Progression-free and overall survival analysis in patients with metastatic melanoma undergoing first- versus second-line therapy

Abstract

9078 Background: A frequently discussed topic at meetings of oncologists is the question of expected clinical outcomes for patients with metastatic melanoma undergoing 1st vs 2nd line systemic therapy. Differing outcomes in these two patient populations could affect interpretation of non-randomized clinical trials involving both patient populations. Some have suggested superior clinical outcome in patients undergoing 2nd line therapy. As there is little data addressing this issue, we sought to answer the question by comparing the clinical outcomes of patients with metastatic melanoma treated on 1st vs 2nd line therapy across clinical trials conducted at our institution. Methods: Data were collected from 10 phase II clinical trials for patients with stage IV melanoma for which Mayo Clinic was the data center. The 10 trials included three categories of treatments: cytotoxic chemotherapy (4), cancer vaccines (4), and biologic agents (2). In all studies, eligibility criteria required: stage IV melanoma, life expectancy >3 months, reasonable hematology and serum chemistry laboratory results, and an ECOG performance status of ≤2. Cox proportional hazards models were fit to assess the relationship between patients' “therapy” status (1st vs 2nd line) and time to events, both overall survival (OS) and progression free survival (PFS), for each treatment category. Results: We identified 318 unique eligible patients across 10 trials. Removed from the analysis were 55 patients (ocular melanoma and/or metastases involving the central nervous system) leaving 263. Cox proportional hazards results demonstrated no differences in PFS or OS for 1st vs 2nd line patients for either “chemotherapy” or “vaccine” treatment regimens. However, patient treated on “biologic” trials as 1st line therapy appeared to demonstrate a PFS advantage over 2nd line treatments (HR=1.98, p-value=0.02). There was a suggestion of an OS benefit for 1st line patients in this category, however, the relationship was not significant (HR=1.77, p=0.07). Conclusions: The presented data suggest that there is no PFS/OS difference in stage IV melanoma patients receiving 1st vs 2nd line therapy (no PFS/OS advantage to patients treated in 2nd line vs. 1st line). No significant financial relationships to disclose.