Development and validation of a nomogram incorporating gene expression profiling and clinical factors for accurate prediction of metastasis in patients with cutaneous melanoma following Mohs micrographic surgery.

BACKGROUND: There is a need to improve prognostic accuracy for patients with cutaneous melanoma. A 31-gene expression profile (31-GEP) test uses the molecular biology of primary tumors to identify individual patient metastatic risk. OBJECTIVE: Develop a nomogram incorporating 31-GEP with relevant clinical factors to improve prognostic accuracy. METHODS: In an IRB-approved study, 1124 patients from 9 Mohs micrographic surgery centers were prospectively enrolled, treated with Mohs micrographic surgery, and underwent 31-GEP testing. Data from 684 of those patients with at least 1-year follow-up or a metastatic event were included in nomogram development to predict metastatic risk. RESULTS: Logistic regression modeling of 31-GEP results and T stage provided the simplest nomogram with the lowest Bayesian information criteria score. Validation in an archival cohort (n = 901) demonstrated a significant linear correlation between observed and nomogram-predicted risk of metastasis. The resulting nomogram more accurately predicts the risk for cutaneous melanoma metastasis than T stage or 31-GEP alone. LIMITATIONS: The patient population is representative of Mohs micrographic surgery centers. Sentinel lymph node biopsy was not performed for most patients and could not be used in the nomogram. CONCLUSIONS: Integration of 31-GEP and T stage can gain clinically useful prognostic information from data obtained noninvasively.

Shortened ex vivo manufacturing time of EGFRvIII-specific chimeric antigen receptor (CAR) T cells reduces immune exhaustion and enhances antiglioma therapeutic function.

BACKGROUND: Non-viral manufacturing of CAR T cells via the Sleeping Beauty transposon is cost effective and reduces the risk of insertional mutagenesis from viral transduction. However, the current gold standard methodology requires ex vivo numerical expansion of these cells on artificial antigen-presenting cells (AaPCs) for 4 weeks to generate CAR T cells of presumed sufficient quantity and function for clinical applications. METHOD: We engineered EGFRvIII-specific CAR T cells and monitored phenotypic changes throughout their ex vivo manufacturing. To reduce the culture time required to generate the CAR T-cell population, we selected for T cells in peripheral blood mononuclear cells prior to CAR modification (to eliminate the competing NK cell population). RESULTS: While we found increased expression of exhaustion markers (such as PD-1, PD-L1, TIM-3, and LAG-3) after 2 weeks in culture, whose levels continued to rise over time, we were able to generate a CAR+ T-cell population with comparable CAR expression and cell numbers in 2 weeks, thereby reducing manufacturing time by 50%, with lower expression of immune exhaustion markers. The CAR T cells manufactured at 2 weeks showed superior therapeutic efficacy in mice bearing established orthotopic EGFRvIII+ U87 gliomas. CONCLUSION: These findings demonstrate a novel, rapid method to generate CAR T cells by non-viral modification that results in CAR T cells superior in phenotype and function and further emphasizes that careful monitoring of CAR T-cell phenotype prior to infusion is critical for generating an optimal CAR T-cell product with full antitumor potential.

Improved cutaneous melanoma survival stratification through integration of 31-gene expression profile testing with the American Joint Committee on Cancer 8th Edition Staging.

Cutaneous melanoma (CM) survival is assessed using averaged data from the American Joint Committee on Cancer 8th edition (AJCC8). However, subsets of AJCC8 stages I-III have better or worse survival than the predicted average value. The objective of this study was to determine if the 31-gene expression profile (31-GEP) test for CM can further risk-stratify melanoma-specific mortality within each AJCC8 stage. This retrospective multicenter study of 901 archival CM samples obtained from patients with stages I-III CM assessed 31-GEP test predictions of 5-year melanoma-specific survival (MSS) using Kaplan-Meier and Cox proportional hazards. In stage I-III CM population, patients with a Class 2B result had a lower 5-year MSS (77.8%) than patients with a Class 1A result (98.7%) and log-rank testing demonstrated significant stratification of MSS [χ2 (2df, n = 901) = 99.7, P < 0.001). Within each stage, 31-GEP data provided additional risk stratification, including in stage I [χ2 (2df, n = 415) = 11.3, P = 0.004]. Cox regression multivariable analysis showed that the 31-GEP test was a significant predictor of melanoma-specific mortality (MSM) in patients with stage I-III CM [hazard ratio: 6.44 (95% confidence interval: 2.61-15.85), P < 0.001]. This retrospective study focuses on Class 1A versus Class 2B results. Intermediate results (Class 1B/2A) comprised 21.6% of cases with survival rates between Class 1A and 2B, and similar to 5-year MSS AJCC stage values. Data from the 31-GEP test significantly differentiates MSM into lower (Class 1A) and higher risk (Class 2B) groups within each AJCC8 stage. Incorporating 31-GEP results into AJCC8 survival calculations has the potential to more precisely assess survival and enhance management guidance.

Long-Term Outcomes in a Multicenter, Prospective Cohort Evaluating the Prognostic 31-Gene Expression Profile for Cutaneous Melanoma.

PURPOSE: Current guidelines for postoperative management of patients with stage I-IIA cutaneous melanoma (CM) do not recommend routine cross-sectional imaging, yet many of these patients develop metastases. Methods that complement American Joint Committee on Cancer (AJCC) staging are needed to improve identification and treatment of these patients. A 31-gene expression profile (31-GEP) test predicts metastatic risk as low (class 1) or high (class 2). Prospective analysis of CM outcomes was performed to test the hypotheses that the 31-GEP provides prognostic value for patients with stage I-III CM, and that patients with stage I-IIA melanoma and class 2 31-GEP results have metastatic risk similar to patients for whom surveillance is recommended. MATERIALS AND METHODS: Two multicenter registry studies, INTEGRATE (ClinicalTrials.gov identifier:NCT02355574) and EXPAND (ClinicalTrials.gov identifier:NCT02355587), were initiated under institutional review board approval, and 323 patients with stage I-III CM and median follow-up time of 3.2 years met inclusion criteria. Primary end points were 3-year recurrence-free survival (RFS), distant metastasis-free survival (DMFS), and overall survival (OS). RESULTS: The 31-GEP was significant for RFS, DMFS, and OS in a univariate analysis and was a significant, independent predictor of RFS, DMFS, and OS in a multivariable analysis. GEP class 2 results were significantly associated with lower 3-year RFS, DMFS, and OS in all patients and those with stage I-IIA disease. Patients with stage I-IIA CM and a class 2 result had recurrence, distant metastasis, and death rates similar to patients with stage IIB-III CM. Combining 31-GEP results and AJCC staging enhanced sensitivity over each approach alone. CONCLUSION: These data provide a rationale for using the 31-GEP along with AJCC staging, and suggest that patients with stage I-IIA CM and a class 2 31-GEP signature may be candidates for more intense follow-up.

Opening of the Blood-Brain Barrier Using Low-Intensity Pulsed Ultrasound Enhances Responses to Immunotherapy in Preclinical Glioma Models.

PURPOSE: The blood-brain barrier (BBB) inhibits adequate dosing/penetration of therapeutic agents to malignancies in the brain. Low-intensity pulsed ultrasound (LIPU) is a safe therapeutic method of temporary BBB disruption (BBBD) to enhance chemotherapeutic delivery to the tumor and surrounding brain parenchyma for treatment of glioblastoma. EXPERIMENTAL DESIGN: We investigated if LIPU could enhance therapeutic efficacy of anti-PD-1 in C57BL/6 mice bearing intracranial GL261 gliomas, epidermal growth factor receptor variant III (EGFRvIII) chimeric antigen receptor (CAR) T cells in NSG mice with EGFRvIII-U87 gliomas, and a genetically engineered antigen-presenting cell (APC)-based therapy producing the T-cell attracting chemokine CXCL10 in the GL261-bearing mice. RESULTS: Mice treated with anti-PD-1 and LIPU-induced BBBD had a median survival duration of 58 days compared with 39 days for mice treated with anti-PD-1, and long-term survivors all remained alive after contralateral hemisphere rechallenge. CAR T-cell administration with LIPU-induced BBBD resulted in significant increases in CAR T-cell delivery to the CNS after 24 (P < 0.005) and 72 (P < 0.001) hours and increased median survival by greater than 129%, in comparison with CAR T cells alone. Local deposition of CXCL10-secreting APCs in the glioma microenvironment with LIPU enhanced T-cell glioma infiltration during the therapeutic window (P = 0.004) and markedly enhanced survival (P < 0.05). CONCLUSIONS: LIPU increases immune therapeutic delivery to the tumor microenvironment with an associated increase in survival and is an emerging technique for enhancing novel therapies in the brain.

Steering CAR T cells to distinguish friend from foe.

CD19-specific chimeric antigen receptor (CAR)+ T cells have demonstrated clinical efficacy and long-lasting remissions, concomitant with tolerable normal B-cell aplasia. However, many tumor-associated antigens (TAAs) are expressed on normal tissues, the destruction of which would lead to intolerable toxicity. Thus, there is a need to engineer CAR+ T cells with improved safety profiles to restrict toxicity against TAA-expressing normal tissues. Bioengineering approaches include: (i) targeting CAR+ T cells to the tumor site, (ii) limiting CAR+ T-cell persistence, and (iii) restricting CAR activation. We review and evaluate strategies to engineer CAR+ T cells to reduce the potential of on-target, off-tissue toxicity.

Osteopontin mediates glioblastoma-associated macrophage infiltration and is a potential therapeutic target.

Glioblastoma is highly enriched with macrophages, and osteopontin (OPN) expression levels correlate with glioma grade and the degree of macrophage infiltration; thus, we studied whether OPN plays a crucial role in immune modulation. Quantitative PCR, immunoblotting, and ELISA were used to determine OPN expression. Knockdown of OPN was achieved using complementary siRNA, shRNA, and CRISPR/Cas9 techniques, followed by a series of in vitro functional migration and immunological assays. OPN gene-deficient mice were used to examine the roles of non-tumor-derived OPN on survival of mice harboring intracranial gliomas. Patients with mesenchymal glioblastoma multiforme (GBM) show high OPN expression, a negative survival prognosticator. OPN is a potent chemokine for macrophages, and its blockade significantly impaired the ability of glioma cells to recruit macrophages. Integrin αvß5 (ITGαvß5) is highly expressed on glioblastoma-infiltrating macrophages and constitutes a major OPN receptor. OPN maintains the M2 macrophage gene signature and phenotype. Both tumor-derived and host-derived OPN were critical for glioma development. OPN deficiency in either innate immune or glioma cells resulted in a marked reduction in M2 macrophages and elevated T cell effector activity infiltrating the glioma. Furthermore, OPN deficiency in the glioma cells sensitized them to direct CD8+ T cell cytotoxicity. Systemic administration in mice of 4-1BB-OPN bispecific aptamers was efficacious, increasing median survival time by 68% (P < 0.05). OPN is thus an important chemokine for recruiting macrophages to glioblastoma, mediates crosstalk between tumor cells and the innate immune system, and has the potential to be exploited as a therapeutic target.

Redirecting T-Cell Specificity to EGFR Using mRNA to Self-limit Expression of Chimeric Antigen Receptor.

Potential for on-target, but off-tissue toxicity limits therapeutic application of genetically modified T cells constitutively expressing chimeric antigen receptors (CARs) from tumor-associated antigens expressed in normal tissue, such as epidermal growth factor receptor (EGFR). Curtailing expression of CAR through modification of T cells by in vitro-transcribed mRNA species is one strategy to mitigate such toxicity. We evaluated expression of an EGFR-specific CAR coded from introduced mRNA in human T cells numerically expanded ex vivo to clinically significant numbers through coculture with activating and propagating cells (AaPC) derived from K562 preloaded with anti-CD3 antibody. The density of AaPC could be adjusted to affect phenotype of T cells such that reduced ratio of AaPC resulted in higher proportion of CD8 and central memory T cells that were more conducive to electrotransfer of mRNA than T cells expanded with high ratios of AaPC. RNA-modified CAR T cells produced less cytokine, but demonstrated similar cytolytic capacity as DNA-modified CAR T cells in response to EGFR-expressing glioblastoma cells. Expression of CAR by mRNA transfer was transient and accelerated by stimulation with cytokine and antigen. Loss of CAR abrogated T-cell function in response to tumor and normal cells expressing EGFR. We describe a clinically applicable method to propagate and modify T cells to transiently express EGFR-specific CAR to target EGFR-expressing tumor cells that may be used to limit on-target, off-tissue toxicity to normal tissue.

Prioritization schema for immunotherapy clinical trials in glioblastoma.

BACKGROUND: Emerging immunotherapeutic strategies for the treatment of glioblastoma (GBM) such as dendritic cell (DC) vaccines, heat shock proteins, peptide vaccines, and adoptive T-cell therapeutics, to name a few, have transitioned from the bench to clinical trials. With upcoming strategies and developing therapeutics, it is challenging to critically evaluate the practical, clinical potential of individual approaches and to advise patients on the most promising clinical trials. METHODS: The authors propose a system to prioritize such therapies in an organized and data-driven fashion. This schema is based on four categories of factors: antigenic target robustness, immune-activation and -effector responses, preclinical vetting, and early evidence of clinical response. Each of these categories is subdivided to focus on the most salient elements for developing a successful immunotherapeutic approach for GBM, and a numerical score is generated. RESULTS: The Score Card reveals therapeutics that have the most robust data to support their use, provides a reference prioritization score, and can be applied in a reiterative fashion with emerging data. CONCLUSIONS: The authors hope that this schema will give physicians an evidence-based and rational framework to make the best referral decisions to better guide and serve this patient population.

Tuning Sensitivity of CAR to EGFR Density Limits Recognition of Normal Tissue While Maintaining Potent Antitumor Activity.

Many tumors overexpress tumor-associated antigens relative to normal tissue, such as EGFR. This limits targeting by human T cells modified to express chimeric antigen receptors (CAR) due to potential for deleterious recognition of normal cells. We sought to generate CAR(+) T cells capable of distinguishing malignant from normal cells based on the disparate density of EGFR expression by generating two CARs from monoclonal antibodies that differ in affinity. T cells with low-affinity nimotuzumab-CAR selectively targeted cells overexpressing EGFR, but exhibited diminished effector function as the density of EGFR decreased. In contrast, the activation of T cells bearing high-affinity cetuximab-CAR was not affected by the density of EGFR. In summary, we describe the generation of CARs able to tune T-cell activity to the level of EGFR expression in which a CAR with reduced affinity enabled T cells to distinguish malignant from nonmalignant cells.

Epidermal growth factor receptor and variant III targeted immunotherapy.

Immunotherapeutic approaches to cancer have shown remarkable promise. A critical barrier to successfully executing such immune-mediated interventions is the selection of safe yet immunogenic targets. As patient deaths have occurred when tumor-associated antigens shared by normal tissue have been targeted by strong cellular immunotherapeutic platforms, route of delivery, target selection and the immune-mediated approach undertaken must work together to maximize efficacy with safety. Selected tumor-specific targets can spare potential toxicity to normal tissue; however, they are far less common than tumor-associated antigens and may not be present on all patients. In the context of immunotherapy for high-grade glioma, 2 of the most prominently studied antigens are the tumor-associated epidermal growth factor receptor and its tumor-specific genetic deletion variant III. In this review, we will summarize the immune-mediated strategies employed against these targets as well as the caveats particular to these approaches.