カペシタビン

用途生体内で 5- フルオロウラシ ルへと代謝されて DNA 合成阻害作用を示し ます。

用途カペシタビン（Capecitabine）とは、フッ化ピリミジン系代謝拮抗剤に類する抗悪性腫瘍剤（抗がん剤）。 フッ化ピリミジン系抗悪性腫瘍剤の代表ともいえるフルオロウラシル（5-FU）は、これまで乳癌や消化器癌の治療に最も多く使われてきた抗がん剤の一つであるが、カペシタビンは、骨髄細胞や消化管では活性体になりにくく腫瘍組織内でより選択的に5-FUを生成することを目的として、日本ロシュ研究所（現中外製薬株式会社鎌倉研究所）で創製された。

説明Capecitabine is a new oral fluoropyrimidine carbamate for patients with advanced neoplastic disease, approved as Xeloda for the treatment of refractory metastatic breast cancer after failure on Paclitaxel and an anthracycline-based chemotherapy regimen ; it is a prodrug of doxifluridine (5-fluorouracil ; 5-FU) activated by a cascade of 3 enzymes concentrated in human liver and cancer tissue, resulting in the selective release of 5-FU at the tumor site and offering a prolonged tumour exposure to 5-FU. Oral Capecitabine passes intact through the intestinal mucosa, is converted first by carboxylesterase to 5'-deoxy-5- fluorocytidine in the liver, then by cytidine deaminase to 5'-deoxy-5-fluorouridine in the liver and tumour tissues and finally by thymidine phosphorylase to 5-FU in tumors. Therefore, Xeloda is much safer and more effective than 5-FU (for example, in the HCT116 human colon cancer and the MX-1 breast cancer xenograft .models).

使用Capecitabine is an antineoplastic agent. Capecitabine is a prodrug of Doxifluridine (D556750).

一般的な説明The drug is available in a 150- and 500-mg tablets for oraluse. This drug is a fluoropyrimidine carbamate prodrugform of 5-fluorouracil (5-FU). It is used to treat breast cancerand colorectal cancer. The drug is converted to 5-FU bythe enzyme thymidine phosphorylase following esterase activity to hydrolyze the carbamate moiety and deamination.Capecitabine is readily absorbed by the GI tract, and peakplasma levels of 5-FU occur about 2 hours after oral administration.Indications, drug interactions, and toxicities areequivalent to those of 5-FU.