Expands Otsuka portfolio in psychiatric and neurological fields and aims to accelerate development of Transcend's portfolio, including the TSND-201 program for post-traumatic stress disorder (PTSD) –

Otsuka Pharmaceutical Co., Ltd. (Otsuka) and Transcend Therapeutics, Inc. (Transcend) announce that the two companies entered into an agreement  under which Otsuka, through its wholly owned subsidiary Otsuka America, Inc., will fully acquire Transcend. The acquisition is expected to be completed in the second quarter of 2026, subject to the fulfillment of customary closing conditions and required procedures.

Under the terms of the agreement, Otsuka will pay USD 700 million to Transcend shareholders upon closing of the acquisition, and up to USD 525 million in additional contingent consideration based on future sales milestones related to assets in development, for a total potential consideration of USD $1.225 billion.

Transcend, founded in 2021, is a clinical stage biotechnology company developing rapid-acting treatments for neuropsychiatric diseases. TSND-201 (methylone), which the company is developing, is a rapid-acting neuroplastogen—an agent that induces rapid and durable neural plasticity in the brain—and is being advanced as a potential treatment for post-traumatic stress disorder (PTSD) and other psychiatric conditions. In the United States, more than 13 million individuals are estimated to be affected by PTSD each year,¹ yet no new treatments have been approved for 25 years, underscoring the significant unmet medical need.

Recent research has demonstrated that changes in neuroplasticity in the brain are deeply involved in both the onset and persistence of PTSD symptoms. Neuroplasticity, the brain's ability to reorganize neural circuits, supports memory formation and emotional regulation. In PTSD, alterations in fear-related pathways impair the ability to relearn safety ("overwriting fear"), driving growing interest in interventions that restore or enhance neuroplasticity.²

TSND-201 (methylone) acts on monoamine transporters in the brain—including those for serotonin, norepinephrine, and dopamine. By promoting monoamine release, it increases monoamine concentrations within the synaptic cleft, resulting in rapid and sustained enhancement of neuroplasticity.^3,4 Importantly, TSND-201 does not act on the serotonin 5-HT2A receptor, which mediates hallucinogenic effects, and is therefore considered a non-hallucinogenic compound.^3,5

Transcend is also conducting research and development on novel prodrugs—classified as new chemical entities—to further improve the balance of efficacy, safety, and tolerability of TSND‑201. The company has selected a development candidate and is currently performing non‑clinical studies in preparation for an Investigational New Drug application to the U.S. Food and Drug Administration (FDA).

TSND‑201 demonstrated favorable results in the Phase 2 clinical trial IMPACT‑1, which enrolled adults with PTSD, and study findings were published in JAMA Psychiatry in February 2026.⁵ Due to its rapid onset of activity and robust effects, TSND‑201 was granted Breakthrough Therapy designation by the FDA in July 2025. Transcend met with the FDA in September 2025, to discuss company plans to expedite the development of TSND-201 and confirm the design of the Phase 3 study. Patient recruitment for the Phase 3 trial is underway in the U.S.

Makoto Inoue, president and representative director of Otsuka, commented, "We are very pleased to welcome Transcend Therapeutics into the Otsuka group. Although treatment options for PTSD remain limited, TSND‑201 is generating expectations as a potential paradigm‑shifting therapy in the field of psychiatry. By combining Otsuka's long‑standing expertise in the psychiatric and neurological fields with Transcend's innovative approach, we will advance the development of TSND-201 in close collaboration with regulatory authorities to bring this new treatment option to patients."

Blake Mandell, CEO and co-founder at Transcend Therapeutics, noted, "We founded Transcend to bring a fundamentally new treatment to patients with PTSD–one that is rapid-acting and accessible. Otsuka's leadership and longstanding commitment in neuroscience reflect the same dedication to patients that has driven our team from day one, and we are proud to continue advancing TSND-201 together in service of that shared mission."

Since the 1970s, Otsuka Pharmaceutical has focused on the psychiatric and neurological fields, working to provide new treatment options for disorders such as schizophrenia, bipolar disorder, depression and PTSD, for which therapeutic choices remain limited. In recent years, with the aim of creating next-generation therapies for psychiatric disorders, Otsuka has expanded its global network through partnerships and collaborations, as well as by the acquisition of Mindset Pharma, Inc., a company with innovative, serotonin 5-HT2A agonist discovery technology. Through these efforts, the company is actively working to broaden future treatment options.

By acquiring TSND‑201—a novel investigational asset with a mechanism of action distinct from Otsuka's existing medicines and development programs—the company will further accelerate the expansion of its portfolio in the psychiatric and neurological fields. In the U.S. in particular, despite the very large number of individuals living with PTSD, treatment options remain limited to psychotherapy and antidepressants, underscoring the need for new therapeutic approaches supported by scientific evidence of efficacy and safety. By welcoming Transcend into the Otsuka group, the company aims to strengthen its position as a global leader in the psychiatric and neurological fields and to accelerate the development of next‑generation treatments, including those for PTSD, with the goal to expand future treatment options.