Durable Clinical Responses and Long-Term Follow-Up of Stage III–IV Non-Small-Cell Lung Cancer (NSCLC) Patients Treated With IDO Peptide Vaccine in a Phase I Study—A Brief Research Report

Background: Long-term follow-up on a clinical trial of 15 stage III-IV NSCLC patients treated with an Indoleamine 2,3-Dioxygenase (IDO) peptide vaccine (NCT01219348).Methods: Fifteen HLA-A2-positive patients with stable stage III-IV NSCLC after standard chemotherapy were treated with subcutaneous vaccinations (100 μg IDO5 peptide, sequence ALLEIASCL, formulated in 900 μl Montanide) biweekly for 2.5 months and thereafter monthly until progression or up to 5 years. Here we report long-term clinical follow-up, toxicity and immunity.Results: Three of 15 patients are still alive corresponding to a 6-year overall survival of 20 %. Two patients continued monthly vaccinations for 5 years (56 vaccines). One of the two patients developed a partial response (PR) of target lesions in the liver 15 months after the first vaccine and has remained in PR ever since. The other patient had a solitary distant metastasis in a lymph node in retroperitoneum at baseline which normalized during treatment. All following evaluation scans during the treatment have been tumor free. The vaccine was well tolerated for all 5 years with no long-term toxicities registered. The third long-term surviving patient discontinued vaccinations after 11 months due to disease progression. Flow cytometry analyses of PBMCs from the two long-term responders demonstrated stable CD8+ and CD4+ T-cell populations during treatment. In addition, presence of IDO-specific T-cells was detected by IFN-γ Elispot in both patients at several time points during treatment.Conclusion: IDO peptide vaccination was well tolerated for administration up to 5years. Two of 15 patients are long-term responders with ongoing clinical response 6 years after 1st vaccination

Natural CD4+ T-Cell Responses against Indoleamine 2,3-Dioxygenase

The enzyme indoleamine 2,3-dioxygenase (IDO) contributes to immune tolerance in a variety of settings. In cancer IDO is expressed within the tumor itself as well as in antigen-presenting cells in tumor-draining lymph nodes, where it endorses the establishment of peripheral immune tolerance to tumor antigens. Recently, we described cytotoxic CD8(+) T-cell reactivity towards IDO-derived peptides.In the present study, we show that CD4(+) helper T cells additionally spontaneously recognize IDO. Hence, we scrutinized the vicinity of the previously described HLA-A*0201-restricted IDO-epitope for CD4(+) T-cell epitopes. We demonstrated the presence of naturally occurring IDO-specific CD4(+) T cells in cancer patients and to a lesser extent in healthy donors by cytokine release ELISPOT. IDO-reactive CD4(+) T cells released IFN-γ, TNF-α, as well as IL-17. We confirm HLA class II-restriction by the addition of HLA class II specific blocking antibodies. In addition, we detected a trend between class I- and class II-restricted IDO responses and detected an association between IDO-specific CD4(+) T cells and CD8(+) CMV-responses. Finally, we could detect IL-10 releasing IDO-reactive CD4(+) T cells.IDO is spontaneously recognized by HLA class II-restricted, CD4(+) T cells in cancer patients and in healthy individuals. IDO-specific T cells may participate in immune-regulatory networks where the activation of pro-inflammatory IDO-specific CD4(+) responses may well overcome or delay the immune suppressive actions of the IDO-protein, which are otherwise a consequence of the early expression of IDO in maturing antigen presenting cells. In contrast, IDO-specific regulatory T cells may enhance IDO-mediated immune suppression

Immunological correlates of treatment and response in stage IV malignant melanoma patients treated with Ipilimumab

Introduction: Ipilimumab is effective in the treatment of metastatic malignant melanoma, but few biomarkers reliably predict treatment response. Methods: Patients were treated with Ipilimumab for metastatic malignant melanoma. Blood and serum samples were collected before and during treatment. Mononuclear cells in peripheral blood were subjected to immune phenotypic analyses and cytokine levels were measured in serum samples. Results were correlated with clinical data. Results: A total of 40 patients were included in the analyses. Clinical response were associated with an increase after one series of treatment in absolute lymphocyte count (ALC) (p = 0.008), absolute T cell count (p = 0.02) and the absolute number of activated T cells in peripheral blood (p = 0.003). A high frequency of myeloid derived suppressor cells (MDSC) and a higher level of IL6 were associated with treatment failure, though not significantly. Levels of IL6 in serum above the median showed a tendency to associate with reduced survival by the 4th treatment series. Finally, treatment with Ipilimumab led to a decreased frequency of FOXP3+ regulatory T cells (p = 0.009). Conclusion: Ipilimumab leads to increased ALC, T cell count and T cell activation in malignant melanoma patients responding to treatment. A high baseline frequency of myeloid-derived suppressor cells and high levels of IL6 is associated with a reduced chance of responding to therapy

Methods to Improve Adoptive T-Cell Therapy for Melanoma:IFN-γ Enhances Anticancer Responses of Cell Products for Infusion

Further development of adoptive T-cell therapy (ACT) with autologous tumor-infiltrating lymphocytes (TILs) has the potential to markedly change the long-term prognosis of patients with metastatic melanoma, and modifications of the original protocol that can improve its clinical efficacy are highly desirable. In this study, we demonstrated that a high in vitro tumor reactivity of infusion products was associated with clinical responses upon adoptive transfer. In addition, we systematically characterized the responses of a series of TIL products to relevant autologous short term–cultured melanoma cell lines from 12 patients. We provide evidence that antitumor reactivity of both CD8+ and CD4+ T cells could be enhanced in most TIL products by autologous melanoma sensitization by pretreatment with low-dose IFN-γ. IFN-γ selectively enhanced responses to tumor-associated antigens other than melanoma differentiation antigens. In addition, IFN-γ treatment was invariably associated with restored/increased cancer immunogenicity as demonstrated by upregulation of major histocompatibility complex molecules. These findings suggest a potential synergism between IFN-γ and ACT, and have important implications for clinical development of combination strategies for the treatment of metastatic melanoma