What changed, and when

Syremis Therapeutics launches with $165M Series A to advance a dual M1/M4 muscarinic agonist, ST-905, in Phase 1 for schizophrenia and a novel NMDA antagonist, ST-901, in IND-enabling studies, with the round co-led by Dexcel Pharma and Third Rock Ventures and participation from Bain Capital Life Sciences, GV, QVT and Pictet. (Business Wire press release)
Independent coverage confirms the terms and names former Karuna CEO Steve Paul as a co-founder alongside Clexio co-founder and CEO Elisabeth Kogan, with programs originally discovered at Clexio. (Fierce Biotech, Endpoints News, Reuters summary)
Note the company website lists the launch item dated 15 Dec 2025, which we treat as a site posting date, privileging the 18 Dec wire distribution as the formal announcement. (Syremis website)

60-second thesis frame

The muscarinic M1/M4 class is validated by FDA-approved Cobenfy (xanomeline, trospium) for schizophrenia in 2024, creating room for best-in-class entrants that improve potency, tolerability and dosing. (FDA label, FDA approval notice) Syremis’ ST-905 aims for once-daily oral and a long-acting injectable profile, and ST-901 adds optionality in depression via NMDA antagonism; both originated at Clexio with experienced operators from Teva, Third Rock and Karuna at the helm. (Business Wire press release, Fierce Biotech) Class risk remains real, including cholinergic adverse events and emerging muscarinic competitors like MapLight’s ML-007C-MA in Phase 2, so proof-of-concept data, dosing convenience and payer access analogs to Cobenfy will determine edge. (MapLight IPO releases, Fierce Biotech on MapLight)

The seven diligence questions

Clinical

• What magnitude and domain-level effects will ST-905 show on PANSS and cognition versus placebo in first PoC, and with what cholinergic AE burden relative to xanomeline-based therapy? (Class benchmark, FDA label Cobenfy)
• Does once-daily exposure for ST-905 translate into adherence and tolerability gains, and is a long-acting injectable formulation technically viable by PK/PD? (Business Wire press release)

Payer or Access

• If Cobenfy analogs face prior authorization and new-to-market reviews, what hurdles should Syremis plan for at launch, and which real-world endpoints will payers want? (UHC policy excerpt, Cobenfy HCP PA guide)
• How will Medicare LIS and commercial copay dynamics observed for Cobenfy shape pricing headroom and patient affordability for a follow-on muscarinic? (Cobenfy support page)

Ops or Adoption

• Can Syremis operationalize parallel oral and LAI paths without stretching CMC and trial ops, given a lean team and dual-asset plan? (Business Wire press release)

Competitive

• How will ST-905 differentiate against Cobenfy and MapLight’s ML-007C-MA on efficacy, GI AEs and dosing schedule, and what is the timing overlap for mid- to late-stage readouts? (FDA label Cobenfy, MapLight Phase 2 timelines)

Team or Cap table

• With Dexcel as strategic co-lead, Third Rock on the board and Steve Paul as co-founder, what governance and follow-on support exist to finance Phase 2, and how much optionality remains for BD? (Business Wire press release, Fierce Biotech)

Red flags

• If ST-905 fails to demonstrate a clinically meaningful PANSS benefit with improved tolerability over Cobenfy, the best-in-class claim weakens. (Benchmark, FDA label Cobenfy)
• Muscarinic field competition accelerates, for example if MapLight’s Phase 2 reads out positively ahead of Syremis PoC, compressing differentiation windows. (MapLight timelines)
• Class narrative turns if high-profile studies underperform, as seen in certain Cobenfy settings, resetting payer and prescriber enthusiasm. (Reuters on add-on miss, Reuters on trial shortfall)

Next catalyst

ST-905 Phase 1 progression and first PoC path selection, plus ST-901 first-in-human start targeted for 2026 per the launch materials. (Business Wire press release, Syremis pipeline page)

FAQ

• What exactly changed by Syremis Therapeutics’ launch and $165M financing news on 18 Dec 2025, and why does it matter for the Schizophrenia market?
  Syremis Therapeutics officially launched as a clinical-stage biotech with a significant $165M Series A round to develop next-generation neuropsychiatric drugs (Business Wire). It matters because the company is led by the former CEO of Karuna Therapeutics and aims to improve upon the first-in-class muscarinic treatments recently approved for schizophrenia (Fierce Biotech).
• What is the regulatory path after Syremis’ launch, and what are the next formal steps in the US?
  Syremis is currently conducting Phase 1 clinical trials for its lead asset, ST-905, in schizophrenia (Business Wire). The company also plans to submit an Investigational New Drug (IND) application for its second asset, ST-901, to begin human trials for depression in 2026 (FirstWord Pharma).
• Which assets drove Syremis’ Series A funding, and what are their mechanisms?
  The financing was driven by ST-905, a dual M1/M4 muscarinic receptor agonist, and ST-901, a novel NMDA receptor antagonist (Business Wire). These mechanisms target established but underserved pathways in schizophrenia and major depressive disorder (FirstWord Pharma).
• What safety issues matter post-Syremis’ launch, and could they change real-world use?
  Muscarinic agonists can trigger GI, urinary and cardiac precautions; Cobenfy’s label highlights monitoring for hepatic labs and heart rate, which payers and prescribers may apply as class expectations. (FDA label Cobenfy)
• Who are the key leadership figures behind Syremis Therapeutics?
  The company was co-founded by CEO Elisabeth Kogan and Steve Paul, MD, the latter of whom was the architect of Karuna’s $14 billion exit to BMS (Fierce Biotech). The leadership team includes several former Teva Pharmaceuticals executives who previously worked together at Clexio Biosciences (FirstWord Pharma).

Publisher / Disclosure

Publisher: LucidQuest Ventures Ltd. Produced: 19 Dec 2025, 11:00 London. Purpose: general and impersonal information. Not investment research or advice, no offer or solicitation, no suitability assessment. UK: directed at investment professionals under Article 19(5) and certain high-net-worth entities under Article 49(2)(a)–(d) of the Financial Promotion Order 2005. Others should not act on this. Sources and accuracy: public sources believed reliable, provided “as is,” may change without notice. No duty to update. Past performance is not reliable. Forward-looking statements carry risks. Methodology: questions-first framework using public sources. No conflicts. Authors do not hold positions unless stated. © 2025 LucidQuest Ventures Ltd.

Entities / Keywords

Syremis Therapeutics; ST-905; ST-901; muscarinic M1/M4 agonist; next-generation NMDA antagonist; schizophrenia; psychosis; major depressive disorder; bipolar depression; Clexio Biosciences; Elisabeth Kogan; Steve Paul; Elena Kagan; Menashe Levy; Ilan Oren; Reid Huber; Ray Sanchez; Dexcel Pharma; Third Rock Ventures; Bain Capital Life Sciences; GV; QVT; Pictet; Leerink Partners; Karuna Therapeutics; Bristol Myers Squibb; Cobenfy; KarXT; FDA; IND-enabling; Phase 1; Phase 2; payer prior authorization; MapLight Therapeutics; ML-007C-MA; Tel Aviv; Boston.