Sosei Heptares’ Partner Neurocrine Biosciences Confirms its Plans to Evaluate Two New Muscarinic Agonist Candidates in Phase 1 Clinical Studies

• Both NBI-1117569 (an M4-preferring agonist) and NBI-1117567 (an M1-preferring agonist) are investigational, oral, muscarinic agonists discovered by Sosei Heptares that may have the potential to treat neurological and neuropsychiatric conditions
• Neurocrine Biosciences confirmed a Phase 1 clinical study of NBI-1117569 has started and a Phase 1 study of NBI-1117567 will be initiated in 2024

Tokyo, Japan and Cambridge, UK, 6 December 2023 – Sosei Group Corporation (“the Company”; TSE: 4565), notes its partner Neurocrine Biosciences Inc. (“Neurocrine”; Nasdaq: NBIX), a leading neuroscience-focused biopharmaceutical company, has confirmed its plans to evaluate two new muscarinic agonist candidates in Phase 1 first-in-human clinical studies. The studies are designed to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of NBI-1117569 and NBI-1117567 in healthy adult participants. NBI-1117569, a muscarinic M4-preferring agonist, and NBI-1117567, a muscarinic M1-preferring agonist are both investigational, oral compounds that may have the potential to treat neurological and neuropsychiatric conditions and were developed utilizing Sosei Heptares' structure-based drug design platform. Neurocrine confirmed a Phase 1 clinical study of NBI-1117569 has started and a Phase 1 study of NBI-1117567 will be initiated in 2024.

Matt Barnes, President of Heptares Therapeutics and Head of UK R&D, said: “We are delighted that Neurocrine is progressing these unique M4-preferring and M1-preferring agonists into clinical development to target important unmet medical needs in neurological and neuropsychiatric disorders. NBI-1117569 and NBI-1117567 are the third and fourth candidates to advance into clinical trials from the portfolio of selective muscarinic receptor agonists discovered and licensed by Sosei Heptares to Neurocrine in 2021. Neurocrine has the largest portfolio of muscarinic compounds in clinical development, and we look forward to future progress under this highly productive partnership, including the Phase 2 clinical data on NBI-1117568, a muscarinic M4 selective agonist, expected in the second half of 2024.”

The clinical development milestones achieved with both compounds as announced do not trigger a milestone payment from Neurocrine to Sosei Heptares under the terms of the 2021 agreement between the companies. Milestone payments, under the agreement, are payable upon the achievement of multiple, defined development events for each program. Sosei Heptares will announce the receipt of any milestone payments in accordance with TSE reporting requirements.