NEW YORK – Theseus Pharmaceuticals said Thursday that it anticipates progress in three precision oncology programs in 2023 and early 2024, including preliminary data from its Phase I/II trial of THE-630 in gastrointestinal stromal tumors as well as an investigational new drug application filing and introduction of a new candidate.
The Cambridge, Massachusetts-based company is developing THE-630 as a fifth-line treatment for advanced, KIT-driven GIST where no standard therapies are available, with plans to later move into second-line GIST. THE-630 is an inhibitor of the receptor tyrosine kinase KIT that is effective against both cancer driver and resistance mutations in KIT. According to Theseus, current standard-of-care treatments in GIST do not inhibit all of those mutations, leading to potential treatment resistance and emergence of heterogeneous clonal tumors.
The first part of the ongoing Phase I/II trial is a dose escalation study, which is to be followed by an expansion phase. Patients in the trial must have disease progression on imatinib or be intolerant to it and must have also received one of several other therapies. Theseus expects to present preliminary safety, pharmacokinetic, and activity data from the trial alongside an analysis of circulating tumor DNA in the second quarter of 2023, with follow-up data from additional cohorts in the fourth quarter.
The company also announced its plans to file an investigational new drug application with the US Food and Drug Administration for its EGFR tyrosine kinase inhibitor THE-349 in the fourth quarter of 2023. THE-349 has shown activity against multiple EGFR mutations, including T790M and C797X, found in tumors from patients with non-small cell lung cancer who are resistant to osimertinib. Theseus said it plans to pursue registration of the drug as a monotherapy in that setting and investigate combination therapy opportunities.
Lastly, Theseus introduced a new tyrosine kinase inhibitor program targeting BCR-ABL for patients with relapsed or refractory chronic myeloid leukemia with the T315I mutation and newly diagnosed Philadelphia chromosome-positive acute lymphoblastic leukemia. It expects to nominate a candidate for the program by early 2024.