This phase II trial studies how well CBX-12 works in treating patients with microsatellite stable colorectal cancer that has spread to other parts of the body (metastatic) and is no longer responding to chemotherapy treatment (chemotherapy-refractory). The usual approach to treating colorectal cancer includes treatment with surgery, radiation, or Food and Drug Administration (FDA)-approved drugs such as trifluridine-tipiracil, bevacizumab, regorafenib, or fruquintinib. However, most metastatic colorectal patients progress through all approved treatments and eventually succumb to their disease. CBX-12 is a drug that contains a peptide (a substance that contains many amino acids \[molecules that join together to form proteins\]) called pHLIP, linked to an anticancer substance called exatecan. Upon administration, pHLIP gets inserted into the cellular membrane of tumor cells, delivering exatecan to kill them. Giving CBX-12 may work better than the usual approach in treating patients with metastatic chemotherapy-refractory microsatellite stable colorectal cancer.
PRIMARY OBJECTIVE: I. To determine the clinical activity, as determined by response rate, of pH low insertion peptide-exatecan conjugate CBX-12 (CBX-12) in microsatellite stable/mismatch repair proficient (MSS/pMMR) metastatic colorectal cancer (mCRC) patients. SECONDARY OBJECTIVES: I. To evaluate the pharmacodynamics of CBX-12 (DDR3 and apoptosis). II. To determine the effect of CBX-12 on progression-free survival (PFS). EXPLORATORY OBJECTIVES: I. To evaluate the tissue and plasma pharmacokinetics (PK) of CBX-12 and free exatecan. II. To evaluate circulating tumor deoxyribonucleic acid (DNA) (ctDNA) as a predictor for treatment response to CBX-12. III. To evaluate the safety and tolerability of CBX-12 dosed every 21 days. IV. To evaluate biomarkers of response to CBX-12 (DNA damage response, apoptosis, SLFN11 expression, TOP1-DNA complex). OUTLINE: Patients receive CXB-12 intravenously (IV) over 60 minutes on day 1 of each cycle. Cycles repeat every 21 days in the absence of disease progression or unacceptable toxicity. Additionally, patients undergo x-rays during screening, and computed tomography (CT), magnetic resonance imaging (MRI), and blood collection throughout the study and patients may undergo biopsy during screening and on study. After completion of study treatment, patients are followed up at 30 days and then every 3 months for 12 months or until death.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Undergo biopsy
Undergo blood sample collection
Undergo CT scan
Undergo MRI
Undergo chest x-rays
UCI Health - Chao Family Comprehensive Cancer Center and Ambulatory Care
Irvine, California, United States
USC / Norris Comprehensive Cancer Center
Los Angeles, California, United States
UC Irvine Health/Chao Family Comprehensive Cancer Center
Orange, California, United States
University of Florida Health Science Center - Gainesville
Gainesville, Florida, United States
Northwestern University
Chicago, Illinois, United States
Johns Hopkins University/Sidney Kimmel Cancer Center
Baltimore, Maryland, United States
Montefiore Medical Center-Einstein Campus
The Bronx, New York, United States
University of Cincinnati Cancer Center-UC Medical Center
Cincinnati, Ohio, United States
Ohio State University Comprehensive Cancer Center
Columbus, Ohio, United States
University of Cincinnati Cancer Center-West Chester
West Chester, Ohio, United States
...and 5 more locations
Objective response rate (ORR)
Treatment response will be assessed using Response Evaluation Criteria in Solid Tumors version 1.1. Objective response will be defined as either complete response or partial response. Simon's 2-stage optimal design will be used.
Time frame: From registration to disease progression or death due to any cause, assessed up to 12 months
Dose limiting toxicities (DLTs)
DLTs will be defined as any grade \>= 3 non-hematologic toxicity irrespective of adequate supportive treatment, or grade \>= 4 hematologic toxicity per Common Terminology Criteria for Adverse Events version 5.0 attributed as possibly, probably, or definitely related to drug. The ORR will be estimated along with the 95% confidence interval.
Time frame: Baseline up to 12 months
Pharmacodynamics of CBX-12 by DDR3 and apoptosis
Percent of tumor cells positive for deoxyribonucleic acid (DNA) damage marker γH2AX and percent of tumor cells positive for apoptosis marker cleaved caspase 3. Pre- and on-treatment comparisons will be made within patients who provide evaluable paired biopsies, using a paired t-test. A nonparametric method will be pursued as needed. Assuming an 80% evaluable biopsy rate out of 17 patients, we would obtain 14 evaluable pre-treatment and 14 evaluable post-treatment biopsies. Using a one-sided paired t-test at a type I error rate of 0.05, this study achieves 80% power to detect a mean paired difference of 0.6 standard deviation of differences, which is deemed to be a medium effect size (Cohen, 1992). In addition, will fit a logistic regression on objective response with increase in %γH2AX-positive tumor cells and increase in %caspase 3-positive tumor cells, separately as well as simultaneously.
Time frame: Baseline to 12 months
Progression-free survival (PFS)
PFS and OS will be estimated by the Kaplan-Meier method, along with 95% confidence regions. The median time will be estimated and compared with 5.6 months of PFS and 10.8 months (Prager et al., 2023). One-sample log-rank tests will be performed against the reference curves from Prager et al. (Prager et al., 2023).
Time frame: From registration to disease progression or death due to any cause, assessed up to 12 months
Overall survival (OS)
PFS and OS will be estimated by the Kaplan-Meier method, along with 95% confidence regions. The median time will be estimated and compared with 5.6 months of PFS and 10.8 months (Prager et al., 2023). One-sample log-rank tests will be performed against the reference curves from Prager et al. (Prager et al., 2023).
Time frame: From registration to disease progression or death due to any cause, assessed up to 12 months
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.