Purpose: A subset of patients with adenocarcinoma of the lung who had never smoked cigarettes showed excellent tumor responses to gefitinib therapy. To evaluate the efficacy of gefitinib as a first-line therapy in this subgroup of patients, we conducted a phase II study.
Experimental design: Eligible patients had no smoking history, stage IIIB or IV adenocarcinoma, Eastern Cooperative Oncology Group performance status 0 to 2, and adequate organ functions. Treatment consisted of daily oral administration ofF 250 mg gefitinib for 28 days until disease progression. Responses were assessed after every two cycles of therapy.
Results: Of 37 patients enrolled, 36 were assessed for response. Twenty-five patients (69%) had partial response, 4 (11%) had stable disease, and 7 (19%) had progressive disease. Of 10 patients with evaluable brain metastases, 7 had objective responses in both intracranial and extracranial lesions, 1 had stable disease in the brain and dramatic response in the extracranial lesions, and 2 had progressive disease in both sites. After a median follow-up of 48 weeks (range, 4-70 weeks), 26 patients had disease progression, with median progression-free survival of 33 weeks, and 9 patients died, all due to disease progression. The median survival time has not been reached yet but the estimated 1-year survival rate was 73%. Common toxicities were skin rash and mild diarrhea but there was no significant hematologic toxicity.
Conclusions: Gefitinib showed very dramatic antitumor activity, even in the brain, with unprecedented survival outcome in never-smoker adenocarcinoma patients. These data support the use of gefitinib as a first-line therapy in this particular subgroup.