"Real World" Treatment of Metastatic Renal Cell Carcinoma in a Joint Community-academic Cohort: Progression-free Survival over Three Lines of Therapy

Background: New targeted therapeutics approved for metastatic renal cell carcinoma (mRCC) offer multiple options in each line of therapy; however, there are few prospective data beyond the first-line settings, and overall comparative effectiveness data are limited. In the targeted therapy era, progression-free survival (PFS) has been the most common regulatory end point for demonstrating the benefit of new therapies.

Patients And Methods: Drawing on a joint community-academic retrospective mRCC registry, we analyzed all patients who had undergone at least 1 line of systemic therapy (N = 325) for PFS. Patients were grouped according to treatment choice (sorafenib, sunitinib, temsirolimus, everolimus, and "other") for up to 3 lines of therapy. PFS by treatment choice and line of therapy was evaluated using Kaplan-Meier and Cox regression analyses.

Results: PFS was longest in patients treated with sunitinib in the first and second lines of therapy. First-line PFS for sorafenib, sunitinib, temsirolimus, everolimus, and "other" was 6.9, 8.9, 4.2, not analyzed (too few patients), and 10.8 months, respectively. Second-line PFS was 4.6, 7.0, 3.2, 3.8, and 4.1 months, respectively. Third-line PFS was 4.5, 4.6, 9.9, 4.2, and 2.9, months, respectively. The risk of progression in patients treated with temsirolimus was about twice that of patients treated with sunitinib in the first and second lines of therapy.

Conclusion: Patients treated with sunitinib had the longest PFS in the first and second lines of therapy. PFS from practice-based data appear consistent with trial-based expectations; however, practice variation was still evident.