846P - High-Dose Interleukin-2 (Hd Il2) Armed with Pathology-Based Selection Criteria: a Real Option in Treatment of Metastatic Renal Cell Carcinoma (Mrcc) After Targeted Therapy

Abstract

Listen

Translate article

ABSTRACT Aim: HD IL2 as initial therapy in well-selected patients with mRCC can produce durable complete remissions rarely achieved by other therapies, but its efficacy and feasibility after VEGF-targeted therapies is less certain. Response rates (RR) in unselected patients has been reported as low and with excessive toxicity. We undertook a retrospective study of HD IL2 post-targeted therapy in our centre to assess its efficacy and toxicity, plus the impact of our previously reported pathology-based selection criteria. Methods: Patients were stratified by pathology into 'Favorable' and 'Other' groups. ‘Favourable’ was defined as 50% alveolar/solid, or >50% clear cell features. HD IL2 was administered as per standard dosing and schedule. Clinical records were reviewed retrospectively; survivals were analysed by Kaplan-Meir methods. Results: 35 patients were included in this study from July 2007 to December 2013. Median age 58; 77% male. Median follow-up was 1 year 9 months. Only 4 patients had ‘Other’ histology and none responded - while not encouraging, the number is too small to definitely preclude such patients from treatment. ‘Favourable’ group were analysed in more detail. RR are comparable to that reported in first line HD IL2 with 42% ORR and 19% CR. All patients achieving CR remain disease-free to date (duration of up to 50+ months). Clinical correlates for good outcome include low disease burden and tolerance of more doses. Toxicity was generally easily manageable although there was 1 death due to myocarditis and 2 other reversibile cases of myocarditis. Most patients were treated in medical wards but 2 required admission to intensive care for careful monitoring. Conclusions: While toxicity of HD IL2 may be higher than in treatment-naive patients, it seems less problematic than previously reported. Importantly, our pathology selection criterion developed in the first-line setting seems equally effective in mRCC after failure of targeted therapy. Our data shows that HD IL2 is effective and tolerable, and can produce durable remissions (∼19%). It should be considered as a treatment option in mRCC with ‘Favourable’ histology, and preferrably with limited disease, after failure of VEGF-targeted therapy. Disclosure: All authors have declared no conflicts of interest.