Serum cytokine levels as predictive biomarkers of benefit from ipilimumab in small cell lung cancer.

Background. Immunotherapy has shown efficacy in small cell lung cancer (SCLC), but only a subset of patients benefits. Surrogate biomarkers are urgently needed. Our aim was to evaluate serum Th1, Th2, and proinflammatory cytokines in two cohorts of SCLC patients before and during treatment with chemotherapy with or without ipilimumab and to correlate them with survival. Patients and methods. Two cohorts of SCLC patients were studied: patients treated with chemotherapy (n = 47), and patients treated with chemotherapy plus ipilimumab (n = 37). Baseline, on-treatment and after-treatment serum samples were evaluated for the presence of IL-1beta, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IFN-gamma, TNF-alpha, GM-CSF, and Mip-1alpha using a Luminex assay. Differential changes in cytokines between cohorts were analyzed. Associations between cytokine levels and their changes with overall survival were evaluated. Results. Patients treated with ipilimumab showed a global increase of all cytokines after treatment initiation. A high level of IL-8 at baseline was associated with worse prognosis regardless of treatment. Baseline increased IL-2 levels predicted sensitivity to ipilimumab, while high IL-6 and TNF-alpha predicted resistance. An on-treatment increase in IL-4 levels in patients treated with immune-chemotherapy was associated with a better overall survival. Conclusions. The addition of ipilimumab to standard chemotherapy in SCLC modulates the serum levels of cytokines. Baseline levels and their change over time relate to overall survival. Blood-based biomarkers are convenient for patients, and our results support prospective validation of cytokines as predictive biomarkers for ipilimumab in SCLC.

Development of an RNA-based kit for easy generation of TCR-engineered lymphocytes to control T-cell assay performance.

Cell-based assays to monitor antigen-specific T-cell responses are characterized by their high complexity and should be conducted under controlled conditions to lower multiple possible sources of assay variation. However, the lack of standard reagents makes it difficult to directly compare results generated in one lab over time and across institutions. Therefore TCR-engineered reference samples (TERS) that contain a defined number of antigen-specific T cells and continuously deliver stable results are urgently needed. We successfully established a simple and robust TERS technology that constitutes a useful tool to overcome this issue for commonly used T-cell immuno-assays. To enable users to generate large-scale TERS, on-site using the most commonly used electroporation (EP) devices, an RNA-based kit approach, providing stable TCR mRNA and an optimized manufacturing protocol were established. In preparation for the release of this immuno-control kit, we established optimal EP conditions on six devices and initiated an extended RNA stability study. Furthermore, we coordinated on-site production of TERS with 4 participants. Finally, a proficiency panel was organized to test the unsupervised production of TERS at different laboratories using the kit approach. The results obtained show the feasibility and robustness of the kit approach for versatile in-house production of cellular control samples.

Anti-CTLA-4 therapy broadens the melanoma-reactive CD8+ T cell response.

Anti-CTLA-4 treatment improves the survival of patients with advanced-stage melanoma. However, although the anti-CTLA-4 antibody ipilimumab is now an approved treatment for patients with metastatic disease, it remains unknown by which mechanism it boosts tumor-specific T cell activity. In particular, it is unclear whether treatment amplifies previously induced T cell responses or whether it induces new tumor-specific T cell reactivities. Using a combination ultraviolet (UV)-induced peptide exchange and peptide-major histocompatibility complex (pMHC) combinatorial coding, we monitored immune reactivity against a panel of 145 melanoma-associated epitopes in a cohort of patients receiving anti-CTLA-4 treatment. Comparison of pre- and posttreatment T cell reactivities in peripheral blood mononuclear cell samples of 40 melanoma patients demonstrated that anti-CTLA-4 treatment induces a significant increase in the number of detectable melanoma-specific CD8 T cell responses (P = 0.0009). In striking contrast, the magnitude of both virus-specific and melanoma-specific T cell responses that were already detected before start of therapy remained unaltered by treatment (P = 0.74). The observation that anti-CTLA-4 treatment induces a significant number of newly detected T cell responses-but only infrequently boosts preexisting immune responses-provides strong evidence for anti-CTLA-4 therapy-enhanced T cell priming as a component of the clinical mode of action.