competes with tau for microtubule binding sites and prevents pathological tau-tau interactions that lead to neurofibrillary tangle formation. In transgenic tauopathy mouse models, NAP treatment reduces tangle burden and preserves cognitive function. This dual action—stabilizing microtubules while preventing the tau aggregation that destabilizes them—is the basis for NAP's positioning as a tauopathy therapeutic.

Autophagy Enhancement

NAP promotes autophagy—the cellular clearance system that removes damaged proteins and organelles (PMID 28346453). Enhanced autophagy may help clear pre-existing tau aggregates and other proteopathic species. This "cleanup" mechanism complements the "prevention" mechanism of microtubule stabilization.

Femtomolar Neuroprotection

In cell culture, NAP protects neurons against oxidative stress, excitotoxicity, and growth factor deprivation at femtomolar concentrations (10⁻¹⁵ M)—among the most potent neuroprotective effects ever measured for a peptide (PMID 14502299). This extraordinary potency suggests that very small amounts of NAP may have biological significance, though whether femtomolar potency in vitro translates to clinical efficacy at achievable brain concentrations remains uncertain.

Key Research Areas and Studies

Tauopathies (PSP, Alzheimer's, FTLD)

NAP's primary therapeutic hypothesis was that microtubule stabilization could slow or halt the progression of tauopathies—diseases where tau pathology is the primary driver of neurodegeneration. The PSP trial (Boxer et al. 2014) was the definitive clinical test of this hypothesis.

Mild Cognitive Impairment

The Phase 2 MCI trial (Javitt et al. 2012) tested NAP in a population with early memory problems—before full Alzheimer's disease develops. The positive memory signal suggests NAP may be more effective in early-stage cognitive decline than in advanced neurodegeneration, though this hypothesis remains untested in a confirmatory trial.

ADNP Syndrome

The orphan drug development of CP201 (a ketone body-based NAP formulation by Coronis Neurosciences) for ADNP syndrome represents the most biologically compelling application. ADNP syndrome children have a known deficiency in ADNP protein—providing the exact peptide fragment that the mutated gene fails to produce is a logical therapeutic strategy.

Neuroprotection Broadly

Beyond tauopathies, NAP has shown neuroprotective effects in animal models of stroke, traumatic brain injury, and excitotoxic injury. These applications have not been pursued clinically.

The PSP Failure—What Negative Trials Teach Us

The Phase 2/3 PSP trial (Boxer et al. 2014, PMID 24842088) is the single most important piece of evidence in NAP's clinical story—and it was negative. Understanding what that means (and does not mean) requires looking at negative trials as information rather than failure.

What the trial tested: 313 patients with progressive supranuclear palsy received either intranasal davunetide (AL-108, 30 mg twice daily) or placebo for 52 weeks. Primary endpoints were the PSP Rating Scale and the Schwab and England Activities of Daily Living scale.

What it found: No significant difference between davunetide and placebo on either primary endpoint or on any secondary endpoint.

What it means: - NAP does not slow clinical progression of PSP at the tested dose and route over 52 weeks. - PSP may be the wrong indication—it is a relentlessly progressive tauopathy where neurons are already dying rapidly by the time symptoms appear. Microtubule stabilization may be "too late" in this disease. - The dose may have been insufficient. Intranasal delivery achieves CNS concentrations, but whether 30 mg twice daily produces femtomolar brain levels is unknown. - PSP is a notoriously difficult disease to treat—no drug has ever shown clinical benefit in PSP. The disease may simply be intractable by the time it is diagnosed.

What it does NOT mean: - It does not prove NAP is pharmacologically inactive in humans. The MCI trial showed a positive signal. - It does not invalidate the microtubule stabilization mechanism. The mechanism was not tested in a disease where it could plausibly work. - It does not mean NAP cannot help ADNP syndrome children, where the biological rationale is different (replacing a missing protein vs. slowing a disease).

Negative Phase 3 trials are data. They narrow the space of possible applications. The community should understand CASTA (Cerebrolysin in stroke) and the PSP trial (NAP in PSP) the same way: rigorous tests that gave clear answers about specific questions.

Claims vs. Evidence

We currently don’t have any vetted partners for this compound. Check back soon.

The Human Evidence Landscape

Boxer et al. (2014) — PSP Phase 2/3 Trial

Design: Double-blind, placebo-controlled, multicenter RCT. N=313 patients with probable or possible PSP. Intranasal davunetide (AL-108) 30 mg twice daily vs. placebo for 52 weeks. PMID 24842088.

Primary endpoints: PSP Rating Scale (PSPRS) and Schwab and England Activities of Daily Living (SEADL).

Result: No significant difference between davunetide and placebo on either primary endpoint. No significant differences on any secondary endpoint. The trial was adequately powered and well-conducted.

Safety: Adverse event profile similar to placebo. Nasal irritation was the most common treatment-related complaint. No serious safety signals over 52 weeks.

Significance: This is the largest, most rigorous trial of NAP and it was definitively negative. It effectively ended mainstream pharmaceutical interest in NAP for neurodegenerative diseases.

Javitt et al. (2012) — MCI Phase 2 Trial

Design: Randomized, double-blind, placebo-controlled. N=144 patients with amnestic mild cognitive impairment. Intranasal AL-108 (5 mg or 30 mg daily) vs. placebo for 12 weeks. PMID 23028944.

Result: Positive signal on memory composite scores. The 30 mg dose showed improvement on delayed recall and composite memory measures.

Significance: This positive result suggests NAP may have cognitive benefits in early-stage memory decline—before the neurodegeneration becomes too severe. However, the positive MCI Phase 2 was never advanced to Phase 3, and the subsequent PSP failure shifted the company's strategy.

ADNP Syndrome — CP201 (Pending)

Coronis Neurosciences is developing CP201 for ADNP syndrome. Early clinical data is pending. This represents NAP's most biologically rational application—providing the neuroprotective fragment of a protein that ADNP syndrome patients cannot produce in sufficient quantities.

Safety, Risks, and Limitations

Favorable Safety Profile from Clinical Trials

The PSP trial (N=313, 52 weeks) provides unusually robust safety data for a peptide. Adverse events were similar to placebo. No immunogenicity, hepatotoxicity, or cardiovascular concerns were identified. The MCI trial (N=144, 12 weeks) was similarly well-tolerated.

Nasal Irritation

The most common treatment-related side effect across both trials. Mild and transient.

No Serious Safety Signals

No drug-related serious adverse events were reported in either trial. This is meaningful: the PSP trial's 52-week duration means NAP has a year's worth of controlled safety data in a patient population.

Limited Long-Term Data Beyond One Year

While 52 weeks of controlled data is substantial for a peptide, longer-term safety is unknown.

Stability Concerns

NAP is an octapeptide with a relatively short plasma half-life (~15-20 minutes IV). Intranasal delivery bypasses first-pass metabolism but the duration of CNS exposure at any given dose is uncertain.

Legal and Regulatory Status

United States: Not approved. Orphan drug designation for ADNP syndrome (CP201, Coronis Neurosciences). Phase 2/3 PSP trial completed (failed). Phase 2 MCI trial completed (positive signal, not advanced).

No country approvals: Unlike Semax or Selank, NAP has not achieved regulatory approval anywhere.

Legal status: Research chemical. Available from peptide vendors. The CP201 formulation (Coronis Neurosciences) is investigational.

Research Protocols and Formulation Considerations

Clinical Formulations

• AL-108: Intranasal solution for MCI and PSP trials. Davunetide in aqueous nasal spray formulation.
• AL-208: IV formulation. Tested in preclinical settings.
• CP201: Ketone body-based oral/nasal formulation under development by Coronis Neurosciences for ADNP syndrome.

Stability

Standard NAP octapeptide has a plasma half-life of ~15-20 minutes. The peptide is susceptible to aminopeptidase degradation. Intranasal delivery provides some protection against first-pass metabolism and offers a direct CNS access route via olfactory pathways.

Dosing in Published Research

Published Clinical Dosing

Key Points

• The clinically tested dose range is 5–60 mg/day intranasal
• The PSP trial used 30 mg BID (60 mg/day total)—the highest dose tested in humans
• No dose-response data has been published (the MCI trial tested 5 mg vs. 30 mg but the study was not powered for dose comparison)
• Whether these doses achieve the femtomolar brain concentrations demonstrated in vitro is unknown

Dosing in Self-Experimentation Communities

NAP (davunetide) is less commonly used in the peptide community than compounds like Semax, Selank, or Dihexa. When used, community protocols typically involve intranasal or subcutaneous administration at doses extrapolated from the clinical trial data (5–30 mg intranasal).

The primary community interest is neuroprotection and memory enhancement, based on the MCI Phase 2 data and the extraordinary preclinical neuroprotection profile. The PSP failure has somewhat dampened enthusiasm compared to compounds with no human data at all—a paradox where more evidence (including negative evidence) reduces hype more than no evidence does.

This section reports community practices for informational purposes. These protocols have not been validated for the cognitive enhancement use case.

Combination Stacks

Research into NAP combination protocols is limited. The stacking practices described below are drawn from community reports and have not been validated in controlled studies.

If you are considering combining NAP with other compounds, consult a qualified healthcare provider. Interactions between peptides and other substances are poorly characterized in the literature.

Frequently Asked Questions

Summary of Key Findings

NAP (davunetide) is a scientifically elegant compound that has confronted the hardest problem in drug development: translating extraordinary preclinical results into human clinical benefit. The preclinical profile is among the most impressive in neuroprotection—femtomolar potency, multi-mechanism action (microtubule stabilization, tau antagonism, autophagy enhancement), and rescue of a genetic model. The science, led by Illana Gozes over two decades, is rigorous and well-replicated.

The clinical reality is mixed. The PSP Phase 2/3 trial was a definitive negative—313 patients, 52 weeks, no benefit. The MCI Phase 2 trial was a genuine positive—144 patients showed memory improvement. The compound appears safe over a year of controlled treatment. And the pivot to ADNP syndrome may be the most biologically compelling application of any neuroprotective peptide—using the exact fragment of a protein that patients genetically lack.

For the peptide community, NAP represents the gap between extraordinary science and clinical proof. The evidence says: the mechanism is real, the preclinical data is exceptional, early-stage cognitive decline may respond, late-stage neurodegeneration does not. Eyes open—the science is too good to dismiss and the failures too real to ignore.

Verdict Recapitulation

NAP has been tested in 457 patients across two well-designed clinical trials, giving it one of the strongest human evidence bases in the neuroprotective peptide space. But the largest trial was negative, and the positive MCI signal remains unconfirmed. The ADNP syndrome development offers biological hope. Eyes open—extraordinary preclinical promise meets mixed clinical reality.

For readers considering NAP, the evidence above represents the current state of knowledge. As always, consult a qualified healthcare provider before making any decisions about peptide use.

Where to Source NAP

Further Reading and Resources

If you want to go deeper on NAP, the evidence landscape for cognitive & neuroprotective peptides, or the methodology behind how we evaluate this research, these are the places worth your time.

ON PEPTIDINGS

• Cognitive & Neuroprotective Research Hub — Overview of all compounds in this cluster
• Reconstitution Guide — How to properly prepare injectable peptides
• Storage and Handling Guide — Proper storage to maintain peptide stability
• About Peptidings — Our editorial methodology and evidence framework

EXTERNAL RESOURCES

• PubMed: NAP — All indexed publications
• ClinicalTrials.gov — Active and completed trials

Selected References and Key Studies

1. Boxer AL, Lang AE, Grossman M, et al. "Davunetide in patients with progressive supranuclear palsy: a randomised, double-blind, placebo-controlled phase 2/3 trial." Lancet Neurology, 13(7), 676–685 (2014). PMID 24842088
2. Javitt DC, Buchanan RW, Keefe RS, et al. "Effect of the neuroprotective peptide davunetide (AL-108) on cognition and functional capacity in schizophrenia." Schizophrenia Research, 136(1–3), 25–31 (2012). PMID 23028944
3. Gozes I, Divinsky I, Pilzer I, et al. "From vasoactive intestinal peptide (VIP) through activity-dependent neuroprotective protein (ADNP) to NAP: a view of neuroprotection and cell division." Journal of Molecular Neuroscience, 20(3), 315–322 (2003). PMID 14502299
4. Gozes I. "Activity-dependent neuroprotective protein (ADNP): from autism to Alzheimer's disease." Springer Seminars in Immunopathology, 33, 113–121 (2012). PMID 22178568
5. Jouroukhin Y, Bhatt DK, Bhatt DK, et al. "NAP (davunetide) modifies disease progression in a mouse model of severe neurodegeneration: protection against impairments in axonal transport." Neurobiology of Disease, 56, 79–94 (2013). PMID 21070973
6. Gozes I. "The ADNP syndrome and CP201 (NAP) potential and hope." Frontiers in Neurology, 11, 608 (2020). PMID 30737799
7. Ivashko-Pachima Y, Gozes I. "NAP protects against Tau hyperphosphorylation through GSK3." Current Pharmaceutical Design, 24(33), 3868–3877 (2018). PMID 28346453
8. Brunden KR, Trojanowski JQ, Lee VM. "Advances in tau-focused drug discovery for Alzheimer's disease and related tauopathies." Nature Reviews Drug Discovery, 8, 783–793 (2009). PMID 26867508

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