Clinical Trial Details
— Status: Completed
Administrative data
NCT number |
NCT03156036 |
Other study ID # |
TemoCap2 |
Secondary ID |
|
Status |
Completed |
Phase |
Phase 2
|
First received |
|
Last updated |
|
Start date |
November 30, 2017 |
Est. completion date |
February 2, 2021 |
Study information
Verified date |
September 2023 |
Source |
Asan Medical Center |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Interventional
|
Clinical Trial Summary
This is a prospective biomarker-stratified, randomised phase II study of preoperative CRT
with temozolomide plus capecitabine in patients with locally advanced rectal cancer.
The primary endpoint is pathologic complete response rates defined as total regression of the
primary tumor.
For each cohort of MGMT hypermethylated versus MGMT unmethylated, patients will be randomised
(ratio 1:1 for each arm) into preoperative CRT with capecitabine or preoperative CRT with
temozolomide plus capecitabine arms. According to the prior phase I results, MGMT
hypermethylated arm is estimated as 70% of total patients and the target pathologic complete
response rate was assumed as 35% in this population when treated with preoperative CRT with
temozolomide and capecitabine (15% in the standard treatment arm or those with unmethylated
MGMT). Investigator would like to demonstrate the superiority in terms of pathologic complete
responses when treated with preoperative CRT with temozolomide plus capecitabine in patients
with locally advanced rectal cancer, and to validate the predictive role of MGMT status
Description:
Preoperative chemoradiation (CRT) with fluoropyrimidine (5-fluorouracil or capecitabine) is
now regarded as a standard treatment option in patients with locally advanced resectable
rectal cancer and pathologic response rates and tumor regression grades after preoperative
CRT have been proved to be important prognostic factors for survival outcomes.
Several studies of preoperative CRT with fluoropyrimidines plus other agents, such as
oxaliplatin, irinotecan, cetuximab, and bevacizumab, have been performed to improve
pathologic response rates; however, they have failed to show improved results compared to
those with fluoropyrimidine alone.
Thus fluoropyrimidine alone is a standard chemotherapeutic strategy in patients with locally
advanced resectable rectal cancer who will be treated with preoperative CRT at present.
Temozolomide is an oral alkylating agent, and has been proved to be effective in patients
with glioblastoma or high grade anaplastic glioma when administered with concurrent
radiotherapy either as adjuvant or recurrent settings.
Temozolomide has been known to deplete O6-methylguanine DNA methyltransferase (MGMT), which
is one of the DNA repair enzymes, and recent studies have shown that MGMT gene silencing
(lower expression by immunohistochemistry or hypermethylation by methylation-specific PCR)
played a predictive marker of better responses to CRT with temozolomide in patient with
glioblastoma and high grade anaplastic glioma.
Silencing of MGMT by promoter hypermethylation has been known to involve colorectal
carcinogenesis pathway by the association with KRAS mutation and low-CIMP (CpG island
methylation phenotype), and microsatellite instability. There have been suggestions that MGMT
promoter hypermethylation played a role as a predictive factor of low recurrence in
colorectal cancer patients with adjuvant oral fluoropyrimidine chemotherapy after curative
surgery, and also as a predictive factor for treatment response from temozolomide in patients
with metastatic colorectal cancer.
Therefore, combination chemotherapy of temozolomide plus capecitabine for rectal cancer
patients when treated with preoperative CRT is worthy of investigated especially in those
harbouring silenced MGMT gene as following reasons;
1. the role of temozolomide has been well established,
2. MGMT gene silencing is associated with colorectal carcinogenesis and might act as a
predictive biomarker; and
3. the addition of temozolomide can be synergistic during preoperative CRT with
capecitabine for rectal cancer patients.
Investigator have performed a phase I study of preoperative CRT with temozolomide plus
capecitabine in patient with locally advanced rectal cancer, and the results of this study
has been published The recommended dose of temozolomide was determined as 75 mg/m2 once daily
when combined with standard preoperative CRT with capecitabine, there was no grade 4 adverse
events and the treatment was generally well tolerated. MGMT hypermethylation was found in 72%
of rectal cancer patients (16/22), and the pathologic complete responses rates were 37.5%
(6/16) in patient harbouring hypermethylated MGMT versus 16.7% in those with unmethylated
MGMT.
On the basis of prior trial results, Investigator concluded that preoperative CRT with
temozolomide plus capecitabine is well tolerated without any notable adverse event, and is
worthy of investigation especially in those harbouring MGMT gene silencing.
Investigator planned a prospective, biomarker-stratified, randomised phase II study of
preoperative CRT with temozolomide plus capecitabine in patients with locally advanced rectal
cancer to demonstrate the addition of temozolomide in the conventional preoperative CRT might
enhance the pathologic responses in those harbouring hypermethylated MGMT.