Raltitrexed: current clinical status and future directions

Raltitrexed ('Tomudex') monotherapy is a conveniently administered alternative to 5-fluorouracil (5-FU) in the first-line treatment of advanced colorectal cancer (CRC), and has single-agent activity in a variety of advanced solid tumours. Although both raltitrexed and 5-FU are thymidylate synthase inhibitors, raltitrexed has a specific mode of action and a toxicity profile distinct from 5-FU. The mechanism of action of raltitrexed is also completely different from that of oxaliplatin, irinotecan and other drugs with which it has been combined. These properties, together with preclinical data, suggested that combinations of raltitrexed with 5-FU, other chemotherapeutic agents, or radiotherapy could result in improved therapies for a variety of advanced solid tumours, including advanced CRC. This review outlines the appropriate management of patients treated with raltitrexed, whether as monotherapy or in combination, and discusses the preliminary results of combination studies with raltitrexed in a range of tumour types including advanced CRC, malignant mesothelioma, gastric, pancreatic, head and neck, and non-small-cell lung cancers. Of particular interest is the combination of raltitrexed and oxaliplatin, which has shown promising antitumour effects in first-line treatment of advanced CRC and malignant mesothelioma, a disease that is refractory to chemotherapy.