Background: The therapeutic potential of chemotherapy in the treatment of recurrent or metastatic non-small cell lung carcinoma (NSCLC) seems modest. Thus, the search for novel agents and combination regimens with a superior therapeutic index has a high priority. The present combination regimen consisting of mitomycin C, vinorelbine, carboplatin and granulocyte-macrophage colony-stimulating factor (GM-CSF) was chosen because of the known activity of these agents in NSCLC and their potential drug synergism without (nonhematologic) cross-toxicity. To prevent/counteract neutropenia that was assumed to represent the dose-limiting toxicity, the hematopoietic growth factor GM-CSF was routinely adminstered. The objective of our trial was to determine the antitumor efficacy and tolerance of this combination regimen in patients with advanced NSCLC.
Patients and methods: Forty consecutive patients with nonresectable, measurable NSCLC (stage IIIB, 7; stage IV, 33) were treated with an intravenous combination chemotherapy regimen consisting of mitomycin C 8 mg/m2 on day 1, vinorelbine 40 mg/m2 on days 1 and 21, and carboplatin 250 mg/m2 on days 1 and 21; GM-CSF 5 microg/kg was administered subcutaneously on days 2-8 and 22-28. Treatment cycles were repeated every 6 weeks. All patients are evaluable in terms of toxicity and response assessment. A total of 123 courses was administered.
Results: Objective tumor response was notes in 16 patients (40%; 95% confidence interval 24.9-56.7%), including 3 (7.5%) complete and 13 partial responses. There was no change in 12 (31.5%) patients, and 12 had progressive disease. Median duration of response was 6 (range 3-15) months, the median time to progression for all patients was 6.2 (range 1-17.5) months, and the projected median survival time was 8.7 (range 1-23.3) months; the 1-year survival rate was 27.5%. Myelosuppression was the most frequently encountered adverse reaction; WHO grade 3 or 4 granulocytopenia and/or thrombocytopenia occurred in 42.5 and 12.5%, respectively. Other toxicities were generally mild to moderate, and always fully reversible.
Conclusion: With a 40% major response rate and disease stabilization in one additional third of our patients, this drug combination seems to have significant activity against advanced metastatic NSCLC. Due to its subjective tolerance and ease of administration, further investigation of this regimen in the palliative-intent care setting seems warranted.