Oxaliplatin: a review of its use in combination therapy for advanced metastatic colorectal cancer.

UNLABELLED: Oxaliplatin (Eloxatin) is the only platinum compound to show clinical activity in colorectal cancer. The efficacy of a combination of oxaliplatin with various schedules of fluorouracil (5-FU)/folinic acid (FA) as first- or second-line treatment for advanced metastatic colorectal cancer has been investigated in large phase III trials. FOLFOX4 (an oxaliplatin/5-FU/FA regimen) as first-line therapy (n = 795) was superior to irinotecan/5-FU/FA (IFL). Response rates were 45% vs 31%, and median progression-free survival duration was 8.7 vs 6.9 months. The survival advantage shown by FOLFOX4 over the irinotecan combination (median survival duration 19.5 vs 14.8 months) may be confounded by differences in post-study treatment but equivalent efficacy is supported by another phase III trial of oxaliplatin and irinotecan combinations. As first-line therapy, oxaliplatin added to various 5-FU/FA regimens more than doubled the response rates from 16-22.6% to 48.3-53% and the median duration of progression-free survival was significantly longer with oxaliplatin/5-FU/FA than 5-FU/FA alone (7.9-9 versus 5.3-6.2 months, respectively). In disease resistant to irinotecan-based therapies, the oxaliplatin (FOLFOX4) regimen had superior efficacy to 5-FU/FA alone in a pivotal phase III trial (n = 816). Response rates and median durations of progression-free survival were 9.6% vs 0.7% and 5.6 vs 2.6 months, respectively. An oxaliplatin-induced cumulative peripheral sensory neuropathy (evident when total dose reaches approximate, equals 800 mg/m(2)) is dose limiting. The most frequently occurring grade 3 or 4 toxicities in oxaliplatin/5-FU/FA-recipients were neutropenia (up to 48%) and neurological toxicities (up to 18%). Gastrointestinal effects (diarrhoea [ approximate, equals 12%], nausea, vomiting, or mucositis/stomatitis [up to 6%]) are manageable. Withdrawals from oxaliplatin treatment were due to neuropathy (up to 10%), diarrhoea and/or vomiting (1%) or cutaneous toxicity (1%).
CONCLUSION: As first-line therapy for metastatic colorectal cancer, oxaliplatin with 5-FU/FA consistently improves response rates and progression-free survival compared with various regimens of 5-FU/FA alone. The significant survival advantage shown by oxaliplatin/5-FU/FA (FOLFOX4) compared with first-line therapy with irinotecan/5-FU/FA (IFL) is encouraging but may require further confirmation. Oxaliplatin/5-FU/FA produces a significantly higher response rate and longer progression-free survival than 5-FU/FA in patients failing irinotecan-based therapies, and as such is also a useful second-line treatment. Although cumulative neurotoxicity is dose limiting, oxaliplatin has a manageable tolerability profile. Oxaliplatin as first- or second-line therapy is a valuable addition to the limited, but expanding, armamentarium of cytotoxic agents useful in advanced metastatic colorectal cancer.