Immunotherapy of genitourinary malignancies

Antibody-Drug Conjugates in Uro-Oncology

Currently available treatment options for patients with refractory metastatic prostate, bladder, or kidney cancers are limited with the prognosis remaining poor. Advances in the pathobiology of tumors has led to the discovery of cancer antigens that may be used as the target for cancer treatment. Antibody-drug conjugates (ADCs) are a relatively new concept in cancer treatment that broaden therapeutic landscape. ADCs are examples of a 'drug delivery into the tumor' system composed of an antigen-directed antibody linked to a cytotoxic drug that may release cytotoxic components after binding to the antigen located on the surface of tumor cells. The clinical properties of drugs are influenced by every component of ADCs. Regarding uro-oncology, enfortumab vedotin (EV) and sacituzumab govitecan (SG) are currently registered for patients with locally advanced or metastatic urothelial cancer following previous treatment with an immune checkpoint inhibitor (iCPI; programmed death receptor-1 [PD-1] or programmed death-ligand 1 [PD-L1]) inhibitor) and platinum-containing chemotherapy. The EV-301 trial showed that EV significantly prolonged the overall survival compared with classic chemotherapy. The TROPHY-U-01 trial conducted to evaluate SG demonstrated promising results as regards the objective response rate and duration of response. The safety and efficacy of ADCs in monotherapy and polytherapy (mainly with iCPIs) for different cancer stages and tumor types are assessed in numerous ongoing clinical trials. The aim of this review is to present new molecular biomarkers, specific mechanisms of action, and ongoing clinical trials of ADCs in genitourinary cancers. In the expert discussion, we assess the place of ADCs in uro-oncology and discuss their clinical value.

A Cancer Research UK First Time in Human Phase I Trial of IMA950 (Novel Multipeptide Therapeutic Vaccine) in Patients with Newly Diagnosed Glioblastoma

PURPOSE

To perform a two-cohort, phase I safety and immunogenicity study of IMA950 in addition to standard chemoradiotherapy and adjuvant temozolomide in patients with newly diagnosed glioblastoma. IMA950 is a novel glioblastoma-specific therapeutic vaccine containing 11 tumor-associated peptides (TUMAP), identified on human leukocyte antigen (HLA) surface receptors in primary human glioblastoma tissue.

EXPERIMENTAL DESIGN

Patients were HLA-A*02-positive and had undergone tumor resection. Vaccination comprised 11 intradermal injections with IMA950 plus granulocyte macrophage colony-stimulating factor (GM-CSF) over a 24-week period, beginning 7 to 14 days prior to initiation of chemoradiotherapy (Cohort 1) or 7 days after chemoradiotherapy (Cohort 2). Safety was assessed according to NCI CTCAE Version 4.0 and TUMAP-specific T-cell immune responses determined. Secondary observations included progression-free survival (PFS), pretreatment regulatory T cell (Treg) levels, and the effect of steroids on T-cell responses.

RESULTS

Forty-five patients were recruited. Related adverse events included minor injection site reactions, rash, pruritus, fatigue, neutropenia and single cases of allergic reaction, anemia and anaphylaxis. Two patients experienced grade 3 dose-limiting toxicity of fatigue and anaphylaxis. Of 40 evaluable patients, 36 were TUMAP responders and 20 were multi-TUMAP responders, with no important differences between cohorts. No effect of pretreatment Treg levels on IMA950 immunogenicity was observed, and steroids did not affect TUMAP responses. PFS rates were 74% at 6 months and 31% at 9 months.

CONCLUSIONS

IMA950 plus GM-CSF was well-tolerated with the primary immunogenicity endpoint of observing multi-TUMAP responses in at least 30% of patients exceeded. Further development of IMA950 is encouraged. Clin Cancer Res; 22(19); 4776-85. ©2016 AACRSee related commentary by Lowenstein and Castro, p. 4760.

Checkpoint inhibitors in bladder and renal cancers: results and perspectives

The field of immunotherapy in urinary malignancy is expanding in several directions and checkpoint inhibitors are leading the way. The aim of this report is to highlight the efficacy and safety profile of the two classes of molecules, anti-cytotoxic T-lymphocyte antigen-4 and anti-programmed death receptor-1/programmed death ligand type 1, that are under investigation and represent potential candidates to be used in the near future for the management of bladder and renal cell cancer. The preliminary results as well as the future perspectives of this novel immunotherapy are analyzed. Novel immune checkpoint targets are reviewed as well.

Rates of MAGE-A3 and PRAME expressing tumors in FFPE tissue specimens from bladder cancer patients: potential targets for antigen-specific cancer immunotherapeutics

INTRODUCTION

Antigen-specific active immunotherapy is an investigational therapeutic approach of potential interest for bladder cancer regardless of disease stage. Clinical development of antigen-specific immunotherapeutics against bladder cancer must be preceded by assessment of the expression of relevant genes in bladder tumors. The objectives of this study (NCT01706185) were to assess the rate of expression of the MAGE-A3 and PRAME genes in bladder tumors and to investigate the feasibility of using formalin-fixed paraffin-embedded (FFPE) tumor tissues for testing.

MATERIALS AND METHODS

Archived FFPE bladder tumor specimens (any stage) were tested for mRNA expression of MAGE-A3 and PRAME using antigen-specific quantitative reverse transcription polymerase chain reaction assays. Data on patients and tumor characteristics were obtained from hospital records to investigate these characteristics' possible association with the antigen expression.

RESULTS

Over 92% of the 156 tumors examined gave valid antigen test results. Of the tumors with a valid test, 46.5% were MAGE-A3-positive, 32.2% were PRAME-positive and 59.7% positive for at least one of them. Exploratory analyses of possible associations between antigen expression and patient or tumor characteristics did not identify clear associations between antigen expression and any of the variables investigated.

CONCLUSIONS

Assessment of tumor antigen mRNA expression by using FFPE bladder tissues was feasible. The rates of MAGE-A3-positive and PRAME-positive tumors indicate that both antigens may be interesting targets for immunotherapeutics against bladder cancer.