Preoperative Chemoradiation With Capecitabine Plus Temozolomide in Patients With Locally Advanced Resectable Rectal Cancer: Phase I Study
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; further studies are needed to find effective combination for
improving pathologic responses other than fluoropyrimidines alone in these patient
population.
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, and also seemed to be effective in
patients with malignant melanoma either as monotherapy or combination chemotherapy.
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 lower expression (by
immunohistochemistry) or hypermethylation (by methylation-specific PCR) of MGMT could be a
predictive marker of better responses to treatment with temozolomide in patient with
glioblastoma, high grade anaplastic glioma or malignant melanoma.
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 hypermethylation of MGMT promoter could be detected in 29% to
46% of tumor tissues from sporadic colorectal cancer patients. Nagasaka et al. showed
notable results that MGMT promoter methylation status was associated with microsatellite
instability and hypermethylation of MGMT promoter could be a predictive factor of low
recurrence in colorectal cancer patients with adjuvant oral fluoropyrimidine chemotherapy
after curative surgery. In addition, Shacham-Shmueli et al. showed that temozolomide could
be an additional treatment option in a small group of patients with chemotherapy-refractory
metastatic colorectal cancer which had lower MGMT expressions.
Interventional
Endpoint Classification: Safety/Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Treatment
Maximum tolerated dose (MTD)
The MTD is defined as the maximum dose level in the doses of temozolomide tested with capecitabine and radiation in which the incidence proportion of DLT exceeds 30%.
5-6 weeks during study treatment
Yes
Tae Won Kim, Professor
Principal Investigator
Asan Medical Center
Korea: Food and Drug Administration
ML28381
NCT01781403
April 2013
March 2016
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