A Phase 1 interventional study of Pimitespib and Imatinib in Gastrointestinal Stromal Tumors, sponsored by Taiho Pharmaceutical Co., Ltd.. Active, not recruiting at 14 sites in 5 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-01-20.
Sponsored by Taiho Pharmaceutical Co., Ltd. (part of Otsuka Holdings Co., Ltd.) · Phase 1, Interventional, and Treatment
This study consists of Dose escalation part and Expansion part. In Dose Escalation Part, the maximum tolerated dose of combination of pimitespib and imatinib in patients with gastrointestinal stromal tumors (GIST) who are judged to be refractory to imatinib, estimate the recommended dose, evaluate safety and pharmacokinetics, and observe the antitumor effect. Expansion part consists of 3 arms. In Arm A, the efficacy and safety will be evaluated, which of the combination of pimitespib and imatinib in patients with GIST who have failed imatinib at doses below the MTD determined in Dose Escalation Part. In Arm B, the efficacy and safety of pimitespib monotherapy will be evaluated and the therapeutic effect of imatinib administration after pimitespib will be evaluated in an exploratory manner. In Arm C, the efficacy and safety of sunitinib monotherapy will be evaluated as reference data.
343 studies on the registry are indexed under Gastrointestinal Stromal Tumors; 61 are open to participants now.
This study's planned enrollment of 78 is above the median of 50 across 252 interventional studies indexed under Gastrointestinal Stromal Tumors.
Browse Gastrointestinal Stromal Tumors studies →Taiho Pharmaceutical Co., Ltd. is the lead sponsor of 43 studies on the registry; 4 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
The standard rules for measuring tumours on CT or MRI scans, to tell whether a cancer is shrinking, stable or growing during treatment.
“Measurable disease per RECIST 1.1” usually means at least one tumour 10 mm or more at its longest on a CT scan, or a lymph node 15 mm or more across its short axis.
The amount of disease can be tracked with a defined measurement, so the study can see whether it shrinks or grows. It might be a tumour measured on a scan or, in some blood cancers such as myeloma, a marker measured in blood or urine.
The criteria or the study team say which measurement counts — having no tumour visible on a scan does not by itself rule you out.
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
A line of therapy is one course of treatment, which may combine several drugs. First-line is the first course given; second-line follows when that stops working or is not tolerated.
“Two prior lines” means two courses that count separately under the study’s rules — not simply two drugs. Ask the study team if you are unsure how yours are counted.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Histologically or cytologically confirmed
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
RECIST
The standard rules for measuring tumours on CT or MRI scans, to tell whether a cancer is shrinking, stable or growing during treatment.
“Measurable disease per RECIST 1.1” usually means at least one tumour 10 mm or more at its longest on a CT scan, or a lymph node 15 mm or more across its short axis.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Measurable disease
The amount of disease can be tracked with a defined measurement, so the study can see whether it shrinks or grows. It might be a tumour measured on a scan or, in some blood cancers such as myeloma, a marker measured in blood or urine.
The criteria or the study team say which measurement counts — having no tumour visible on a scan does not by itself rule you out.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECOG performance status
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Line of therapy
A line of therapy is one course of treatment, which may combine several drugs. First-line is the first course given; second-line follows when that stops working or is not tolerated.
“Two prior lines” means two courses that count separately under the study’s rules — not simply two drugs. Ask the study team if you are unsure how yours are counted.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Pimitespib in combination with imatinib
Drug: Pimitespib · Drug: Imatinib
Pimitespib in combination with imatinib
Drug: Pimitespib · Drug: Imatinib
Pimitespib followed by imatinib
Drug: Pimitespib · Drug: Imatinib
Sunitinib
Drug: Sunitinib
Pimitespib will be administered orally in 5 consecutive days followed by 2 days off treatment (QD 5) on an empty stomach at least 1 hour before or 2 hours after a meal. The doses in the Dose Escalation Part will be 80, 120 (starting dose), and 160 mg. The doses used in Arm A will be MTD or recommended dose (RD) based on the information, including the safety and the pharmacokinetics (PK) data in the Dose Escalation Part. In Expansion Part-B, pimitespib will be administered with the starting dose of 160 mg daily.
Also known as: TAS-116
Imatinib will be administered orally, after a meal and large glass of water QD. The doses in Dose Escalation Part will be 400 mg or 300 mg (De-escalation). The doses used in Expansion Part-A will be MTD or RD based on information, including the safety and PK data in the Dose Escalation Part. In Expansion Part-B, imatinib will be administered post after pimitespib discontinuation with the starting dose of 400 mg daily.
Sunitinib will be administered orally QD with a starting dose of 50 mg, on a schedule of 4 weeks on treatment followed by 2 weeks off, and will be taken with or without a meal in Expansion Part-C.
Dose-limiting toxicity (DLT) of pimitespib in combination with imatinib
Time frame: At the end of Cycle 1 (each cycle is 28 days)
Maximum tolerable dose (MTD) of pimitespib in combination with imatinib
Time frame: At the end of Cycle 1 (each cycle is 28 days)
Progression-free survival (PFS)
Time frame: approximately 2 years
Overall survival (OS)
Time frame: approximately 2 years
Overall response rate (ORR)
Time frame: approximately 2 years
Disease control rate (DCR)
Time frame: approximately 2 years
Duration of response (DoR)
Time frame: approximately 2 years
Adverse event (AE)
Time frame: approximately 2 years
Adverse drug reaction (ADR)
Time frame: approximately 2 years
Maximum plasma concentration (Cmax)
Time frame: Multiple time points on Day 1 and Day5 or Day12 of Cycle 1 (each cycle is 28 days)
Time to reach maximum plasma concentration (Tmax)
Time frame: Multiple time points on Day 1 and Day5 or Day12 of Cycle 1 (each cycle is 28 days)
Under the plasma concentration-time curve up to the last observable concentration (AUC0-last)
Time frame: Multiple time points on Day 1 and Day5 or Day12 of Cycle 1 (each cycle is 28 days)
Area under the plasma concentration-time curve from time 0 to infinity (AUC0-inf)
Time frame: Multiple time points on Day 1 and Day5 or Day12 of Cycle 1 (each cycle is 28 days)
λz
Time frame: Multiple time points on Day 1 and Day5 or Day12 of Cycle 1 (each cycle is 28 days)
Half-life (T1/2)
Time frame: Multiple time points on Day 1 and Day5 or Day12 of Cycle 1 (each cycle is 28 days)
Oral clearance (CL/F)
Time frame: Multiple time points on Day 1 and Day5 or Day12 of Cycle 1 (each cycle is 28 days)
Apparent volume of distribution (Vz/F)
Time frame: Multiple time points on Day 1 and Day5 or Day12 of Cycle 1 (each cycle is 28 days)
Mean residence time (MRT)
Time frame: Multiple time points on Day 1 and Day5 or Day12 of Cycle 1 (each cycle is 28 days)
Accumulation ratio
Time frame: Multiple time points on Day 1 and Day5 or Day12 of Cycle 1 (each cycle is 28 days)
Metabolite ratio
Time frame: Multiple time points on Day 1 and Day5 or Day12 of Cycle 1 (each cycle is 28 days)
Plan to share: Yes — Taiho provides a platform for accepting researchers' requests for sharing anonymized, patient-level, analyzable datasets from articles published in peer-reviewed journals about the primary results from Taiho-sponsored interventional clinical trials in patients in which the medicine and the indication has received marketing approval from regulatory authorities in the United States, the European Union, and/or Japan on or after January 15, 2018.
Supporting information: Study protocol, Statistical analysis plan
Time frame: https://www.taiho.co.jp/en/science/policy/clinical_trial_information_disclosure_policy/index.html
Access criteria: Access to the clinical trial data is contingent upon approval of a proposed study protocol by an independent review panel and the execution of a data-sharing agreement with the researcher.
Data sharing details ↗ · vivli.org
No publications or documents are linked to this record.
This study is active, not recruiting, as verified in Jan 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drugs tested here: Pimitespib · Sunitinib
Gastrointestinal Stromal Tumors →
Taiho Pharmaceutical Co., Ltd. →