The onset of drug-associated ILD during therapy for advanced NSCLC usually occurs within a few weeks of the start of treatment (Thomas et al, 2000; Gupta et al, 2002; Kudrik et al, 2002; Read et al, 2002) . Indeed, retrospective analysis of the first 152 patients in Japan to experience gefitinib-associated ILD showed that 475% of cases occurred within 3 months, with the majority of these occurring within 4 weeks.