The first patient with gastrointestinal stromal tumor (GIST) has been treated with the experimental drug THE-630 as part of an ongoing phase 1/2 clinical trial, according to a press release from Theseus Pharmaceuticals, the developers of the drug.

“The initiation of our Phase 1/2 trial in patients with previously-treated advanced GIST is an important milestone as we begin to characterize THE-630 in the clinic,” David Kerstein, MD, chief medical officer at Theseus said.

“I look forward to evaluating its clinical potential to address the needs of patients with advanced GIST,” Suzanne George, MD, clinical director at the Center for Sarcoma and Bone Oncology at Dana-Farber Cancer Institute in Boston, Massachusetts added.

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GISTs are the most common mesenchymal abnormal cell growths of the gastrointestinal tract. Most cases are caused by a gain of function mutations in the KIT gene, which encodes transmembrane receptor tyrosine kinase proteins. 

Read more about GIST etiology

A radical surgical resection is a treatment option that has been shown to give patients the best chance of remission. However, some patients have GISTs that are unresectable or that have metastasized to other areas of the body. These patients have limited treatment options and the clinical outcome is generally poor.

THE-630 is a pan-variant receptor tyrosine kinase (KIT) inhibitor that can inhibit all known, clinically relevant mutations of the KIT protein. It can therefore be useful for patients who have developed resistance to earlier lines of therapy by accruing mutations.

Preclinical studies have shown that THE-630 can inhibit all major classes of KIT-activating and resistance mutations in GIST. The phase 1/2 trial will assess the safety, efficacy, and pharmacokinetics of THE-630 in an estimated 160 patients with advanced GIST, aged 18 years and older.

The study will have a dose-escalation phase to determine the safety profile of the treatment and an expansion phase to evaluate its antitumor activity. The trial is estimated to be completed in June 2026.


Theseus Pharmaceuticals announces first patient treated with THE-630 in phase 1/2 study in patients with advanced gastrointestinal stromal tumors (GIST). News release. Theseus; January 10, 2022.

A study of THE-630 in patients with advanced gastrointestinal stromal tumors (GIST). US National Library of Medicine. Updated December 27, 2021. Accessed January 22, 2022.