ThalassaX Therapeutics United States has dosed the first patient in its Phase I clinical trial of CS231295, a brain-penetrant Aurora B kinase selective inhibitor.
The open-label, dose-escalation study is assessing CS231295 in patients with advanced solid tumours and aims to evaluate the therapy’s tolerability, safety, pharmacokinetics, and preliminary anti-tumour activity.
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The company developed CS231295 using its AI-powered chemogenomic technology platform.
ThalassaX Therapeutics stated that the development strategy for the molecule has focused on simultaneous investigational new drug (IND) submissions in China and the US.
It placed particular emphasis on cancers that are challenging to treat, such as retinoblastoma 1 (RB1)-deficient cancers and brain metastases.
ThalassaX Therapeutics United States chairman Dr Xianping Lu said: “We are grateful to the patients and clinical sites for their support.
“From the outset, the global development strategy for CS231295 has centred on parallel Sino US IND submissions, targeting two of the most challenging solid-tumour settings: RB1 deficient cancers and brain metastases.
“Launching clinical development in the US – one of the world’s core markets for innovative oncology therapeutics – marks a milestone of deep strategic significance for our team.”
CS231295 aims to provide a precise inhibition of tumour-specific Aurora B overexpression and induce synthetic lethality in genetically vulnerable tumours like those with RB1 deficiency.
Preclinical research has demonstrated pharmacodynamic activity, favourable pharmacokinetics, and a good safety profile, and ThalassaX Therapeutics states that no similar drug candidate has previously entered global clinical trials.
The compound received IND approval from the National Medical Products Administration (NMPA) in China in December 2024, with initial dosing in May 2025.
The programme obtained IND clearance from the US Food and Drug Administration in July 2025, enabling parallel development in both regions.
