Targeting cytotoxic T-lymphocyte antigen 4 in immunotherapies for melanoma and other cancers

Efficacy and Safety of First-Line Immunotherapy in Combination with Chemotherapy for Patients with Extensive-Stage Small Cell Lung Cancer: A Systematic Review and Network Meta-Analysis

Background

The prognosis of patients with extensive-stage small cell lung cancer (SCLC) is poor. Adding an immune checkpoint inhibitor (ICI) to chemotherapy may exert a synergistic effect and improve survival outcomes. However, for treatment-naive extensive-stage SCLC patients, the efficacy of immunotherapy in combination with cytotoxic chemotherapy remains controversial.

Objective

To evaluate the benefits and risks of the combination of immunotherapy and chemotherapy and to assess the comparative effectiveness of different first-line treatment strategies for extensive-stage SCLC.

Methods

PubMed, Web of Science, EMBASE, and Cochrane Library were searched for randomized clinical trials studying different immunotherapeutics for patients with previously untreated extensive-stage SCLC up to Feb 16, 2020. The primary outcomes were overall survival (OS) and progression-free survival (PFS), and the secondary outcomes were objective response rate (ORR), disease control rate (DCR), and adverse events.

Results

We identified 141 published records, and 4 studies (comprising 2202 patients) were included in the analysis. Immunotherapy (including ipilimumab, atezolizumab, and durvalumab) plus chemotherapy was associated with better OS (hazard ratio (HR) 0.84, 95% confidence interval (CI) 0.75-0.93; risk ratio (RR) 0.90, 95% CI 0.81-1.00) and PFS (HR: 0.81, 95% CI 0.74-0.88; RR 0.96, 95% CI 0.93-0.99) than placebo plus chemotherapy. The addition of immunotherapy to chemotherapy showed similar improvement in ORR, DCR, and adverse events versus placebo plus chemotherapy. On the surface under the cumulative ranking (SUCRA) analysis, the anti-PD-L1 agent, atezolizumab, had the highest likelihood of achieving improved OS (93.4%) and PFS (95.0%).

Conclusion

In the first-line setting, combining immunotherapy with chemotherapy is better than standard chemotherapy in terms of OS and PFS. Across the eligible studies, PD-L1 inhibitors might be preferred. Further explorations of more ICIs in the first-line treatment for extensive-stage SCLC patients should be needed.

Emerging therapies for small cell lung cancer

Currently, chemotherapy remains the standard treatment for first- and second-line management of small cell lung cancer (SCLC). Immunotherapy has made progress in the treatment of SCLC, and nivolumab, pembrolizumab, atezolizumab, and durvalumab have led to significant improvements in clinical outcomes of SCLC. Regarding options in other classes of therapy, the cytotoxic drug lurbinectedin was granted orphan drug status based on a remarkable objective response rate of 39.3%. In addition, an increase in progression-free survival (PFS) was achieved in a phase II study of anlotinib (ALTER 1202). Future prospects for even better outcomes in SCLC lie in novel ways to integrate immunotherapy and small-molecule TKI drugs. Innovative clinical trial designs are needed to efficiently explore the increasing number of options with new drugs and new combinations thereof for SCLC.

A flexible MHC class I multimer loading system for large-scale detection of antigen-specific T cells

Luimstra et al. describe a temperature-mediated peptide exchange method for generating many different epitope-specific MHC class I multimers in parallel. This simple and versatile technology allows fast and efficient production of MHC I reagents for immune monitoring of T cell responses.

Adaptive immunity is initiated by T cell recognition of specific antigens presented by major histocompatibility complexes (MHCs). MHC multimer technology has been developed for the detection, isolation, and characterization of T cells in infection, autoimmunity, and cancer. Here, we present a simple, fast, flexible, and efficient method to generate many different MHC class I (MHC I) multimers in parallel using temperature-mediated peptide exchange. We designed conditional peptides for HLA-A*02:01 and H-2K^b that form stable peptide–MHC I complexes at low temperatures, but dissociate when exposed to a defined elevated temperature. The resulting conditional MHC I complexes, either alone or prepared as ready-to-use multimers, can swiftly be loaded with peptides of choice without additional handling and within a short time frame. We demonstrate the ease and flexibility of this approach by monitoring the antiviral immune constitution in an allogeneic stem cell transplant recipient and by analyzing CD8⁺ T cell responses to viral epitopes in mice infected with lymphocytic choriomeningitis virus or cytomegalovirus.

Effector Antitumor and Regulatory T Cell Responses Influence the Development of Nonmelanoma Skin Cancer in Kidney Transplant Patients

BACKGROUND

Chronic immunosuppression promotes nonmelanocytic squamous cell carcinoma (SCC) after kidney transplantation. Adaptive and innate immunity play a key role controlling tumor growth and are influenced by different immunosuppressive agents. We hypothesized that functional impairment of tumor-specific T cell responses due to calcineurin inhibitors (CNI) could contribute to SCC development, whereas conversion to mammalian target of rapamycin inhibitors (mTOR-i) could recover this protective immune response.

METHODS

Peripheral tumor-specific T cell responses against main SCC-derived antigens using the IFN-γ enzyme-linked immunospot assay and intratumor (IT) and circulating immune phenotypes (CD4 + T, CD8 + T, CD20 + B, CD56 + NK, FOXP3 + regulatory T [Treg] cells) were explored in a cross-sectional analysis in 59 kidney transplant patients with SCC on CNI (KT-CNI-SCC) or mTOR-i (KT-mTORi-SCC), 25 nontransplants developing SCC (NoKT-SCC) and 6 healthy controls. Moreover, 25 KT-CNI-SCC were switched to mTOR-i and evaluated after 12 months.

RESULTS

Kidney transplant patients showed lower IT infiltrates and tumor-specific T cell responses than NoKT-SCC, and intratumoral and circulating FOXP3 + Treg cells were higher in KT-mTORi-SCC (P < 0.05). Tumor-specific T cell responses were significantly lower in KT-CNI-SCC than KT-mTORi-SCC and NoKT-SCC and predicted SCC relapses (area under the curve = 0.837; P < 0.05). One-year after mTOR-i conversion, a significant increase in FOXP3 + Treg cell numbers and tumor-specific T cell responses were observed, reaching similar levels than KT-mTORi-SCC and NoKT-SCC patients.

CONCLUSIONS

Tumor-specific T cell responses are strongly impaired in CNI-treated patients but recover after mTOR-i conversion, reducing SCC relapses.

Immunotherapy of cancers comes of age

INTRODUCTION

Cancer immunotherapy has evolved and is aimed at generating the efficacious therapeutic modality to enhance the specificity and power of the immune system to combat tumors. Areas covered: Current efforts in cancer immunotherapy fall into three main approaches. One approach is through the blockade of immune checkpoints, another approach is through adoptive cellular therapy, and the last approach is through vaccination. The goal of this review is to summarize the current understanding and status of cancer immunotherapy in these three categories. Expert commentary: We foresee the development of therapeutic protocols combining these approaches with each other or conventional therapies to achieve the most appropriate guideline for management of cancer.

Evaluating the Role of Interdigitated Neoadjuvant Chemotherapy and Radiation in the Management of High-Grade Soft-Tissue Sarcoma: The Johns Hopkins Experience

OBJECTIVES

High-grade soft-tissue sarcoma (STS) has a poor prognosis. The goal of this study was to review treatment outcomes of patients with high-grade STS treated with interdigitated neoadjuvant chemotherapy (CT) and radiation at our institution.

MATERIALS AND METHODS

Patients with high-grade STS (1997 to 2010) were planned for treatment with 3 cycles of neoadjuvant CT, interdigitated preoperative radiation therapy (44 Gy administered in split courses with a potential 16 Gy postoperative boost), and 3 cycles of postoperative CT. Cancer control outcomes at 3 years were analyzed.

RESULTS

Sixteen patients with high-grade STS were evaluated. Median age was 53 years, the median longest tumor diameter was 14.6 cm, and median follow-up was 33 months. All 16 patients received 2 or 3 cycles of neoadjuvant CT and all patients completed neoadjuvant RT. The estimated 3-year rate for local control was 100%, disease-free survival 62.5%, and overall survival 73.4%.

CONCLUSIONS

Patients with high-grade STS treated with interdigitated neoadjuvant CT and radiation before surgical resection had excellent rates of local control, along with disease-free survival and overall survival similar to previously published reports. This combined-modality approach continues to have a role in the treatment of patients with high-grade STS.

Ipilimumab alone or in combination with radiotherapy in metastatic castration-resistant prostate cancer: results from an open-label, multicenter phase I/II study

BACKGROUND

This phase I/II study in patients with metastatic castration-resistant prostate cancer (mCRPC) explored ipilimumab as monotherapy and in combination with radiotherapy, based on the preclinical evidence of synergistic antitumor activity between anti-CTLA-4 antibody and radiotherapy.

PATIENTS AND METHODS

In dose escalation, 33 patients (≥6/cohort) received ipilimumab every 3 weeks × 4 doses at 3, 5, or 10 mg/kg or at 3 or 10 mg/kg + radiotherapy (8 Gy/lesion). The 10-mg/kg cohorts were expanded to 50 patients (ipilimumab monotherapy, 16; ipilimumab + radiotherapy, 34). Evaluations included adverse events (AEs), prostate-specific antigen (PSA) decline, and tumor response.

RESULTS

Common immune-related AEs (irAEs) among the 50 patients receiving 10 mg/kg ± radiotherapy were diarrhea (54%), colitis (22%), rash (32%), and pruritus (20%); grade 3/4 irAEs included colitis (16%) and hepatitis (10%). One treatment-related death (5 mg/kg group) occurred. Among patients receiving 10 mg/kg ± radiotherapy, eight had PSA declines of ≥50% (duration: 3-13+ months), one had complete response (duration: 11.3+ months), and six had stable disease (duration: 2.8-6.1 months).

CONCLUSIONS

In mCRPC patients, ipilimumab 10 mg/kg ± radiotherapy suggested clinical antitumor activity with disease control and manageable AEs. Two phase III trials in mCRPC patients evaluating ipilimumab 10 mg/kg ± radiotherapy are ongoing. ClinicalTrials.gov identifier: NCT00323882.

Association of CTLA-4 polymorphisms with improved overall survival in melanoma patients treated with CTLA-4 blockade: a pilot study

CTLA-4 blockade with monoclonal antibodies can lead to cancer regression in patients with metastatic melanoma (MM). CTLA-4 gene polymorphisms may influence the response to anti-CTLA-4 antibodies although few data are available regarding this issue. We analyzed six CTLA-4 single nucleotide polymorphisms (-1661A > G, -1577G > A, -658C > T, -319C > T, +49A > G, and CT60G > A) in 14 Italian MM patients and 45 healthy subjects. We found a significant association between the -1577G/A and CT60G/A genotypes and improved overall survival (Pc < 0.006, Bonferroni corrected), further confirmed by the diplotype analysis (-1577 & CT60 GG-AA diplotype, p < 0.001). A positive trend toward an association between these genotypes and response to therapy was also observed.

Evaluation of CTLA-4 expression and relevance as a novel prognostic factor in patients with non-small cell lung cancer

The role of CTLA-4 in negative regulation of T-cell mediated immune response is particularly well established. Much less is known about its expression and function in tumour cells, and to our knowledge, no data are available on its possible impact on prognosis of NSCLC patients. We investigated CTLA-4 expression and prognostic role in 81 patients with radically resected stage I-III NSCLC. The analysis was performed by tissue microarray immunohistochemistry, and the median H-score of 20 was used as a threshold to define CTLA-4 overexpressing tumours. Correlation with standard prognostic factors was performed by using absolute and relative fold change indexes. Hazard ratios (HR) and corresponding 95% confidence limits (95% CL) were computed through the Cox model. A higher frequency of CTLA-4 overexpression (>20) was found in non-squamous than in squamous NSCLC (52.8 vs. 35.7%) and in Ki67 ≤ 15 expressing tumours, as compared to those with Ki67 > 15 (51.5 vs. 38.7%). A reduced death rate was found in CTLA-4 overexpressing tumours (HR = 0.60, 95% CL = 0.28/1.23), and a further decrease was observed when considering tumours with CTLA-4 > 20 and Ki67 ≤ 15, in comparison with tumours with CTLA-4 ≤ 20 and Ki67 > 15 (HR = 0.41; 95% CL = 0.15/1.13). Our observational and exploratory study provides a first and promising indication for an independent prognostic effect of CTLA-4 overexpression in radically resected NSCLC. We presume that this effect relies on modulation of the interaction of microscopic disease with CTLA-4-ligands expressing cells leading to NSCLC cell death.

Ipilimumab in combination with paclitaxel and carboplatin as first-line therapy in extensive-disease-small-cell lung cancer: results from a randomized, double-blind, multicenter phase 2 trial

BACKGROUND

Ipilimumab, an anti-CTLA4 monoclonal antibody, demonstrated survival benefit in melanoma with immune-related (ir) adverse events (irAEs) managed by the protocol-defined guidelines. This phase 2 study evaluated ipilimumab+paclitaxel (Taxol)/carboplatin in extensive-disease-small-cell lung cancer (ED-SCLC).

DESIGN

Patients (n=130) with chemotherapy-naïve ED-SCLC were randomized 1: 1: 1 to receive paclitaxel (175 mg/m2)/carboplatin (area under the curve=6) with either placebo (control) or ipilimumab 10 mg/kg in two alternative regimens, concurrent ipilimumab (ipilimumab+paclitaxel/carboplatin followed by placebo+paclitaxel/carboplatin) or phased ipilimumab (placebo+paclitaxel/carboplatin followed by ipilimumab+paclitaxel/carboplatin). Treatment was administered every 3 weeks for a maximum of 18 weeks (induction), followed by maintenance ipilimumab or placebo every 12 weeks. End points included progression-free survival (PFS), irPFS, best overall response rate (BORR); irBORR, overall survival (OS), and safety.

RESULTS

Phased ipilimumab, but not concurrent ipilimumab, improved irPFS versus control [HR (hazard ratio)=0.64; P=0.03]. No improvement in PFS (HR=0.93; P=0.37) or OS (HR=0.75; P=0.13) occurred. Phased ipilimumab, concurrent ipilimumab and control, respectively, were associated with median irPFS of 6.4, 5.7 and 5.3 months; median PFS of 5.2, 3.9 and 5.2 months; median OS of 12.9, 9.1 and 9.9 months. Overall rates of grade 3/4 irAEs were 17, 21 and 9% for phased ipilimumab, concurrent ipilimumab and control, respectively.

CONCLUSION

These results suggest further investigation of ipilimumab in ED-SCLC.

Immunopharmacologic response of patients with B-lineage acute lymphoblastic leukemia to continuous infusion of T cell-engaging CD19/CD3-bispecific BiTE antibody blinatumomab

T cell-engaging CD19/CD3-bispecific BiTE Ab blinatumomab has shown an 80% complete molecular response rate and prolonged leukemia-free survival in patients with minimal residual B-lineage acute lymphoblastic leukemia (MRD(+) B-ALL). Here, we report that lymphocytes in all patients of a phase 2 study responded to continuous infusion of blinatumomab in a strikingly similar fashion. After start of infusion, B-cell counts dropped to < 1 B cell/μL within an average of 2 days and remained essentially undetectable for the entire treatment period. By contrast, T-cell counts in all patients declined to a nadir within < 1 day and recovered to baseline within a few days. T cells then expanded and on average more than doubled over baseline within 2-3 weeks under continued infusion of blinatumomab. A significant percentage of reappearing CD8(+) and CD4(+) T cells newly expressed activation marker CD69. Shortly after start of infusion, a transient release of cytokines dominated by IL-10, IL-6, and IFN-γ was observed, which no longer occurred on start of a second treatment cycle. The response of lymphocytes in leukemic patients to continuous infusion of blinatumomab helps to better understand the mode of action of this and other globally T cell-engaging Abs. The trial is registered with www.clinicaltrials.gov identifier NCT00560794.

Management of melanomas in children and young adults

Melanoma is rare in children and young adults. The incidence is rising yearly in this population. The clinical features of the disease in the pediatric population have been well documented through single-institution experiences and population-based analyses. Still, our understanding of the etiologic factors in the majority of children remains unclear, and diagnosis of melanoma remains challenging in certain cases. Because of its rarity, the staging, management and treatment of melanoma in this population is adopted from adult guidelines. In this review, we provide information on the epidemiology, clinical presentation, staging, prognosis and management of melanoma in children and young adults.

Ipilimumab in combination with paclitaxel and carboplatin as first-line treatment in stage IIIB/IV non-small-cell lung cancer: results from a randomized, double-blind, multicenter phase II study

PURPOSE

Ipilimumab, which is an anti-cytotoxic T-cell lymphocyte-4 monoclonal antibody, showed a survival benefit in melanoma with adverse events (AEs) managed by protocol-defined guidelines. A phase II study in lung cancer assessed the activity of ipilimumab plus paclitaxel and carboplatin.

PATIENTS AND METHODS

Patients (N = 204) with chemotherapy-naive non-small-cell lung cancer (NSCLC) were randomly assigned 1:1:1 to receive paclitaxel (175 mg/m(2)) and carboplatin (area under the curve, 6) with either placebo (control) or ipilimumab in one of the following two regimens: concurrent ipilimumab (four doses of ipilimumab plus paclitaxel and carboplatin followed by two doses of placebo plus paclitaxel and carboplatin) or phased ipilimumab (two doses of placebo plus paclitaxel and carboplatin followed by four doses of ipilimumab plus paclitaxel and carboplatin).Treatment was administered intravenously every 3 weeks for ≤ 18 weeks (induction). Eligible patients continued ipilimumab or placebo every 12 weeks as maintenance therapy. Response was assessed by using immune-related response criteria and modified WHO criteria. The primary end point was immune-related progression-free survival (irPFS). Other end points were progression-free survival (PFS), best overall response rate (BORR), immune-related BORR (irBORR), overall survival (OS), and safety.

RESULTS

The study met its primary end point of improved irPFS for phased ipilimumab versus the control (hazard ratio [HR], 0.72; P = .05), but not for concurrent ipilimumab (HR, 0.81; P = .13). Phased ipilimumab also improved PFS according to modified WHO criteria (HR, 0.69; P = .02). Phased ipilimumab, concurrent ipilimumab, and control treatments were associated with a median irPFS of 5.7, 5.5, and 4.6 months, respectively, a median PFS of 5.1, 4.1, and 4.2 months, respectively, an irBORR of 32%, 21% and 18%, respectively, a BORR of 32%, 21% and 14%, respectively, and a median OS of 12.2, 9.7, and 8.3 months. Overall rates of grade 3 and 4 immune-related AEs were 15%, 20%, and 6% for phased ipilimumab, concurrent ipilimumab, and the control, respectively. Two patients (concurrent, one patient; control, one patient) died from treatment-related toxicity.

CONCLUSION

Phased ipilimumab plus paclitaxel and carboplatin improved irPFS and PFS, which supports additional investigation of ipilimumab in NSCLC.

Targeting the tumor microenvironment by immunotherapy: part 2

Cancer therapy was traditionally centered on the neoplastic cells. This included mainly surgery, radiation, and chemotherapy, in some cases hormone therapy and to a lesser extent immunotherapy – all traditionally targeted to the highly proliferating mutated tumor cells. In view of our present understanding of the powerfull influence of the tumor microenvironment (TME) on cancer behavior and response – and lack of response – to treatment, this previously ignored constituent of cancer now has to be considered as an important, even indispensable target for therapy. The TME may be targeted both to its immune and to its nonimmune components. The various immune evasion elements of the TME should be targeted as well.

Improving cancer immunotherapy by targeting tumor-induced immune suppression

The status of a host's immune response influences both the development and progression of a malignancy such that immune responses can have both pro- and anti-tumorigenic effects. Cancer immunotherapy is a form of treatment that aims to improve the ability of a cancer-bearing individual to reject the tumor immunologically. However, antitumor immunity elicited by the host or by immunotherapeutic strategies, can be actively attenuated by mechanisms that limit the strength and/or duration of immune responses, including the presence of immunoregulatory cell types or the production of immunosuppressive factors. As our knowledge of tumor-induced immune suppression increases, it has become obvious that these mechanisms are probably a major barrier to effective therapy. The identification of multiple mechanisms of tumor-induced immune suppression also provides a range of novel targets for new cancer therapies. Given the vital role that a host's immune response is known to play in cancer progression, therapies that target immune suppressive mechanisms have the potential to enhance anticancer immune responses thus leading to better immune surveillance and the limitation of tumor escape. In this review, mechanisms of tumor-associated immune suppression have been divided into four forms that we have designated as (1) regulatory cells; (2) cytokines/chemokines; (3) T cell tolerance/exhaustion and (4) metabolic. We discuss select mechanisms representing each of these forms of immunosuppression that have been shown to aid tumors in evading host immune surveillance and overview therapeutic strategies that have been recently devised to "suppress these suppressors."

Antiangiogenic therapies: is VEGF-A inhibition alone enough?

Although available targeted therapies provide some clinical efficacy, a need remains for antiangiogenic therapies with alternative mechanisms in order to provide better outcomes and the ability to circumvent resistance. Inhibition of multiple VEGF targets may produce enhanced efficacy and more durable responses through synergistic effects, and prevent the development of escape mechanisms. Inhibition of VEGF-A, VEGF-C and VEGF-D with broad-spectrum VEGF receptor-2 (VEGFR-2) inhibitors, such as the novel protein therapeutic CT-322, may result in increased efficacy and prevent or delay acquired resistance and metastatic spread often seen with VEGF-A inhibition alone. Therefore, panoramic inhibition of VEGFR-2 may be a better approach to more effective antiangiogenic therapy. This article focuses on pivotal data on VEGF/VEGFR inhibitors currently in use, as well as newer agents in development.