Treatment of metastatic renal cancer with high-dose interleukin-2 after targeted therapy.

Abstract

439 Background: High-Dose Interleukin-2 (HD IL2) remains a good option for treatment of metastatic renal cancer. As a first-line treatment, in carefully selected patients, it can produce high rates of response ( OR 50%; CR 25%) (Shablak A et al., J Immunotherapy 2011, 34(1):107-122). Its use after targeted therapies is controversial and there are reports of increased toxicity, particularly an increased incidence of cardiovascular toxicity (and possibly a reduced response rate (Cho DC et al., J Immunotherapy 2009, 32(2):181-520). However, there is potential to use it either in patients who have failed treatment with targeted therapy or as a consolidation therapy after successful treatment with a targeted agent. Methods: Here we present the outcomes of 16 patients treated with first-line immunotherapy with HD-IL2 after targeted therapy: of these 8 had been treated after failure of 1-3 lines of targeted therapy and 8 have been treated as consolidation after initial response to sunitinib. The histological characteristics of the tumours all fitted into the “favourable” group as defined previously by us and all had high levels of expression of CAIX (> 80%). All had ECOG PS 0/1, a satisfactory baseline stress echo, an interval of at least 8 weeks from last dose of targeted agent to start of HD-IL2 and at most 2 organs of disease. Results: Toxicity is indistinguishable from that of patients without prior treatment and no patient needed inotropic support or admission to intensive care. The number of doses given per cycle was also similar to that in unpretreated patients. Overall the response rates are excellent – with 9/13 evaluable patients having RECIST defined response and 6/13 having a complete remission. To date none of the patients in complete remission have realpsed but follow up is relatively short with the longest being 24 months. The responses have been particularly striking following treatment with mTor inhibitors. Conclusions: Overall, HD IL2 can be given safely in carefully selected patients after targeted therapies. It appears to be effective as a salvage therapy and potentially as a consolidation therapy. Updated results will be presented.