Cancer immunotherapy highlights from the 2014 ASCO Meeting

Melanoma Evolves Complete Immunotherapy Resistance through the Acquisition of a Hypermetabolic Phenotype

Despite the clinical success of T-cell checkpoint blockade, most patients with cancer still fail to have durable responses to immunotherapy. The molecular mechanisms driving checkpoint blockade resistance, whether preexisting or evolved, remain unclear. To address this critical knowledge gap, we treated B16 melanoma with the combination of CTLA-4, PD-1, and PD-L1 blockade and a Flt3 ligand vaccine (≥75% curative), isolated tumors resistant to therapy, and serially passaged them in vivo with the same treatment regimen until they developed complete resistance. Using gene expression analysis and immunogenomics, we determined the adaptations associated with this resistance phenotype. Checkpoint resistance coincided with acquisition of a "hypermetabolic" phenotype characterized by coordinated upregulation of the glycolytic, oxidoreductase, and mitochondrial oxidative phosphorylation pathways. These resistant tumors flourished under hypoxic conditions, whereas metabolically starved T cells lost glycolytic potential, effector function, and the ability to expand in response to immunotherapy. Furthermore, we found that checkpoint-resistant versus -sensitive tumors could be separated by noninvasive MRI imaging based solely on their metabolic state. In a cohort of patients with melanoma resistant to both CTLA-4 and PD-1 blockade, we observed upregulation of pathways indicative of a similar hypermetabolic state. Together, these data indicated that melanoma can evade T-cell checkpoint blockade immunotherapy by adapting a hypermetabolic phenotype.

Development, Optimization, and Comparison of Different Sample Pre-Treatments for Simultaneous Determination of Vitamin E and Vitamin K in Vegetables

The absence of vitamin E from the diet can lead to cardiovascular disease, cancer, cataracts, and premature aging. Vitamin K deficiency can lead to bleeding disorders. These fat-soluble vitamins are important nutritional factors that can be determined in different methods in vegetables. In this work, the simultaneous determination of α-tocopherol, α-tocopheryl acetate, phylloquinone, and menaquinone-4 by gas chromatography–mass spectrometry (GC–MS) has been optimized using both direct injection and solid phase microextraction (SPME). Three different sample pre-treatment approaches based on: (A) solid–liquid–liquid–liquid extraction (SLE–LLE), (B) SLE, and (C) SPME were then applied to extract the target analytes from vegetables samples using menaquinone as internal standard. All the procedures allowed the determination of the target analytes in onion, carrot, celery, and curly kale samples. Similar results were obtained with the three different approaches, even if the one based on SPME offers the best performance, together with a reduced use of solvent, time consumption, and experimental complexity, which makes it the preferable option for industrial applications.

Immune Checkpoint Inhibition in Hepatocellular Carcinoma: Basics and Ongoing Clinical Trials

Clinical trials of antibodies targeting the immune checkpoint inhibitors programmed cell death 1 (PD-1), programmed cell death ligand 1 (PD-L1), or cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) for the treatment of advanced hepatocellular carcinoma (HCC) are ongoing. Expansion cohorts of a phase I/II trial of the anti-PD-1 antibody nivolumab in advanced HCC showed favorable results. Two phase III studies are currently ongoing: a comparison of nivolumab and sorafenib in the first-line setting for advanced HCC, and a comparison of the anti-PD-1 antibody pembrolizumab and a placebo in the second-line setting for patients with advanced HCC who progressed on sorafenib therapy. The combination of anti-PD-1/PD-L1 and anti-CTLA-4 antibodies is being evaluated in other phase I/II trials, and the results suggest that an anti-PD-1 antibody combined with locoregional therapy or other molecular targeted agents is an effective treatment strategy for HCC. Immune checkpoint inhibitors may therefore open new doors to the treatment of HCC.

Immunotherapeutic strategies for sexually transmitted viral infections: HIV, HSV and HPV

More than 1 million sexually transmitted infections (STIs) are acquired each day globally. Etiotropic drugs cannot effectively control infectious diseases therefore, there is a dire need to explore alternative strategies especially those based on the regulation of immune system. The review discusses all rational approaches to develop better understanding towards immunotherapeutic strategies based on modulation of immune system in an attempt to curb the elevating risk of infectious diseases such as HIV, HPV and HSV because of their high prevalence. Development of monoclonal antibodies, vaccines and several other immune based treatments are promising alternative strategies that are offering new opportunities to eradicate pathogens.

Recent Trends in the Management of Hepatocellular Carcinoma with Special Emphasis on Treatment with Regorafenib and Immune Checkpoint Inhibitors

Hepatocellular carcinoma (HCC) is the fifth most common cancer and the third leading cause of cancer deaths worldwide. Sonazoid-enhanced ultrasound and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced MRI are the most important imaging modalities in diagnosing HCC. There are 2 non-contradictory HCC treatment algorithms in Japan. Hepatic arterial infusion chemotherapy plays an important role in the treatment of advanced HCC with main or branch portal vein invasion. Regorafenib, as a second-line systemic treatment, prolongs survival in patients with intermediate and advanced HCC who progressed on sorafenib. In recent clinical trials, immune check point inhibitors show promising results for the treatment of HCC. This review describes recent trends in the management of HCC.

Immunotherapies for bladder cancer: a new hope

PURPOSE OF REVIEW

We review recent data on immunotherapies for bladder cancer and discuss strategies to maximize the antitumor effect of immunotherapy in solid tumors.

RECENT FINDINGS

Anti-programmed death ligand 1 has shown promise in advanced bladder cancer. Clinical trials of immune checkpoint inhibitors as monotherapy or in combination are underway. Here we review strategies for enhancing antitumor immunity using immunomodulating agents or combination treatments that may increase tumor response.

SUMMARY

Combining immune checkpoint inhibitors with other treatment modalities may lead to the development of new treatment strategies in advanced bladder cancer; however, identifying predictive biomarkers is essential for appropriate patient selection.

Higher preoperative serum levels of PD-L1 and B7-H4 are associated with invasive and metastatic potential and predictable for poor response to VEGF-targeted therapy and unfavorable prognosis of renal cell carcinoma

Renal cell carcinoma (RCC) is an immunogenic and proangiogenic cancer. Although antivascular endothelial growth factor (VEGF) therapies achieve impressive responses in some patients, many tumors eventually develop resistance to such therapy. The B7 family molecules such as CTLA‐4, PD‐1, and PD‐L1 are pivotal players in immune checkpoints that positively or negatively regulate various immune responses. Recently, immunotherapy based on blocking immune checkpoints with anti‐CTLA4, anti‐PD‐1, or anti‐PD‐L1 antibodies has been proposed as a potential new approach to the treatment of metastatic RCC. Higher expression of PD‐L1 and B7‐H4 in the tumors is associated with a poor prognosis in RCCs, however, the clinical impact of serum levels of B7 family molecules has not been elucidated in patients with metastatic RCCs receiving VEGF‐targeted agents. We assessed the preoperative serum levels of B7 family molecules, including CD80, CD86, PD‐1, PD‐L1, B7‐H3, B7‐H4, and CTLA‐4, and CD28 in RCC patients, and determined their relations with various clinicopathological characteristics. Elevated preoperative serum levels of PD‐L1 and B7‐H4 were correlated with less differentiated tumors, higher invasive and metastatic potential, a worse response to anti‐VEGF therapy, and shorter overall survival. These findings suggested that investigating preoperative serum levels of PD‐L1 and B7‐H4 might not only be useful to assess the biological aggressiveness of RCCs, but also to predict the efficacy of anti‐VEGF therapy and the eventual prognosis, indicating the future design of clinical trials of therapies targeting immune checkpoint in advanced RCCs.

Preoperative palsy score has no significant association with survival in non-small-cell lung cancer patients with spinal metastases who undergo spinal surgery

BACKGROUND

Survival is a key factor physicians consider when selecting a treatment modality for the treatment of spinal metastases. Various assessment systems can predict length of survival and facilitate selection of the most appropriate treatment. Spinal palsy is a prognostic parameter in the Tokuhashi scoring system but not in the Tomita scoring system. A limitation of these scoring systems is that studies of them have included different tumor types. The aim of this study was to evaluate the usefulness of preoperative neurological status as a prognostic factor in non-small-cell lung cancer patients with spinal metastases who underwent surgical treatment.

METHODS

From November 2000 to March 2010, 50 patients with symptomatic metastatic spinal cord compression secondary to non-small-cell lung cancer underwent palliative surgery. Data collected included patient age and sex, tumor histology, date of surgery, death or last follow-up, preoperative and postoperative ambulatory status according to the Frankel grading system, body mass index (BMI), number of vertebra involved, number of other bone metastasis, visceral metastasis, and preoperative Karnofsky performance status. Log-rank test and multivariate Cox proportional hazard regressions were used to evaluate possible prognostic factors.

RESULTS

The mean patient age was 61.6 years (range, 20-87 years), and 34 were male and 16 were female. The median postoperative survival time was 7.5 months. The median survival was 2.5 months (95% confidence interval (CI): 1.22-16.3 months) in the Frankel A + B group and 8.0 months (95% CI: 5.52-9.89 months) in the Frankel C + D group (p = 0.87). Multivariate Cox proportional hazard regressions showed that preoperative performance status was significantly associated with survival. Preoperative palsy score had no statistically significant association with survival.

CONCLUSIONS

Preoperative palsy score had no statistically significant association with survival in non-small-cell lung cancer patients with spinal metastases who underwent spinal surgery in this study.

NK cells and CD8+ T cells cooperate to improve therapeutic responses in melanoma treated with interleukin-2 (IL-2) and CTLA-4 blockade

BACKGROUND

Melanoma is one of the few types of cancer with an increasing annual incidence. While a number of immunotherapies for melanoma have been associated with significant clinical benefit, including high-dose IL-2 and cytotoxic T lymphocyte antigen 4 (CTLA-4) blockade, clinical response to either of these single agents has been limited to 11-20% of treated patients. Therefore, in this study, we sought to test the hypothesis that the combination of IL-2 and CTLA-4 blockade could mediate a more profound therapeutic response.

METHODS

Here, B6 mice were challenged with poorly immunogenic B16 melanoma on day 0, and treated with CTLA-4 blocking antibody (100 μg/mouse) on days 3, 6, and 9, and IL-2 (100,000 units) twice daily on days 4-8, or both.

RESULTS

A highly significant synergistic effect that delayed tumor growth and prolonged survival was demonstrated with the combination immunotherapy compared to either monotherapy alone. The therapeutic effect of combination immunotherapy was dependent on both CD8+ T and NK cells and co-depletion of these subsets (but not either one alone) abrogated the therapeutic effect. CTLA-4 blockade increased immune cell infiltration (including CD8+ T cells and NK cells) in the tumor and IL-2 reduced the proportion of highly differentiated/exhausted tumor-infiltrating NK cells.

CONCLUSIONS

These results have implications for the design of clinical trials in patients with metastatic melanoma and provide new insights into how the immune system may be mediating anti-tumor activity with combination IL-2 and CTLA-4 blockade in melanoma.

Emerging immunotherapies for bladder cancer

PURPOSE OF REVIEW

Inhibition of immune escape mechanisms, such as the programed death-ligand 1 pathway, has demonstrated rapid, durable responses in multiple tumor types, including advanced urothelial carcinoma. This review discusses emerging immunotherapies for urothelial carcinoma in various stages of clinical development.

RECENT FINDINGS

Urothelial carcinoma has a high mutational burden, which may increase the number of tumor antigens and potentially enhance the ability of the immune system to recognize tumor cells as foreign. However, urothelial carcinoma can evade the immune system by downregulating tumor-antigen presentation, upregulating various immune checkpoints, and inactivating cytotoxic T cells. Immunotherapies for urothelial carcinoma target each of these steps to restore immune-mediated cytotoxicity. Many of these agents are in clinical trials for urothelial carcinoma.

SUMMARY

Immunotherapies are active in urothelial carcinoma, but only in a fraction of patients, implying the presence of persistent immune escape. Identifying the mechanisms of immune escape and developing rational combinatorial regimens may make the benefit of immunotherapy accessible to a broader population.

Neoadjuvant chemotherapy in the management of muscle-invasive bladder cancer: bridging the gap between evidence and practice

Although cisplatin-based chemotherapy followed by radical cystectomy is the standard treatment of muscle-invasive bladder cancer, population-based studies reveal that only a small fraction of patients actually receive such treatment. A comprehensive understanding of the reasons for this gap between efficacy and effectiveness is necessary to increase the likelihood of cure of all patients with muscle-invasive bladder cancer. These reasons include systems-, provider-, and patient-level barriers that are not amenable to a single solution. Tackling each barrier will ultimately be necessary to bridge the disconnect between what is achievable and what is actually achieved.

Antibody Blockade of Semaphorin 4D Promotes Immune Infiltration into Tumor and Enhances Response to Other Immunomodulatory Therapies

Semaphorin 4D (SEMA4D, CD100) and its receptor plexin-B1 (PLXNB1) are broadly expressed in murine and human tumors, and their expression has been shown to correlate with invasive disease in several human tumors. SEMA4D normally functions to regulate the motility and differentiation of multiple cell types, including those of the immune, vascular, and nervous systems. In the setting of cancer, SEMA4D-PLXNB1 interactions have been reported to affect vascular stabilization and transactivation of ERBB2, but effects on immune-cell trafficking in the tumor microenvironment (TME) have not been investigated. We describe a novel immunomodulatory function of SEMA4D, whereby strong expression of SEMA4D at the invasive margins of actively growing tumors influences the infiltration and distribution of leukocytes in the TME. Antibody neutralization of SEMA4D disrupts this gradient of expression, enhances recruitment of activated monocytes and lymphocytes into the tumor, and shifts the balance of cells and cytokines toward a proinflammatory and antitumor milieu within the TME. This orchestrated change in the tumor architecture was associated with durable tumor rejection in murine Colon26 and ERBB2(+) mammary carcinoma models. The immunomodulatory activity of anti-SEMA4D antibody can be enhanced by combination with other immunotherapies, including immune checkpoint inhibition and chemotherapy. Strikingly, the combination of anti-SEMA4D antibody with antibody to CTLA-4 acts synergistically to promote complete tumor rejection and survival. Inhibition of SEMA4D represents a novel mechanism and therapeutic strategy to promote functional immune infiltration into the TME and inhibit tumor progression.

Cancer immunotherapy and breaking immune tolerance: new approaches to an old challenge

Cancer immunotherapy has proven to be challenging as it depends on overcoming multiple mechanisms that mediate immune tolerance to self-antigens. A growing understanding of immune tolerance has been the foundation for new approaches to cancer immunotherapy. Adoptive transfer of immune effectors such as antitumor mAb and chimeric antigen receptor T cells bypasses many of the mechanisms involved in immune tolerance by allowing for expansion of tumor-specific effectors ex vivo. Vaccination with whole tumor cells, protein, peptide, or dendritic cells has proven challenging, yet may be more useful when combined with other cancer immunotherapeutic strategies. Immunomodulatory approaches to cancer immunotherapy include treatment with agents that enhance and maintain T-cell activation. Recent advances in the use of checkpoint blockade to block negative signals and to maintain the antitumor response are particularly exciting. With our growing knowledge of immune tolerance and ways to overcome it, combination treatments are being developed, tested, and have particular promise. One example is in situ immunization that is designed to break tolerance within the tumor microenvironment. Progress in all these areas is continuing based on clear evidence that cancer immunotherapy designed to overcome immune tolerance can be useful for a growing number of patients with cancer.