A Phase 1/2 interventional study of varsetatug masetecan and bevacizumab + 5-FU + leucovorin in Colo-rectal Cancer, sponsored by CytomX Therapeutics. Not yet recruiting. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-28.
Sponsored by CytomX Therapeutics · Phase 1/2, Interventional, and Treatment
This is a non-registrational Phase 1/2, multicenter, open-label trial to evaluate the efficacy and safety of varsetatug masetecan combined with anti-cancer therapies in participants with unresectable metastatic colorectal cancer in the second line treatment setting.
The study is comprised of 2 parts. Part 1 (Phase 1) involves varsetatug masetecan dose finding to identify the recommended Phase 2 dose (RP2D) of varsetatug masetecan in combination with bevacizumab + 5-FU + leucovorin in the second line treatment setting. Part 2 (Phase 2) will further assess safety, tolerability and antitumor activity doses and schedules of varsetatug masetecan in combination with bevacizumab + 5-FU + leucovorin in this second line patient population, based on the dose finding results from Part 1 of this trial. In addition, Part 2 will also further evaluate dose and schedules of varsetatug masetecan in combination with bevacizumab (without 5-FU and leucovorin) in the second line treatment setting based on the dose finding results in the ongoing Phase 1 Study CTMX-2051-101 assessing the varsetatug masetecan combination with bevacizumab (NCT06265688).
2,457 studies on the registry are indexed under Colonic Neoplasms; 458 are open to participants now.
This study's planned enrollment of 368 is above the median of 75 across 1,711 interventional studies indexed under Colonic Neoplasms.
Browse Colonic Neoplasms studies →CytomX Therapeutics is the lead sponsor of 10 studies on the registry; 3 are open to participants now.
Of its 6 completed or terminated interventional studies of FDA-regulated products, 3 (50%) have results posted.
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.
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.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
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.
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.
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.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
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.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
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.
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.
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.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Drug: varsetatug masetecan · Drug: bevacizumab + 5-FU + leucovorin
Drug: varsetatug masetecan · Drug: bevacizumab
Investigational Product
Drug pages: Bevacizumab · Fluorouracil · Leucovorin
IV infusion
IV infusion
Also known as: Avastin
Part 1 - Safety and tolerability of varsetatug masetecan in combination with bevacizumab + 5-FU + leucovorin
The number of participants experiencing a dose-limiting toxicity (DLT) as defined in the protocol, AEs (adverse events), and treatment-emergent adverse events (TEAEs) at any dose level
Time frame: 27 months
Part 2 - Progression-free survival (PFS) based on blinded independent central review (BICR)
PFS defined as the time from participant allocation to a trial intervention to the first documentation of objective disease progression, as determined by BICR according to Response Evaluation Criteria in Solid Tumors (RECIST) v1.1, or death due to any cause, whichever occurs first
Time frame: 27 months
Objective Response Rate (ORR)
ORR defined as the proportion of participants with a complete response (CR) or partial response (PR), as determined by BICR and Investigator assessment according to RECIST v1.
Time frame: 27 months
Disease Control Rate (DCR)
DCR defined as the proportion of participants with confirmed CR, PR, or stable disease (SD), as determined by BICR and Investigator assessment according to RECIST v1.1
Time frame: 27 months
PFS based on Investigator assessment
PFS defined as the time from participant allocation to a trial intervention to the first documentation of objective disease progression, as determined by Investigator assessment according to RECIST v1.1, or death due to any cause, whichever occurs first
Time frame: 27 months
Overall Survival (OS)
OS defined as the time from participant allocation to a trial intervention to death due to any cause
Time frame: 27 months
Duration of Response (DOR)
DOR for participants with a confirmed CR or PR, is defined as the time from the first occurrence of a documented objective response to disease progression or death due to any cause (whichever occurs first), as determined by BICR and Investigator assessment according to RECIST v1.1
Time frame: 27 months
Duration of Disease Control (DODC)
DODC for participants with a confirmed CR, PR, or SD, is defined as the time from the first occurrence of a documented CR, PR, or SD to disease progression or death due to any cause (whichever occurs first), as determined by BICR and Investigator assessment according to RECIST v1.1
Time frame: 27 months
No study locations are listed for this record.
Plan to share: No
No publications or documents are linked to this record.
Start is estimated for Dec 2026; primary completion for Feb 2029, 26 months later.
Of 60 phase 1/2 interventional studies under Colonic Neoplasms, half reached primary completion within 65 months of starting (the median), counting those still running; a quarter within 41 and three quarters within 93. This study's planned 26 months is below that.
How these figures are worked out, and which studies are left out of them.
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 ↗
This study is not yet recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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CytomX Therapeutics