Full adaptome repertoire analysis of immunotherapy to predict responsiveness and correlation with CD8-LAG3, sLAG3, and hepatocyte growth factor levels in patients with renal cancer.

Abstract

e16116 Background: Aldesleukin (recombinant interleukin-2, IL-2), the first checkpoint inhibitor overcoming Tregs, was FDA-approved for mRCC with a 5-10% rate of durable CRs and 25% ORR. Hydroxychloroquine (HCQ) inhibits autophagy, promoting tumor apoptosis. In murine models, IL-2 and HCQ is associated with diminished toxicity and increased efficacy. We hypothesized that a novel deep seven chain analysis of the TCR and BCR repertoire would correlate with sLAG3, CD8 cytosolic LAG3, and HGF levels, associated with outcomes in RCC patients treated with this regimen. Methods: Patients (pts) received high dose IL-2, 600,000 IU/kg, every 8 hours up to 14 doses/cycle. HCQ was administered orally, starting 2 weeks prior to IL-2 and continued up to one year. The HCQ dose was 600 mg (17pts) or 1200 mg (13pts) daily. A newly available seven chain TCR/BCR Adaptome dimer avoidance multiplex-PCR followed by NextGen Sequencing allowed identification of CDR3’s associated with response and increasing clonal diversity. Results: Of 30 pts in the study, 29 were evaluable for response (3CR, 3PR) with serum samples and seven chain analysis of PBMC with 330x106 total reads of the TCR αβ, TCR γδ, IgH, and κλ light chains. HGF (p < .009) was a significant negative predictor of OS at Day 1 after IL-2 and OS at Day -14 (p < .005). Surprisingly this correlated with the TCRδ/γ ratio (p < .01). Similarly serum sLAG3 and CD8LAG3+ both > median predicted improved PFS (p = 0.019) correlating with total TCRδγ expression, p < .01. Diversity of the TCR αβ but not the TCR γδ nor the IgH, and κλ light chains predicted response, p = .005. Conclusions: IL-2 plus HCQ was well tolerated and clinically active with encouraging increase in the PFS of > 17 months at the 600 mg HCQ dose ( > 4x greater than historical controls). Powerful new technology identifying enhanced responsiveness correlating significantly with diversity of the TCR αβ identifies a novel method for predicting responsiveness to immunotherapy. This unbiased examination of the full repertoire ('Adaptome') measured in the same bioassay correlates with other novel biomarkers and should be widely applicable in the further evolution of immunotherapy. NCT01550367 ; approved as IRB 11-074. Clinical trial information: NCT01550367.