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CSTI-500

Triple Monoamine Reuptake Inhibitor for the treatment of hyperphagia and other neurobehavioral challenges in Prader-Willi Syndrome.

Overview

CSTI-500 is First-in-Class, orally administered New Chemical Entity (NCE), Triple Monoamine Reuptake Inhibitor (TRI). By simultaneously inhibiting the reuptake of serotonin, dopamine, and norepinephrine, CSTI-500 can address the often-reduced levels of these neurotransmitters in PWS patients. It is an optimally balanced TRI with unique pharmacological features that allow for predictable and safe titration to an efficacious dose tailored to the individual patient.

CSTI-500 was generally safe and well-tolerated and has a half-life of 50 hours in Phase I clinical trials. Also importantly, it demonstrated CNS target engagement via positron emission tomography (PET) that predicts efficacy in patients. CSTI-500 is now posed for Phase 2 development.

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Mechanism of Action

CSTI-500 has the potential to provide a transformative therapy, not just for addressing hyperphagia in PWS, but also for tackling many of the associated psychiatric co-morbidities.

CSTI-500 modulates three monoamines involved in appetite, mood, and behaviors.

Tunable & Personalized Dosing


ConSynance holds the exclusive global rights to CSTI-500.

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Relationship between CSTI-500 blood drug concentrations and transporter blockade

Why It Matters?

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  • Offers a potential single-agent approach for PWS’s complex neuropsychiatric profile.

  • Enables personalized balance between efficacy & tolerability

  • Uses PK-Guided, individualized dosing to keep each patient in the optimal therapeutic window

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In short, CSTI-500’s tunable mechanism and individualized dosing strategy potentially offers a novel way to address the full spectrum of PWS symptoms safely and effectively.

Note: The clinical benefit of CSTI-500 has yet to be confirmed in trials, and further research is underway.

Clinical Development Status

  • Generally safe and well-tolerated in Phase I studies in healthy volunteers (n = 87)

  • Demonstrated CNS target engagement via Positron Emission Tomography (PET) imaging

  • Phase I in PWS patients completed (n = 10), confirming PK and tolerability in the target population

  • Phase II study initiating in 2025

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