Reduction of cisplatin dosage by ZD 1839

Cisplatin (CDDP) is the main chemotherapeutic drug in the treatment of recurrent or metastatic squamous cell carcinoma of the head and neck (SCCHN), but its nephrotoxicity often limits the treatment. ZD 1839 is an orally-applicable, selective EGFR tyrosine kinase inhibitor. This investigation explored whether the cisplatin dose can be reduced by the additional application of ZD 1839. Four different SCCHN cell lines were treated with descending doses of CDDP alone or in combination with ZD 1839. Proliferation was measured by the MTT assay; tumor cell toxicity was measured by using the lactate dehydrogenase approach. ZD 1839 augments CDDP-dependent antiproliferative effects. By adding ZD 1839 to the treatment regimen, the CDDP dose could be reduced by up to 25% of the CDDP IC50 dose without compromising the antiproliferative effect. Adding ZD 1839 to CDDP may therefore enable CDDP treatment at a lower dose without compromising antiproliferative effects.