A Phase 1 interventional study of IDRX-42 in Gastrointestinal Neoplasms, Gastrointestinal Stromal Tumor (GIST) and Digestive System Disease, sponsored by IDRX, Inc., a wholly owned subsidiary of GSK, LLC. Active, not recruiting at 31 sites in 11 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-05.
Sponsored by IDRX, Inc., a wholly owned subsidiary of GSK, LLC · Phase 1, Interventional, and Treatment
This is the first clinical trial of IDRX-42. The study is designed to evaluate the safety, tolerability, PK, and preliminary antitumor activity of IDRX-42 in adult participants with advanced (metastatic and/or surgically unresectable) GIST.
This is a Phase 1/1b open-label, first-in-human FIH study of IDRX-42, an orally administered small molecule tyrosine kinase inhibitor. Eligible participants will have metastatic and/or surgically unresectable GIST. The study consists of 2 parts. Phase 1 comprises dose escalation to assess clinical and pharmacologic profile and safety/tolerability after failure of at least prior imatinib and support choice of the recommended phase 1b dose(s) and schedule(s) (RP1bDs)). Phase 1b expansion will enroll separate cohorts of participants defined by numbers of lines of prior GIST therapy at the selected RP1bD(s) to assess the preliminary antitumor effect of IDRX-42 and further characterize the safety profile of IDRX-42 at the RP1bD(s). In addition, a Concentration-QTc (C-QTc) substudy will be conducted in a subset of participants enrolled at selected sites in the study to characterize the effects of IDRX-42 on QTc and other ECG parameters in GIST patients.
779 studies on the registry are indexed under Gastrointestinal Neoplasms; 230 are open to participants now.
This study's enrollment of 276 is above the median of 61 across 568 interventional studies indexed under Gastrointestinal Neoplasms.
Browse Gastrointestinal Neoplasms studies →This is the only study on the registry with IDRX, Inc., a wholly owned subsidiary of GSK, LLC as lead sponsor.
Counted across the registry records on this site, refreshed daily.
Phase 1
Additional for Phase 1b Exploratory Cohorts
Exclusion Criteria:
Participants should have advanced (metastatic and/or surgically unresectable) GIST, following failure of at least prior imatinib therapy due to progression of GIST.
Drug: IDRX-42
Participants with advanced GIST who have had GIST progression after first-line imatinib only (second line therapy setting) and refused or are ineligible for other standard of care (SOC) therapies.
Drug: IDRX-42
Participants with metastatic and/or surgically unresectable GIST following progression EITHER after sequential imatinib then sunitinib (third-line therapy setting) OR after imatinib, sunitinib, and then an additional TKI agent (i.e., regorafenib or ripretinib) (fourth-line therapy setting) OR after imatinib, sunitinib, regorafenib, and ripretinib (5th line or greater therapy).
Drug: IDRX-42
Participants with metastatic and/or surgically unresectable GIST who are treatment naïve (first line therapy) and refused or are ineligible for other standard of care (SOC) therapies.
Drug: IDRX-42
Participants with GIST progression who meet the same criteria as Cohort 2 (third line or greater TKI therapy) and have had prior treatment with investigational agents NB003 or THE-630 or a line of therapy of bezuclastinib plus sunitinib combination.
Drug: IDRX-42
Administered at assigned doses and schedules once or twice daily in continuous cycles of 28 days each.
Phase 1 (Dose Escalation) - Safety and Tolerability (Nature, incidence, and severity of any DLTs)
Time frame: When participant completes 1 cycle (28 days) treatment with safety and tolerability assessment by investigators
Phase 1 (Dose Escalation) - Safety and Tolerability (Nature, incidence, and severity of any DLTs)
Time frame: Approximately 18 months from first participant enrolled
Phase 1 (Dose Escalation) - Determination of the MTD and/or RP1bD(s) of orally administered IDRX-42
Time frame: Approximately 18 months from first participant enrolled
Phase 1 (Dose Escalation) - C-QTc sub-study: QTcF - concentration response analysis
Time frame: At the end of Cycle 1 Day 1 and at the end of Cycle 2 Day 1 (each cycle is 28 days)
Phase 1b-Number of participants with TEAEs and with laboratory test results
Time frame: Approximately 18 months
Phase 1b - Objective Response Rate (ORR) mRESIST v1.1
Time frame: Approximately 18 months
Phase 1b - C-QTcF sub-study: QTcF - concentration response analysis
Time frame: At the end of Cycle 1 Day 1 and at the end of Cycle 2 Day 1 (each cycle is 28 days)
Phase 1 (Dose Escalation)- Number of participants with non-DLT TEAEs and with laboratory test results
Time frame: 6 months
Phase 1 (Dose Escalation) - ORR per mRECIST v1.1
Time frame: 6 months
Phase 1 (Dose Escalation) - Cmax; Maximum Observed Concentration of IDRX-42
Time frame: At the end of Cycle 1 Day 1 and at the end of Cycle 2 Day 1 (each cycle is 28 days)
Phase 1 (Dose Escalation) - Tmax; Time of First Occurrence of Maximum Plasma Concentration (Cmax) of IDRX-42
Time frame: At the end of Cycle 1 Day 1 and at the end of Cycle 2 Day 1 (each cycle is 28 days)
Phase 1 (Dose Escalation) - AUC 0-24; Area Under the Concentration-time Curve from Time Zero to 24 hours for IDRX-42
Time frame: At the end of Cycle 1 Day 1 and at the end of Cycle 2 Day 1 (each cycle is 28 days)
Phase 1 (Dose Escalation) - Duration of response (DOR) per mRECIST v1.1
Time frame: 6 months
Phase 1 (Dose Escalation) - Time to response (TTR) per mRECIST v1.1
Time frame: 6 months
Phase 1 (Dose Escalation) - Progression-free survival (PFS), per mRECIST v1.1
Time frame: 6 months
Phase 1 (Dose Escalation) - C-QTcF sub-study: QTcF, heart rate, PR, QRS interval at baseline, post baseline and change from baseline.
Time frame: At the end of Cycle 1 Day 1 and at the end of Cycle 2 Day 1 (each cycle is 28 days)
Phase 1b- Duration of response (DOR) per mRECIST v1.1
Time frame: 18 months
Phase 1b - PFS per mRECIST v1.1
Time frame: 18 months
Phase 1b - Clinical benefit rate (CBR) per mRECIST v1.1
Time frame: 18 months
Phase 1b - TTR per mRECIST v1.1
Time frame: 18 months
Phase 1b - Cmax; Maximum Observed Concentration of IDRX-42
Time frame: At the end of Cycle 1 Day 1 and at the end of Cycle 2 Day 1 (each cycle is 28 days)
Phase 1b - Tmax; Time of First Occurrence of Maximum Plasma Concentration (Cmax) of IDRX-42
Time frame: At the end of Cycle 1 Day 1 and at the end of Cycle 2 Day 1 (each cycle is 28 days)
Phase 1b - AUC 0-24; Area Under the Concentration-time Curve from Time Zero to 24 hours for IDRX-42
Time frame: At the end of Cycle 1 Day 1 and at the end of Cycle 2 Day 1 (each cycle is 28 days)
Phase 1b - Overall survival
Time frame: 18 months
Phase 1b C-QTc sub-study: QTcF, heart rate, PR, QRS interval at baseline, post baseline and change from baseline.
Time frame: At the end of Cycle 1 Day 1 and at the end of Cycle 2 Day 1 (each cycle is 28 days)
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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