Developer · United States
Syndeio Biosciences, Inc.
Gate Neurosciences was a private, clinical-stage CNS biotechnology company (founded 2019, Indianapolis, Indiana) developing next-generation NMDA receptor modulators for depression, led by zelquistinel (oral) and apimostinel (intravenous). In May 2025 Gate combined with Boost Neuroscience and relaunched as Syndeio Biosciences, which now holds the zelquistinel and apimostinel programs.
Pipeline (2)
- Major depressive disorderPhase 2Recruiting
- Major depressive disorderPhase 2Recruiting
Deals & partnerships
- Apimostinel (GATE-202)Led by Syndeio Biosciences, Inc.Licensor AbbVie Inc.
- Zelquistinel (GATE-251)Led by Syndeio Biosciences, Inc.Licensor AbbVie Inc.
- May 27, 2025AcquisitionGate Neurosciences combines with Boost Neuroscience and relaunches as Syndeio BiosciencesGate Neurosciences (which had agreed in February 2025 to acquire synapse-platform company Boost Neuroscience) relaunched on May 27, 2025 as Syndeio Biosciences, a synapse-targeted neurotherapeutics company. Syndeio now holds Gate's clinical pipeline including zelquistinel (Phase 2, MDD) and apimostinel (Phase 2, acute depression). Private; backed by Catalio Capital, Innoviva, Tenmile, Luson Bioventures and Palo Santo, with AbbVie and Lilly as strategic shareholders.
- Sep 2022Licensing dealGate Neurosciences in-licenses zelquistinel (GATE-251) from AbbVieGate licensed the oral third-generation NMDA receptor modulator zelquistinel (formerly AGN-241751) from AbbVie, alongside apimostinel and rapastinel. The molecules originated at Naurex, were advanced by Allergan, and passed to AbbVie via its Allergan acquisition. Announced September 2022 when Gate emerged from stealth.
- Sep 2022Licensing dealGate Neurosciences in-licenses apimostinel (GATE-202) from AbbVieGate acquired global rights to the second-generation intravenous NMDA receptor modulator apimostinel from AbbVie, alongside zelquistinel and rapastinel. The molecules originated at Naurex, were advanced by Allergan, and passed to AbbVie via its Allergan acquisition. Announced September 2022 when Gate emerged from stealth.
Catalysts · 1 upcoming · 1 reported
- 2029Anticipated
Apimostinel (GATE-202)forMajor depressive disorderTopline data
Phase 2 apimostinel +/- ASAT in MDD: primary completion anticipated 2029
Recently reported
- 2015-02-01pending
Apimostinel (GATE-202)forMajor depressive disorderTopline data
Naurex Phase 2 (NCT02067793): single-dose IV apimostinel reported rapid 24-hour antidepressant effect
Recent activity
- Jan 5, 2026Phase changeZelquistinel (GATE-251)·Major depressive disorderPhase 2Second Phase 2 MDD study NCT07115329 started.source ↗
- Feb 3, 2025Phase changeZelquistinel (GATE-251)·Major depressive disorderPhase 2Phase 2 MDD study NCT06547489 started.source ↗
- Oct 28, 2024Phase changeApimostinel (GATE-202)·Major depressive disorderPhase 2Investigator-led Phase 2 study NCT06400121 (apimostinel 10 mg IV +/- ASAT digital training; U. Pittsburgh / Syndeio) started.source ↗
- Feb 28, 2015Phase changeApimostinel (GATE-202)·Major depressive disorderPhase 2Naurex/Allergan Phase 2 dose-ranging IV study (NCT02067793, 1/5/10 mg, n=151) completed.source ↗
- Feb 1, 2015ReadoutApimostinel (GATE-202)·Major depressive disorderpendingNaurex Phase 2 (NCT02067793): single-dose IV apimostinel reported rapid 24-hour antidepressant effectsource ↗
Trials recruiting · 3 recruiting of 4 sponsored
- Phase 2Zelquistinel (GATE-251)
Phase 2 Study of Oral GATE-251 (Zelquistinel) for Major Depressive Disorder
- Phase 2Zelquistinel (GATE-251)
Phase 2 Study of Oral GATE-251 (Zelquistinel) for Major Depressive Disorder
- Phase 2Apimostinel (GATE-202)
Phase 2, Randomized, Double-Blind, Placebo-Controlled, Single Intravenous Dose, Parallel Efficacy Study of Apimostinel With or Without Subsequent Automated Self-Association Training in Subjects With Major Depressive Disorder
Competitive landscape
Other companies developing against Syndeio Biosciences, Inc.'s targets or indications.
- Boehringer Ingelheim International GmbH2 compoundsGluN2BMajor depressive disorder
- Neurocrine Biosciences, Inc.2 compoundsGluN2BMajor depressive disorder
- Alto Neuroscience, Inc.2 compoundsMajor depressive disorder
- Autobahn Therapeutics, Inc.1 compoundMajor depressive disorder
- Axsome Therapeutics, Inc.1 compoundMajor depressive disorder
- Beckley Psytech Limited1 compoundMajor depressive disorder
- Biohaven Ltd.1 compoundMajor depressive disorder
- Cerevel Therapeutics Holdings, Inc.1 compoundMajor depressive disorder
- COMPASS Pathways plc1 compoundMajor depressive disorder
- CSPC ZhongQi Pharmaceutical Technology (Shijiazhuang) Co., Ltd.1 compoundMajor depressive disorder
- Definium Therapeutics, Inc.1 compoundMajor depressive disorder
- Delix Therapeutics, Inc.1 compoundMajor depressive disorder
Leadership & advisors (11)
Former leadership & advisors (1)
- Aaron Koenig — Chief Medical Officer