Jazz Pharmaceuticals Inks $1B Deal for SAN2355, a Selective Kv7.2/7.3 Potassium Channel Activator for Epilepsy

On August 21, 2025, it was announced that Jazz Pharmaceuticals (“Jazz”) and Saniona had entered into a global licensing agreement, under which Saniona granted Jazz exclusive worldwide development rights to SAN2355. SAN2355 is a differentiated potassium channel activator being developed primarily for epilepsy and other potential indications, aiming to overcome the limitations of non-selective Kv7-targeting compounds.

Under the terms of the agreement, Jazz will lead and fund the further development, regulatory filings, and global commercialization activities for SAN2355.Jazz will make an upfront payment of $42.5 million and is eligible to pay up to $192.5 million in development and regulatory milestone payments, including a $7.5 million payment upon the initiation of Phase I studies for SAN2355. In addition, Saniona is eligible to receive up to $800 million in commercial milestone payments, as well as tiered royalties on net sales ranging from single digits to double digits, bringing the total potential value to approximately $1 billion.

According to statistics from the World Health Organization (WHO), epilepsy affects approximately 50 million people worldwide. The condition is characterized by recurrent seizures. During an epileptic seizure, brief involuntary convulsions occur in a specific part of the body or throughout the entire body (i.e., focal or generalized seizures), sometimes accompanied by loss of consciousness and urinary or fecal incontinence.

Seizures are caused by abnormal electrical discharges from a group of brain cells. Different regions of the brain can serve as foci for these abnormal discharges. Seizures range from brief lapses in consciousness or muscle reflexes to severe and persistent convulsions. The frequency of seizures also varies, ranging from fewer than one episode per year to several episodes per day.

Existing antiepileptic drugs face challenges such as efficacy ceilings, toxicity, multisystem adverse reactions, and poor adherence.

Among patients with epilepsy, approximately 30% have drug-resistant epilepsy, with seizures remaining uncontrolled despite combined treatment with traditional sodium channel blockers and GABAergic agents.

Classic drugs such as phenytoin and carbamazepine have a narrow therapeutic window; slightly elevated blood drug concentrations can lead to ataxia and hepatotoxicity, while slightly subtherapeutic levels result in disease recurrence. The need for multiple daily doses leads to significant cumulative side effects, making it difficult for most patients to adhere to the prescribed regimen and dosage. This poor adherence substantially compromises treatment efficacy and directly increases relapse rates.

It is not that challengers have failed to attempt to break this deadlock. Early studies have demonstrated that Kv7 ion channels are a critical mechanism in controlling seizures. Kv7 ion channels are voltage-gated potassium channels that play a key role by inhibiting repetitive neuronal firing, which can lead to seizures.

To this end, GSK previously launched the first-generation Kv7 activator Potiga (ezogabine). However, due to serious side effects such as retinal pigmentation, urinary retention, and skin disorders, the drug was withdrawn globally in 2017.

Evidence suggests that skin discoloration and retinal changes are caused by the chemical instability of Potiga, rather than its mechanism of action, while the increased risk of urinary retention is attributed to the non-selective nature of ezogabine, leading to unintended activation of Kv7 subtypes expressed in the bladder.

Building on this, Saniona’s R&D team confirmed that the activation of Kv7.4 and Kv7.5 is a key factor contributing to side effects such as retinal pigmentation and urinary retention caused by Potiga. Therefore, unlike Potiga, the molecular design of SAN2355 focuses on avoiding activation of the Kv7.4/7.5 subtypes.

To this end, SAN2355 features a chemical structure that is entirely distinct from Potiga, theoretically reducing the risk of cutaneous and ocular adverse reactions, thereby achieving a more optimal balance between efficacy and safety.

Currently, SAN2355 is regarded as a selective, potentially “best-in-class” small-molecule activator of Kv7.2/Kv7.3 potassium channels, with a mechanism of action confirmed to suppress seizure activity. SAN2355 specifically targets the Kv7.2/Kv7.3 subtypes, thereby inhibiting seizure-related Kv7 isoforms while avoiding activation of other Kv7 subtypes. This high selectivity enables dose optimization for SAN2355 without compromising efficacy.

In addition to SAN2355, Saniona is also focused on discovering, developing, and delivering innovative therapies for neurological and psychiatric disorders. The company’s internal R&D pipeline includes SAN2219 for the treatment of epilepsy and SAN2465 for the treatment of major depressive disorder.

Notably, Saniona had previously entered into a development collaboration with BI, and in November 2024, it partnered with Acadia Pharmaceuticals (“Acadia”) to jointly develop and commercialize SAN711 for the treatment of neurological disorders.

The collaboration with Acadia positions Saniona to receive up to $610 million in funding, including a $28 million upfront payment and up to $582 million in development, regulatory, and commercial milestone payments, as well as tiered royalties in the mid-single to low-double digits on global net sales of SAN711. Additionally, Acadia will provide financial support for Saniona’s ongoing Phase I clinical studies and preparations for Phase II clinical trials.

In fact, in recent years, Jazz Pharmaceuticals has invested heavily in the oncology field, but its two highest-revenue-generating drugs still come from neuroscience. The first is Xywav, a medication for the treatment of narcolepsy, which achieved sales of $760.1 million in the first half of 2025; the other is its oral cannabidiol solution, marketed as Epidiolex in the United States and as Epidyolex in Europe, which generated $469.5 million in revenue during the same period.

The inclusion of Epidiolex stems from Jazz’s $7.2 billion acquisition of GW Pharmaceuticals in 2021. Currently, Epidiolex has become a blockbuster product in Jazz’s pipeline, and the addition of SAN2355 signals the company’s intent to further solidify its position in the epilepsy and broader neuroscience markets.

Jazz’s Xywav patents are set to expire sequentially starting in 2027, necessitating new growth drivers for its epilepsy segment. If the subsequent development of SAN2355 proceeds smoothly, it is projected to launch around 2030 based on a five- to six-year timeline, thereby ensuring a seamless transition. Leveraging its existing anti-epilepsy brands such as Epidiolex, Jazz has established market presence and sales networks across multiple countries. This infrastructure would allow SAN2355 to be directly “plugged into” the current sales force, continuously reducing marginal sales costs.

Meanwhile, this transaction also offers valuable insights for domestic biotech companies. Saniona’s R&D strategy—avoiding the systemic toxicity associated with “broad-spectrum channel” modulators by focusing on precise subtype selectivity—provides a reference model for molecular innovation in China. The total deal value of $1 billion also establishes a pricing anchor for negotiations involving promising domestic pipelines.

Domestically, on April 15, 2024, Baicheng Medicine announced that the National Medical Products Administration had approved the clinical trial for its independently developed drug, 2023HY252, as an adjunctive therapy for partial-onset seizures in epilepsy patients aged 12 years and older.

NS-041, a Class 1 new drug developed by Livzon Pharmaceutical Group, demonstrates the potential to become a best-in-class therapy as a next-generation KCNQ2/3 activator, owing to its high target selectivity and unique molecular design.

In preclinical studies, NS-041 demonstrated its advantages in target selectivity and therapeutic window. Preclinical in vitro data showed that NS-041 exhibited greater selectivity and affinity for KCNQ2/3 targets compared to other international drugs of the same class, resulting in a wider therapeutic window. Results from Phase I clinical trials indicated that NS-041 not only displayed favorable pharmacokinetics but also had no serious ocular adverse events observed, along with fewer adverse effects on the nervous system.

Yisi Biopharma has introduced cenobamate tablets and solriamfetol tablets. These two drugs are indicated for the treatment of partial-onset seizures in adult patients with epilepsy and excessive daytime sleepiness associated with obstructive sleep apnea syndrome, respectively. Notably, a New Drug Application (NDA) for cenobamate tablets has been submitted in China, and Phase III clinical trials have been conducted.

If Saniona’s Phase I data for SAN2355 validate the hypothesis of precise targeting, this novel drug is poised to become the next blockbuster in the epilepsy field after Epidiolex around 2030; meanwhile, this deal will provide another classic paradigm for Chinese innovative pharmaceutical companies: “target selection–preclinical validation–overseas licensing.”