Otsuka HD (4578)

Equity Research 27 July 2026 | 1:09AM JST

Otsuka HD (4578.T): First Take: US FDA approval for centanafadine; maintain Buy

Otsuka HD announced on the 24th (US time) that the US FDA has approved Simtriyo Akinori Ueda, Ph.D. | (generic name: centanafadine), a treatment for attention-deficit hyperactivity Goldman Sachs Japan Co., Ltd. disorder (ADHD) (link). We will be closely watching future developments, as we think Tomo Taniguchi the drug has the potential to become a blockbuster if it can establish a position as a | treatment option with a good balance of efficacy and safety, following schedule Goldman Sachs Japan Co., Ltd.

classification (categorization of controlled substances, link) by the US Drug Enforcement Administration (DEA). We maintain our Buy rating.

Key points from Otsuka HD’s announcement The main points of the company’s announcement are as follows.

n Approval from the US FDA: Simtriyo was approved by the US FDA as a treatment for ADHD in adults and pediatric patients aged 6 years and older weighing at least 20 kg. The drug is the first approved NDSRI (norepinephrine, dopamine, and serotonin reuptake inhibitor), and is a once-daily extended-release capsule. n Launch schedule: Otsuka HD plans to launch the drug later this year, following schedule classification by the US DEA. n Safety information: The Boxed Warnings in the prescribing information (link) state that (1) administration of the drug can increase the risk of suicidal thoughts and behaviors, and (2) there is a need to assess the risk of abuse, misuse, and addiction.

Implications The market for ADHD treatments is large, and we will be closely watching future developments, as we think the drug has the potential to become a blockbuster if it can establish a position as a treatment option with a good balance of efficacy and safety.

Positioning as an option with a good balance of efficacy and safety Existing central nervous system (CNS) stimulants, which are widely used for ADHD treatment (accounting for around 80% of prescriptions in the US), are fast-acting, but safety and abuse/addiction are challenges with long-term use. On the other hand, non-stimulants have a low risk of abuse/addiction, but face challenges

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regarding efficacy and the timing of the onset of effect.

As shown below, positive efficacy and safety profiles have been disclosed for centanafadine thus far, and we focus on the potential for the drug to become a treatment option with a good balance of efficacy and safety following the DEA’s schedule classification.

n Efficacy: In four Phase 3 trials, centanafadine demonstrated statistically significant and clinically meaningful improvements in ADHD symptoms versus placebo. In both pediatric and adult trials, improvements in ADHD symptoms were seen from the first week of administration. A treatment effect was also confirmed in patients with comorbid anxiety (link), which is considered difficult to treat. n Safety: Long-term trials demonstrated a favorable safety profile (link). Furthermore, it has been suggested that (1) the risk of adverse events is statistically significantly lower than or comparable to existing treatments (link), and (2) the risk of abuse is lower than that of existing stimulants (link).

Potential for rising blockbuster expectations Our peak sales forecast (for FY12/34E), prior to adjusting for the probability of success (PoS) in the US, is US$400 mn-US$500 mn. We estimate the DCF value per share for the drug at around ¥300 (adjusted for a 70% PoS).

We will be watching future developments, as expectations for peak sales could rise significantly if (1) centanafadine establishes a…