Aspirin reduces adverse effects of gefitinib.

We measured serum levels of soluble (s) P-selectin and thromboxane B 2 (TxB 2 ) in patients with lung cancer treated with gefitinib, and investigated the effect of low-dose aspirin on some adverse effects of gefitinib. The serum levels of sP-selectin and TxB 2 increased significantly in all patients who received gefitinib for 2 weeks. Forty patients were recruited, and 28 received gefitinib without low-dose aspirin (Group 1) and 12 were co-administered low-dose aspirin (Group 2). In Group 2, the frequency of adverse events, skin rash and diarrhea was evidently reduced by the low-dose aspirin therapy, despite having shown no remarkable change in gefitinib responsiveness between both groups. In one of the 12 patients in Group 2, aspirin therapy was suspended due to the occurrence of nasal bleeding. Four days after treatment suspension, she developed a skin lesion in her finger. However, the skin lesion improved after re-administration of aspirin without any other medications. After treatment, TxB 2 significantly decreased, but not sP-selectin. These results suggest that one of the mechanisms causing gefitinib-related adverse effects depends on platelet activation. Administration of gefitinib with low-dose aspirin to lung cancer patients may prevent the development of gefitinib-related complications.