Infusion Product TNFα, Th2, and STAT3 Activities Are Associated with Clinical Responses to Transgenic T-cell Receptor Cell Therapy.

Transgenic T-cell receptor (TCR) T cell-based adoptive cell therapies for solid tumors are associated with dramatic initial response rates, but there remain many instances of treatment failure and disease relapse. The association of infusion product cytokine profiles with clinical response has not been explored in the context of TCR T-cell therapy products. Single-cell antigen-dependent secretomic and proteomic analysis of preinfusion clinical TCR T-cell therapy products revealed that TNFα cytokine functionality of CD8+ T cells and phospho-STAT3 signaling in these cells were both associated with superior clinical responsiveness to therapy. By contrast, CD4+ T-helper 2 cell cytokine profiles were associated with inferior clinical responses. In parallel, preinfusion levels of IL15, Flt3-L, and CX3CL1 were all found to be associated with clinical response to therapy. These results have implications for the development of therapeutic biomarkers and identify potential targets for enrichment in the design of transgenic TCR T-cell therapies for solid tumors.

Immunotherapy resistance driven by loss of NY-ESO-1 expression in response to transgenic adoptive cellular therapy with PD-1 blockade.

BACKGROUND: The tumor antigen NY-ESO-1 has been shown to be an effective target for transgenic adoptive cell therapy (ACT) for the treatment of sarcoma and melanoma. However, despite frequent early clinical responses, many patients ultimately develop progressive disease. Understanding the mechanisms underlying treatment resistance is crucial to improve future ACT protocols. Here, we describe a novel mechanism of treatment resistance in sarcoma involving loss of expression of NY-ESO-1 in response to transgenic ACT with dendritic cell (DC) vaccination and programmed cell death protein-1 (PD-1) blockade. METHODS: A HLA-A*02:01-positive patient with an NY-ESO-1-positive undifferentiated pleomorphic sarcoma was treated with autologous NY-ESO-1-specific T-cell receptor (TCR) transgenic lymphocytes, NY-ESO-1 peptide-pulsed DC vaccination, and nivolumab-mediated PD-1 blockade. RESULTS: Peripheral blood reconstitution with NY-ESO-1-specific T cells peaked within 2 weeks of ACT, indicating rapid in vivo expansion. There was initial tumor regression, and immunophenotyping of the peripheral transgenic T cells showed a predominantly effector memory phenotype over time. Tracking of transgenic T cells to the tumor sites was demonstrated in on-treatment biopsy via both TCR sequencing-based and RNA sequencing-based immune reconstitution, and nivolumab binding to PD-1 on transgenic T cells was confirmed at the tumor site. At the time of disease progression, the promoter region of NY-ESO-1 was found to be extensively methylated, and tumor NY-ESO-1 expression was completely lost as measured by RNA sequencing and immunohistochemistry. CONCLUSIONS: ACT of NY-ESO-1 transgenic T cells given with DC vaccination and anti-PD-1 therapy resulted in transient antitumor activity. NY-ESO-1 expression was lost in the post-treatment sample in the setting of extensive methylation of the NY-ESO-1 promoter region. BIOLOGICAL/CLINICAL INSIGHT: Antigen loss represents a novel mechanism of immune escape in sarcoma and a new point of improvement in cellular therapy approaches. TRIAL REGISTRATION NUMBER: NCT02775292.

A Phase I, Open-label, Dose-escalation, and Cohort Expansion Study to Evaluate the Safety and Immune Response to Autologous Dendritic Cells Transduced With AdGMCA9 (DC-AdGMCAIX) in Patients With Metastatic Renal Cell Carcinoma.

Expression of carbonic-anhydrase IX (CAIX) in clear cell renal cell carcinoma (RCC) makes it an attractive vaccine target. We developed a fusion-gene construct, granulocyte-macrophage (GM) colony-stimulating factor+CAIX, delivered by an adenoviral vector (Ad) into autologous dendritic cells (DCs) in this phase 1 study. The injected immature DCs were expected to stimulate an antigen-specific immune response against CAIX expressing RCC. Three dose-escalation cohorts (5, 15, and 50×10 cells/administration) were injected intradermally q2wk×3 doses based on a 3+3 design. The primary objective was the safety of the injections. Secondary objectives were immune responses using enzyme-linked immunosorbent spot, a serum biomarker panel, and clinical response. Fifteen patients with metastatic RCC were enrolled, and 9 patients received all 3 doses. No serious adverse events were seen. There were 3 (33%) patients with grade 1 fatigue, 1 of whom subsequently experienced grade 2 fatigue. One patient (11%) experienced grade 1-2 leukopenia. Only 1 patient (11%) experienced grade 2 flu-like symptoms. Of the 9 patients who received treatment, 1 expired of progressive disease, 2 patients were lost to follow-up and 6 patients are alive. Of the 6 patients, 5 have progressive disease, and 1 has completed treatment with stable disease at 27 months follow-up. Immune response measurements appeared more robust in higher dose cohorts, which appeared to be related to patients with stable disease at 3 months. These early data show that autologous immature DC-AdGMCAIX can be safely given to metastatic RCC patients without any serious adverse events with CAIX-specific immune response elicited by the treatment. These preliminary data support further study of Ad-GMCAIX, particularly with combination therapies that may enhance clinical activity.

Epigenetic Suppression of Transgenic T-cell Receptor Expression via Gamma-Retroviral Vector Methylation in Adoptive Cell Transfer Therapy.

Transgenic T-cell receptor (TCR) adoptive cell therapies recognizing tumor antigens are associated with robust initial response rates, but frequent disease relapse. This usually occurs in the setting of poor long-term persistence of cells expressing the transgenic TCR, generated using murine stem cell virus (MSCV) γ-retroviral vectors. Analysis of clinical transgenic adoptive cell therapy products in vivo revealed that despite strong persistence of the transgenic TCR DNA sequence over time, its expression was profoundly decreased over time at the RNA and protein levels. Patients with the greatest degrees of expression suppression displayed significant increases in DNA methylation over time within the MSCV promoter region, as well as progressive increases in DNA methylation within the entire MSCV vector over time. These increases in vector methylation occurred independently of its integration site within the host genomes. These results have significant implications for the design of future viral vector gene-engineered adoptive cell transfer therapies. SIGNIFICANCE: Cellular immunotherapies' reliance on retroviral vectors encoding foreign genetic material can be vulnerable to progressive acquisition of DNA methylation and subsequent epigenetic suppression of the transgenic product in TCR adoptive cell therapy. This must be considered in the design of future generations of cellular immunotherapies for cancer.This article is highlighted in the In This Issue feature, p. 1611.

Development of Hematopoietic Stem Cell-Engineered Invariant Natural Killer T Cell Therapy for Cancer.

Invariant natural killer T (iNKT) cells are potent immune cells for targeting cancer; however, their clinical application has been hindered by their low numbers in cancer patients. Here, we developed a proof-of-concept for hematopoietic stem cell-engineered iNKT (HSC-iNKT) cell therapy with the potential to provide therapeutic levels of iNKT cells for a patient's lifetime. Using a human HSC engrafted mouse model and a human iNKT TCR gene engineering approach, we demonstrated the efficient and long-term generation of HSC-iNKT cells in vivo. These HSC-iNKT cells closely resembled endogenous human iNKT cells, could deploy multiple mechanisms to attack tumor cells, and effectively suppressed tumor growth in vivo in multiple human tumor xenograft mouse models. Preclinical safety studies showed no toxicity or tumorigenicity of the HSC-iNKT cell therapy. Collectively, these results demonstrated the feasibility, safety, and cancer therapy potential of the proposed HSC-iNKT cell therapy and laid a foundation for future clinical development.

IND-Enabling Studies for a Clinical Trial to Genetically Program a Persistent Cancer-Targeted Immune System.

PURPOSE: To improve persistence of adoptively transferred T-cell receptor (TCR)-engineered T cells and durable clinical responses, we designed a clinical trial to transplant genetically-modified hematopoietic stem cells (HSCs) together with adoptive cell transfer of T cells both engineered to express an NY-ESO-1 TCR. Here, we report the preclinical studies performed to enable an investigational new drug (IND) application. EXPERIMENTAL DESIGN: HSCs transduced with a lentiviral vector expressing NY-ESO-1 TCR and the PET reporter/suicide gene HSV1-sr39TK and T cells transduced with a retroviral vector expressing NY-ESO-1 TCR were coadministered to myelodepleted HLA-A2/Kb mice within a formal Good Laboratory Practice (GLP)-compliant study to demonstrate safety, persistence, and HSC differentiation into all blood lineages. Non-GLP experiments included assessment of transgene immunogenicity and in vitro viral insertion safety studies. Furthermore, Good Manufacturing Practice (GMP)-compliant cell production qualification runs were performed to establish the manufacturing protocols for clinical use. RESULTS: TCR genetically modified and ex vivo-cultured HSCs differentiated into all blood subsets in vivo after HSC transplantation, and coadministration of TCR-transduced T cells did not result in increased toxicity. The expression of NY-ESO-1 TCR and sr39TK transgenes did not have a detrimental effect on gene-modified HSC's differentiation to all blood cell lineages. There was no evidence of genotoxicity induced by the lentiviral vector. GMP batches of clinical-grade transgenic cells produced during qualification runs had adequate stability and functionality. CONCLUSIONS: Coadministration of HSCs and T cells expressing an NY-ESO-1 TCR is safe in preclinical models. The results presented in this article led to the FDA approval of IND 17471.

A Pilot Trial of the Combination of Transgenic NY-ESO-1-reactive Adoptive Cellular Therapy with Dendritic Cell Vaccination with or without Ipilimumab.

PURPOSE: Transgenic adoptive cell therapy (ACT) targeting the tumor antigen NY-ESO-1 can be effective for the treatment of sarcoma and melanoma. Preclinical models have shown that this therapy can be improved with the addition of dendritic cell (DC) vaccination and immune checkpoint blockade. We studied the safety, feasibility, and antitumor efficacy of transgenic ACT with DC vaccination, with and without CTLA-4 blockade with ipilimumab. PATIENTS AND METHODS: Freshly prepared autologous NY-ESO-1-specific T-cell receptor (TCR) transgenic lymphocytes were adoptively transferred together with NY-ESO-1 peptide-pulsed DC vaccination in HLA-A2.1-positive subjects alone (ESO, NCT02070406) or with ipilimumab (INY, NCT01697527) in patients with advanced sarcoma or melanoma. RESULTS: Six patients were enrolled in the ESO cohort, and four were enrolled in the INY cohort. Four out of six patients treated per ESO (66%), and two out of four patients treated per INY (50%) displayed evidence of tumor regression. Peripheral blood reconstitution with NY-ESO-1-specific T cells peaked within 2 weeks of ACT, indicating rapid in vivo expansion. Tracking of transgenic T cells to the tumor sites was demonstrated in on-treatment biopsies via TCR sequencing. Multiparametric mass cytometry of transgenic cells demonstrated shifting of transgenic cells from memory phenotypes to more terminally differentiated effector phenotypes over time. CONCLUSIONS: ACT of fresh NY-ESO-1 transgenic T cells prepared via a short ex vivo protocol and given with DC vaccination, with or without ipilimumab, is feasible and results in transient antitumor activity, with no apparent clinical benefit of the addition of ipilimumab. Improvements are needed to maintain tumor responses.