Background: Gefitinib has demonstrated activity in patients with non-small cell lung cancer (NSCLC). Clinical trials have not demonstrated a relationship between response to gefitinib and over-expression of the epidermal growth factor receptor (EGFR). Although, EGFR is not over-expressed in small cell lung cancer (SCLC), we postulated that gefitinib might affect tumor growth through other mechanisms. Agents that are active in NSCLC usually are also effective in SCLC.
Methods: The primary objective was to assess the clinical control rate: complete response (CR) partial response (PR) and stable disease (SD > 90 days), of gefitinib in patients with chemo-resistant and chemo-sensitive small cell cancers. Eligibility criteria included pathologic proof of a neuroendocrine tumor, especially small cell cancer, Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0-2, prior treatment with one or two prior chemotherapy regimens and adequate end-organ function. Patients received gefitinib, 250 mg p.o. daily until disease progression or intolerable side effects.
Results: From April 2003 to March 2004, 19 patients were enrolled. Small cell lung cancer accounted for 18 of the 19 patients and one patient had metastatic Merkel cell carcinoma. Twelve patients (63%) had chemo-sensitive disease, defined as progression greater than three months from completion of prior chemotherapy; 7 (37%) had chemo-refractory disease; 13 (68%) had one prior chemotherapy regimen. Other patient characteristics: mean age 64 years (range 52-79 years); ECOG PS 0/1/2 = 7/9/3, M:F = 9:10. Grade 3 toxicities included: fatigue in three patients (15.8%), pulmonary toxicities in three (15.8%) and one patient (5.3%) each with hyperglycemia or pain. Four patients had grade four toxicities: one patient (5.3%) with fatigue and three patients (15.8%) with dyspnea. There were no patients with grade 3 or 4 rash or diarrhea. Two patients had stable disease (<90 days) and 17 had progressive disease as their best response. This study was a two-stage design and because the continuing criterion for stage one was not met, stage 2 was not performed. Median time to progression (TTP) was 50 days (95% CI = 21-58 days). One year overall survival (OS) was 21% (95% CI = 6-45.6%).
Conclusion: Although gefitinib has activity in select patients with NSCLC, this study failed to demonstrate benefit in patients with small cell lung cancer.