Alto Neuroscience Announces Completion of Enrollment in Phase 2 Proof-of-Concept Study of ALTO-101 in Cognitive Impairment Associated with Schizophrenia

Key Terms

phosphodiesterase-4 (pde4) inhibitor medical

A phosphodiesterase-4 (PDE4) inhibitor is a type of drug that blocks an enzyme responsible for breaking down a key signaling molecule inside cells, which tends to reduce inflammation and other overactive immune responses—think of it as turning down an internal volume knob on inflammatory signals. Investors care because PDE4 inhibitors are used or explored for multiple disorders (skin, lung, brain), so trial results, regulatory decisions, patents and side-effect profiles can materially affect a drug’s commercial potential and a company’s valuation.

transdermal medical

Transdermal describes a method of delivering a drug through the skin so the active ingredient is absorbed into the bloodstream, commonly via a patch, gel or cream. For investors, transdermal delivery affects a product’s convenience, steady dosing, patent and regulatory profile, manufacturing needs and market appeal—similar to a slow-release battery that makes a device easier to use and last longer, which can influence sales potential and risk.

electroencephalography (eeg) medical

Electroencephalography (EEG) records the brain’s electrical activity through sensors placed on the scalp, capturing patterns of brain waves much like a seismograph records tremors. Investors care because EEG data are used to show how neurological drugs, devices and diagnostic tools affect the brain, influencing clinical trial results, regulatory approvals and market adoption that drive a company’s revenue and development timeline.

theta-band inter-trial coherence (itc) medical

Theta-band inter-trial coherence (ITC) is a brain-measure recorded with EEG that quantifies how consistently slow rhythmic activity in the theta frequency range lines up in timing across repeated stimuli or trials; imagine many musicians trying to keep the same beat and a higher score means they stay in time. Investors care because it can serve as an objective biomarker in clinical studies or device testing to show whether a treatment or intervention changes brain timing reliably, information that can influence regulatory decisions, clinical value, and commercial prospects.

mismatch negativity medical

An electrical brain signal picked up by EEG that emerges automatically when the brain detects an unexpected sound or change in a pattern, reflecting early sensory and attention processing. Think of it as a car’s dashboard light that flashes when the brain notices something out of the ordinary; in drug and device trials it serves as an objective test of whether a treatment changes basic brain function, which can affect trial success and valuation.

auditory steady-state response medical

An auditory steady-state response is an objective test that measures the brain’s electrical reaction to continuous, repeating sounds to assess hearing function without requiring a behavioral response. Think of it like checking whether an electrical circuit lights up reliably when a steady signal is applied; for investors, ASSR matters because it is used in device testing, clinical studies and regulatory submissions for hearing diagnostics and therapies, affecting product validation, market approval and reimbursement prospects.

matrics consensus cognitive battery (mccb) medical

A standardized set of brief tests designed to measure key thinking skills—such as memory, attention, speed of processing, reasoning and social understanding—used mainly in clinical trials for psychiatric conditions. Think of it as a report card for different mental abilities that regulators and drug developers use to judge whether a treatment meaningfully improves cognition; for investors, MCCB results can influence a therapy’s perceived value, regulatory chances, and commercial prospects.

cohen’s d technical

Cohen’s d is a simple numerical measure of how large the difference is between two groups, calculated by taking the gap between their average results and scaling it by the typical spread of individual results. Investors use it to judge whether an observed change or treatment is meaningfully big or just a small blip — like saying two players differ by a full game versus a few minutes — which helps assess the real-world importance of trial results, strategy tests, or performance comparisons.

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MOUNTAIN VIEW, Calif.--(BUSINESS WIRE)-- Alto Neuroscience, Inc. (“Alto”) (NYSE: ANRO), a clinical-stage biopharmaceutical company focused on the development of novel precision medicines for neuropsychiatric disorders, today announced the completion of patient enrollment in its Phase 2 proof-of-concept clinical trial evaluating ALTO-101, a novel, transdermal phosphodiesterase-4 (PDE4) inhibitor, for the treatment of cognitive impairment associated with schizophrenia (CIAS). Topline data from the Phase 2 proof-of-concept study are expected following completion of dosing and data analysis and are anticipated to guide future development decisions for ALTO-101.

Cognitive impairment represents a core, persistent feature of schizophrenia affecting nearly all patients and is a major driver of long-term functional disability, for which there are currently no approved pharmacologic treatments.

Alto met its enrollment goal for the Phase 2 proof-of-concept trial (NCT06502964) with 83 CIAS patients enrolled across 13 clinical sites in the United States. The randomized, double-blind, placebo-controlled crossover study is designed to assess the effects of ALTO-101 on electroencephalography (EEG) measures that have been consistently linked to cognitive dysfunction in schizophrenia. Participants in the study receive 10 days of treatment with ALTO-101 or placebo, followed by a washout period, and then 10 days of treatment with the opposite intervention than was received in the first period. This design enables within-subject comparisons and is intended to enhance sensitivity for detecting treatment-related effects on brain-based EEG measures and cognitive endpoints.

“This milestone brings us closer to potentially delivering a first-of-its-kind treatment for the millions of patients suffering from the debilitating cognitive effects of schizophrenia," said Amit Etkin, M.D., Ph.D., founder and chief executive officer of Alto Neuroscience. "Our baseline results have already replicated findings from three independent datasets, reinforcing our confidence in ALTO-101’s mechanism and our biomarker-driven approach. We look forward to reporting data from this study around the end of the first quarter.”

The primary endpoint in the study is theta-band inter-trial coherence (ITC), an EEG measure strongly correlated with cognitive performance, measured during an auditory oddball paradigm. Additional EEG endpoints include resting-state theta power, mismatch negativity, and auditory steady-state response. Cognitive performance will be assessed using select domains of the MATRICS Consensus Cognitive Battery (MCCB) and a computerized measure of processing speed. The study is 80% powered to detect a 0.3 Cohen’s d effect size on the primary outcome measure.

Scientific Rationale and Baseline Findings

Baseline analyses from all screened participants demonstrated a statistically significant association between reduced theta ITC and slower processing speed. These findings replicate prior prospectively analyzed schizophrenia datasets and support the relevance of theta ITC as a translational biomarker for cognitive impairment in CIAS, reinforcing the scientific rationale for the ALTO-101 program.

Alto employed a patient selection strategy based on magnitude of processing speed deficits, and an initial baseline assessment reveals clear enrichment for reduced Theta ITC and cognitive performance in participants enrolled in the trial.

ALTO-101 is administered via a novel, proprietary transdermal delivery system (TDS) developed in collaboration with MEDRx. The TDS formulation is intended to mitigate the gastrointestinal adverse effects commonly associated with oral PDE4 inhibitors, while maintaining central nervous system target engagement.

About ALTO-101

ALTO-101 is a novel small molecule PDE4 inhibitor being developed for cognitive impairment associated with schizophrenia – an indication for which ALTO-101 has been granted Fast Track Designation by the U.S. FDA. Through a proprietary transdermal delivery system, ALTO-101 is designed to provide steady state concentrations to improve drug safety, tolerability, and pharmacokinetics. The proprietary transdermal delivery system for ALTO-101 has been developed in partnership with MEDRx. In Phase 1 clinical trials, ALTO-101 demonstrated human brain penetration, robust CNS-relevant pharmacodynamic effects, and was well tolerated across therapeutically relevant dose ranges.

About Cognitive Impairment Associated with Schizophrenia (CIAS)

Cognitive impairment is a core and disabling feature of schizophrenia, affecting areas such as memory, attention, processing speed, and executive function. These deficits are a primary determinant of poor functional outcomes for patients, impacting their ability to work, maintain social relationships, and live independently. Currently, there are no approved treatments for CIAS, representing a significant unmet medical need for the millions of people living with schizophrenia worldwide.

About Alto Neuroscience

Alto Neuroscience is a clinical-stage biopharmaceutical company with a mission to redefine psychiatry by leveraging neurobiology to develop personalized and highly effective treatment options. Alto’s Precision Psychiatry Platform™ measures brain biomarkers by analyzing EEG activity, neurocognitive assessments, wearable data, and other factors to better identify which patients are more likely to respond to Alto product candidates. Alto’s clinical-stage pipeline includes novel drug candidates in bipolar depression, major depressive disorder, treatment resistant depression (TRD), and schizophrenia, and other mental health conditions.

Forward-Looking Statements

This press release may contain forward-looking statements made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. These statements may be identified by words such as “aims,” “anticipates,” “believes,” “could,” “estimates,” “expects,” “forecasts,” “goal,” “intends,” “look forward,” “may,” “plans,” “possible,” “potential,” “seeks,” “will” and variations of these words or similar expressions that are intended to identify forward-looking statements, although not all forward-looking statements contain these words. Forward-looking statements in this press release include, but are not limited to statements regarding Alto’s expectations about the potential benefits, activity, effectiveness, tolerability, and safety of its product candidates and Precision Psychiatry Platform (“Platform”); statements regarding Alto’s expectations for the design, timing and results of its Phase 2 Proof-of-Concept Study of ALTO-101; Alto’s expectations with regard to the general design and results of its research and development programs and clinical trials; and other statements that are not historical fact. Actual results or events could differ materially from the plans, intentions and expectations disclosed in these forward-looking statements as a result of various factors, including uncertainties inherent in the initiation, progress and completion of clinical trials and clinical development of Alto’s product candidates, and other important factors, any of which could cause Alto’s actual results to differ from those contained in the forward-looking statements, which are described in greater detail in the section titled “Risk Factors” in each of Alto’s Annual Report on Form 10-K for the fiscal year ended December 31, 2024 and Alto’s Quarterly Report on Form 10-Q for the fiscal quarter ended September 30, 2025 filed with the Securities and Exchange Commission (“SEC”) as well as in other filings Alto may make with the SEC in the future. Any forward-looking statements contained in this press release speak only as of the date hereof, and Alto expressly disclaims any obligation to update any forward-looking statements contained herein, whether because of any new information, future events, changed circumstances or otherwise, except as required by law.

Availability of Information on Alto’s Website

Alto routinely uses its investor relations website to post presentations to investors and other important information, including information that may be material. Accordingly, Alto encourages investors and others interested in Alto to review the information it makes public on its investor relations website.

View source version on businesswire.com: https://www.businesswire.com/news/home/20260213343048/en/

Investor and Media Contact:
Nick Smith
investors@altoneuroscience.com
media@altoneuroscience.com

Source: Alto Neuroscience, Inc.