Sydney, Australia, September 21, 2026
Kazia Therapeutics Limited has announced that its development partner Sovargen Co., Ltd. has dosed the first patient in a Phase 1b/2a clinical trial evaluating paxalisib for rare, treatment-resistant seizure disorders associated with focal cortical dysplasia type 2 (FCD T2) and tuberous sclerosis complex (TSC). The clinical milestone expands development of paxalisib beyond its primary oncology applications and triggers a $2 million development milestone payment to Kazia under its exclusive licensing agreement with Sovargen. The investigational therapy is being studied as a potential treatment for mTORopathy-related epilepsies, an area with significant unmet medical need.
Paxalisib Enters Clinical Testing for Rare Epilepsies
The Phase 1b/2a study is evaluating paxalisib, also known as SVG103, in adults with rare neurological disorders driven by abnormal activation of the PI3K/Akt/mTOR pathway. Sovargen is developing the therapy for mTORopathy-related epilepsies, including FCD T2, TSC, and hemimegalencephaly (HME). These conditions can result from genetic alterations that cause excessive mTOR pathway activity and contribute to drug-resistant seizures. According to the companies, there are currently no approved therapies specifically for FCD T2, underscoring the need for new therapeutic approaches. Paxalisib is an oral, brain-penetrant dual PI3K/mTOR inhibitor designed to reach the central nervous system and target signaling pathways implicated in disease biology.
The first-patient dosing milestone marks the transition of the program into an important clinical evaluation stage. The study is intended to generate clinical data on the safety, tolerability, and potential therapeutic activity of paxalisib in patients with these rare and intractable epilepsies. Because the disorders are associated with abnormal mTOR signaling, targeting this pathway represents a mechanism-based approach to investigating whether pharmacological inhibition can help address the underlying biology contributing to seizure activity. The clinical investigation will provide additional evidence needed to determine the potential role of paxalisib in these patient populations.
Licensing Agreement Expands Paxalisib Development
Advertisement
Kazia and Sovargen entered into an exclusive licensing agreement in March 2024, under which Sovargen assumed responsibility for the development, manufacturing, and commercialization of paxalisib for mTORopathy-related epilepsies in most global territories, excluding mainland China, Hong Kong, Macao, and Taiwan. The first-patient dosing milestone triggers the $2 million payment to Kazia, while the agreement provides for additional development and regulatory milestone payments of up to $17 million, together with potential sublicensing revenues and royalties on net sales of products incorporating paxalisib.
For Kazia, the program represents an opportunity to extend the development of paxalisib beyond oncology. The company originally developed the drug as an investigational treatment targeting the PI3K/Akt/mTOR pathway in cancer, while Sovargen is applying the compound to neurological diseases in which the same signaling pathway is implicated. Kazia continues to focus its own clinical development activities on oncology, while Sovargen leads the rare-neurology program.
Clinical Development Targets Significant Unmet Need
FCD T2 and TSC are rare neurological disorders that can cause persistent seizures that are difficult to control with existing treatments. FCD involves abnormal development of the cerebral cortex, while TSC is a genetic disorder associated with abnormal cell growth and neurological manifestations, including epilepsy. In both conditions, dysregulated mTOR signaling can contribute to disease progression and seizure activity. Sovargen’s clinical development strategy is focused on therapies for rare neurological disorders associated with brain somatic mosaicism, supported by research platforms for identifying disease-causing mutations, validating therapeutic targets, and evaluating candidate treatments. The advancement of paxalisib into a Phase 1b/2a study represents an important clinical milestone for the program, but the therapy remains investigational for these seizure disorders. Data from the study will be needed to determine its safety, tolerability, and potential clinical benefit. As enrollment progresses, results from the trial are expected to help establish whether PI3K/mTOR pathway inhibition can provide a meaningful therapeutic approach for patients with rare, treatment-resistant epilepsies.
Source: Kazia Therapeutics press release
