Oncolytic herpes simplex virus armed with a bacterial GBP1 degrader improves antitumor activity

Oncolytic viruses (OVs) encoding various transgenes are being evaluated for cancer immunotherapy. Diverse factors such as cytokines, immune checkpoint inhibitors, tumor-associated antigens, and T cell engagers have been exploited as transgenes. These modifications are primarily aimed to reverse the immunosuppressive tumor microenvironment. By contrast, antiviral restriction factors that inhibit the replication of OVs and result in suboptimal oncolytic activity have received far less attention. Here, we report that guanylate-binding protein 1 (GBP1) is potently induced during HSV-1 infection and restricts HSV-1 replication. Mechanistically, GBP1 remodels cytoskeletal organization to impede nuclear entry of HSV-1 genome. Previous studies have established that IpaH9.8, a bacterial E3 ubiquitin ligase, targets GBPs for proteasomal degradation. We therefore engineered an oncolytic HSV-1 to express IpaH9.8 and found that the modified OV effectively antagonized GBP1, replicated to a higher titer in vitro and showed superior antitumor activity in vivo. Our study features a strategy for improving the replication of OVs via targeting a restriction factor and achieving promising therapeutic efficacy.

Neoadjuvant treatment for stage III and IV cutaneous melanoma

BACKGROUND

Cutaneous melanoma is amongst the most aggressive of all skin cancers. Neoadjuvant treatment is a form of induction therapy, given to shrink a cancerous tumour prior to the main treatment (usually surgery). The purpose is to improve survival and surgical outcomes. This review systematically appraises the literature investigating the use of neoadjuvant treatment for stage III and IV cutaneous melanoma.

OBJECTIVES

To assess the effects of neoadjuvant treatment in adults with stage III or stage IV melanoma according to the seventh edition American Joint Committee on Cancer (AJCC) staging system.

SEARCH METHODS

We searched the following databases up to 10 August 2021 inclusive: Cochrane Skin Specialised Register, CENTRAL, MEDLINE, Embase, LILACS and four trials registers, together with reference checking and contact with study authors to identify additional studies. We also handsearched proceedings from specific conferences from 2016 to 2020 inclusive.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of people with stage III and IV melanoma, comparing neoadjuvant treatment strategies (using targeted treatments, immunotherapies, radiotherapy, topical treatments or chemotherapy) with any of these agents or current standard of care (SOC), were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Primary outcomes were overall survival (OS) and adverse effects (AEs). Secondary outcomes included time to recurrence (TTR), quality of life (QOL), and overall response rate (ORR). We used GRADE to evaluate the certainty of the evidence.

MAIN RESULTS

We included eight RCTs involving 402 participants. Studies enrolled adults, mostly with stage III melanoma, investigated immunotherapies, chemotherapy, or targeted treatments, and compared these with surgical excision with or without adjuvant treatment. Duration of follow-up and therapeutic regimens varied, which, combined with heterogeneity in the population and definitions of the endpoints, precluded meta-analysis of all identified studies. We performed a meta-analysis including three studies. We are very uncertain if neoadjuvant treatment increases OS when compared to no neoadjuvant treatment (hazard ratio (HR) 0.43, 95% confidence interval (CI) 0.15 to 1.21; 2 studies, 171 participants; very low-certainty evidence). Neoadjuvant treatment may increase the rate of AEs, but the evidence is very uncertain (26% versus 16%, risk ratio (RR) 1.58, 95% CI 0.97 to 2.55; 2 studies, 162 participants; very low-certainty evidence). We are very uncertain if neoadjuvant treatment increases TTR (HR 0.51, 95% CI 0.22 to 1.17; 2 studies, 171 participants; very low-certainty evidence). Studies did not report ORR as a comparative outcome or measure QOL data. We are very uncertain whether neoadjuvant targeted treatment with dabrafenib and trametinib increases OS (HR 0.28, 95% CI 0.03 to 2.25; 1 study, 21 participants; very low-certainty evidence) or TTR (HR 0.02, 95% CI 0.00 to 0.22; 1 study, 21 participants; very low-certainty evidence) when compared to surgery. The study did not report comparative rates of AEs and overall response, and did not measure QOL. We are very uncertain if neoadjuvant immunotherapy with talimogene laherparepvec increases OS when compared to no neoadjuvant treatment (HR 0.49, 95% CI 0.15 to 1.64; 1 study, 150 participants, very low-certainty evidence). It may have a higher rate of AEs, but the evidence is very uncertain (16.5% versus 5.8%, RR 2.84, 95% CI 0.96 to 8.37; 1 study, 142 participants; very low-certainty evidence). We are very uncertain if it increases TTR (HR 0.75, 95% CI 0.31 to 1.79; 1 study, 150 participants; very low-certainty evidence). The study did not report comparative ORRs or measure QOL. OS was not reported for neoadjuvant immunotherapy (combined ipilimumab and nivolumab) when compared to the combination of ipilimumab and nivolumab as adjuvant treatment. There may be little or no difference in the rate of AEs between these treatments (9%, RR 1.0, 95% CI 0.75 to 1.34; 1 study, 20 participants; low-certainty evidence). The study did not report comparative ORRs or measure TTR and QOL. Neoadjuvant immunotherapy (combined ipilimumab and nivolumab) likely results in little to no difference in OS when compared to neoadjuvant nivolumab monotherapy (P = 0.18; 1 study, 23 participants; moderate-certainty evidence). It may increase the rate of AEs, but the certainty of this evidence is very low (72.8% versus 8.3%, RR 8.73, 95% CI 1.29 to 59; 1 study, 23 participants); this trial was halted early due to observation of disease progression preventing surgical resection in the monotherapy arm and the high rate of treatment-related AEs in the combination arm. Neoadjuvant combination treatment may lead to higher ORR, but the evidence is very uncertain (72.8% versus 25%, RR 2.91, 95% CI 1.02 to 8.27; 1 study, 23 participants; very low-certainty evidence). It likely results in little to no difference in TTR (P = 0.19; 1 study, 23 participants; low-certainty evidence). The study did not measure QOL. OS was not reported for neoadjuvant immunotherapy (combined ipilimumab and nivolumab) when compared to neoadjuvant sequential immunotherapy (ipilimumab then nivolumab). Only Grade 3 to 4 immune-related AEs were reported; fewer were reported with combination treatment, and the sequential treatment arm closed early due to a high incidence of severe AEs. The neoadjuvant combination likely results in a higher ORR compared to sequential neoadjuvant treatment (60.1% versus 42.3%, RR 1.42, 95% CI 0.87 to 2.32; 1 study, 86 participants; low-certainty evidence). The study did not measure TTR and QOL. No data were reported on OS, AEs, TTR, or QOL for the comparison of neoadjuvant interferon (HDI) plus chemotherapy versus neoadjuvant chemotherapy. Neoadjuvant HDI plus chemotherapy may have little to no effect on ORR, but the evidence is very uncertain (33% versus 22%, RR 1.75, 95% CI 0.62 to 4.95; 1 study, 36 participants; very low-certainty evidence).

AUTHORS' CONCLUSIONS

We are uncertain if neoadjuvant treatment increases OS or TTR compared with no neoadjuvant treatment, and it may be associated with a slightly higher rate of AEs. There is insufficient evidence to support the use of neoadjuvant treatment in clinical practice. Priorities for research include the development of a core outcome set for neoadjuvant trials that are adequately powered, with validation of pathological and radiological responses as intermediate endpoints, to investigate the relative benefits of neoadjuvant treatment compared with adjuvant treatment with immunotherapies or targeted therapies.

Considerations for Clinical Translation of MG1 Maraba Virus

Oncolytic viral immunotherapy based on the MG1 Maraba platform has undergone extensive preclinical evaluation, resulting in the advancement of two programs into clinical trials. MG1 Maraba encoding tumor antigens (tumor associated antigens or viral antigens) are used to boost antitumor immunity, while MG1 Maraba infects tumors, causes oncolysis and transforms the tumor microenvironment. An overview of MG1 Maraba clinical development is outlined here, along with general considerations relating to the design of clinical trials for complex biologic products such as oncolytic viral immunotherapies. These include choice of patient population, optimized treatment regimen, and endpoints which provide early signals of activity and inform the late-stage development path of these agents with novel mechanisms of action.

Systemic Therapies for Advanced Melanoma

The incidence of metastatic melanoma continues to increase each decade. Although surgical treatment is often curative for localized stage I and stage II disease, the median survival for patients with distant metastases is less than 1 year. The last 2 decades have witnessed a breakthrough in therapeutic options with the development of immune checkpoint inhibitors, small molecule targeted therapy, and oncolytic viral therapy. This article provides an overview of the treatment options available for advanced melanoma, including chemotherapy, targeted therapy, immunotherapy, interleukin-2, and oncolytic viral agents.

The Current Status and Future Prospects of Oncolytic Viruses in Clinical Trials against Melanoma, Glioma, Pancreatic, and Breast Cancers

Oncolytic viral therapy has been accepted as a standard immunotherapy since talimogene laherparepvec (T-VEC, Imlygic^®) was approved by the Food and Drug Administration (FDA) and European Medicines Agency (EMA) for melanoma treatment in 2015. Various oncolytic viruses (OVs), such as HF10 (Canerpaturev—C-REV) and CVA21 (CAVATAK), are now actively being developed in phase II as monotherapies, or in combination with immune checkpoint inhibitors against melanoma. Moreover, in glioma, several OVs have clearly demonstrated both safety and a promising efficacy in the phase I clinical trials. Additionally, the safety of several OVs, such as pelareorep (Reolysin^®), proved their safety and efficacy in combination with paclitaxel in breast cancer patients, but the outcomes of OVs as monotherapy against breast cancer have not provided a clear therapeutic strategy for OVs. The clinical trials of OVs against pancreatic cancer have not yet demonstrated efficacy as either monotherapy or as part of combination therapy. However, there are several oncolytic viruses that have successfully proved their efficacy in different preclinical models. In this review, we mainly focused on the oncolytic viruses that transitioned into clinical trials against melanoma, glioma, pancreatic, and breast cancers. Hence, we described the current status and future prospects of OVs clinical trials against melanoma, glioma, pancreatic, and breast cancers.

Intralesional treatment for advanced melanoma: what's on the horizon?

Advances in treatment of melanoma with systemic immunotherapies continue, with promising findings for anti-PD-1 agents combined with ipilimumab. Still, an unmet need persists because of populations ineligible for systemic immunotherapies, incomplete cure/response rates, toxicities and extreme costs. Also, potential for effective use of intralesional therapies remains, especially for local regional disease, but also for benefits of local ablation and adjuvant systemic host tumor-specific responses. Clinical trials of T-VEC, PV-10, CAVATAK and electroporation with plasmid IL-12 have demonstrated favorable, durable responses. Initial experience combining T-VEC, the agent furthest along in testing, with ipilimumab revealed higher complete and overall response rates than with either agent alone. Intralesional therapies may offer a treatment tool in the growing therapeutic armamentarium against this lethal disease.

In situ vaccination: Cancer immunotherapy both personalized and off-the-shelf

As cancer immunotherapy continues to benefit from novel approaches which cut immune 'brake pedals' (e.g. anti-PD1 and anti-CTLA4 antibodies) and push immune cell gas pedals (e.g. IL2, and IFNα) there will be increasing need to develop immune 'steering wheels' such as vaccines to guide the immune system specifically toward tumor associated antigens. Two primary hurdles in cancer vaccines have been: identification of universal antigens to be used in 'off-the-shelf' vaccines for common cancers, and 2) logistical hurdles of ex vivo production of individualized whole tumor cell vaccines. Here we summarize approaches using 'in situ vaccination' in which intratumoral administration of off-the-shelf immunomodulators have been developed to specifically induce (or amplify) T cell responses to each patient's individual tumor. Clinical studies have confirmed the induction of systemic immune and clinical responses to such approaches and preclinical models have suggested ways to further potentiate the translation of in situ vaccine trials for our patients.

Long term survival with cytotoxic T lymphocyte-associated antigen 4 blockade using tremelimumab

PURPOSE

One of the hallmarks of cancer immunotherapy is the long duration of responses, evident with cytokines like interleukin-2 or a variety of cancer vaccines. However, there is limited information available on very long term outcomes of patients treated with anti-cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) antibodies. Tremelimumab is an anti-CTLA-4 antibody of immunoglobulin G2 (IgG2) isotype initially tested in patients with advanced melanoma over 12 years ago.

METHODS

We reviewed the outcomes of patients with advanced melanoma enrolled in four phase 1 and 2 tremelimumab trials at two sites to determine response rates and long-term survival.

RESULTS

A total of 143 patients were enrolled at two institutions from 2002 to 2008. Tremelimumab administration varied between a single dose of 0.01 mg/kg and 15 mg/kg every 3 months. Median overall survival was 13 months (95% confidence interval (CI), 10-16.6), ranging from less than a month to 12+ years. An objective response rate of 15.6% was observed, with median duration of response of 6.5 years, range of 3-136+ months. The Kaplan-Meier estimated 5 year survival rate was 20% (95% CI, 13-26%), with 10 and 12.5 year survival rates of 16% (95% CI, 9-23%).

CONCLUSIONS

CTLA-4 blockade with tremelimumab can lead to very long duration of objective anti-tumour responses beyond 12 years.

Adapted ECHO-7 virus Rigvir immunotherapy (oncolytic virotherapy) prolongs survival in melanoma patients after surgical excision of the tumour in a retrospective study

An oncolytic, nonpathogenic ECHO-7 virus adapted for melanoma that has not been genetically modified (Rigvir) is approved and registered for virotherapy, an active and specific immunotherapy, in Latvia since 2004. The present retrospective study was carried out to determine the effectiveness of Rigvir in substage IB, IIA, IIB and IIC melanoma patients on time to progression and overall survival. White patients (N=79) who had undergone surgical excision of the primary melanoma tumour were included in this study. All patients were free from disease after surgery and classified into substages IB, IIA, IIB and IIC. Circulating levels of clinical chemistry parameters were recorded. Survival was analysed by Cox regression. Rigvir significantly (P<0.05) prolonged survival in substage IB-IIC melanoma patients following surgery compared with patients who were under observation (according to current guidelines). The hazard ratio for patients under observation versus treated with Rigvir was statistically significantly different: hazard ratio 6.27 for all, 4.39 for substage IIA-IIB-IIC and 6.57 for substage IIB-IIC patients. The follow-up period was not statistically different between both treatment groups. These results indicate that the patients treated with Rigvir had a 4.39-6.57-fold lower mortality than those under observation. In this study, there was no untoward side effect or discontinuation of Rigvir treatment. Safety assessment of adverse events graded according to NCI CTCAE did not show any value above grade 2 in Rigvir-treated patients. In conclusion, Rigvir significantly prolongs survival in early-stage melanoma patients without any side effect.

Talimogene Laherparepvec Improves Durable Response Rate in Patients With Advanced Melanoma

Purpose

Talimogene laherparepvec (T-VEC) is a herpes simplex virus type 1–derived oncolytic immunotherapy designed to selectively replicate within tumors and produce granulocyte macrophage colony-stimulating factor (GM-CSF) to enhance systemic antitumor immune responses. T-VEC was compared with GM-CSF in patients with unresected stage IIIB to IV melanoma in a randomized open-label phase III trial.

Patients and Methods

Patients with injectable melanoma that was not surgically resectable were randomly assigned at a two-to-one ratio to intralesional T-VEC or subcutaneous GM-CSF. The primary end point was durable response rate (DRR; objective response lasting continuously ≥ 6 months) per independent assessment. Key secondary end points included overall survival (OS) and overall response rate.

Results

Among 436 patients randomly assigned, DRR was significantly higher with T-VEC (16.3%; 95% CI, 12.1% to 20.5%) than GM-CSF (2.1%; 95% CI, 0% to 4.5%]; odds ratio, 8.9; P < .001). Overall response rate was also higher in the T-VEC arm (26.4%; 95% CI, 21.4% to 31.5% v 5.7%; 95% CI, 1.9% to 9.5%). Median OS was 23.3 months (95% CI, 19.5 to 29.6 months) with T-VEC and 18.9 months (95% CI, 16.0 to 23.7 months) with GM-CSF (hazard ratio, 0.79; 95% CI, 0.62 to 1.00; P = .051). T-VEC efficacy was most pronounced in patients with stage IIIB, IIIC, or IVM1a disease and in patients with treatment-naive disease. The most common adverse events (AEs) with T-VEC were fatigue, chills, and pyrexia. The only grade 3 or 4 AE occurring in ≥ 2% of T-VEC–treated patients was cellulitis (2.1%). No fatal treatment-related AEs occurred.

Conclusion

T-VEC is the first oncolytic immunotherapy to demonstrate therapeutic benefit against melanoma in a phase III clinical trial. T-VEC was well tolerated and resulted in a higher DRR (P < .001) and longer median OS (P = .051), particularly in untreated patients or those with stage IIIB, IIIC, or IVM1a disease. T-VEC represents a novel potential therapy for patients with metastatic melanoma.

Safety and immunologic correlates of Melanoma GVAX, a GM-CSF secreting allogeneic melanoma cell vaccine administered in the adjuvant setting

Background

Limited adjuvant treatment options exist for patients with high-risk surgically resected melanoma. This first-in-human study investigated the safety, tolerability and immunologic correlates of Melanoma GVAX, a lethally irradiated granulocyte–macrophage colony stimulating factor (GM-CSF)-secreting allogeneic whole-cell melanoma vaccine, administered in the adjuvant setting.

Methods

Patients with stage IIB-IV melanoma were enrolled following complete surgical resection. Melanoma GVAX was administered intradermally once every 28 days for four cycles, at 5E7 cells/cycle (n = 3), 2E8 cells/cycle (n = 9), or 2E8 cells/cycle preceded by cyclophosphamide 200 mg/m² to deplete T regulatory cells (Tregs; n = 8). Blood was collected before each vaccination and at 4 and 6 months after treatment initiation for immunologic studies. Vaccine injection site biopsies and additional blood samples were obtained 2 days after the 1st and 4th vaccines.

Results

Among 20 treated patients, 18 completed 4 vaccinations. Minimal treatment-related toxicity was observed. One patient developed vitiligo and patches of white hair during the treatment and follow-up period. Vaccine site biopsies demonstrated complex inflammatory infiltrates, including significant increases in eosinophils and PD-1+ lymphocytes from cycle 1 to cycle 4 (P < 0.05). Serum GM-CSF concentrations increased significantly in a dose-dependent manner 48 h after vaccination (P = 0.0086), accompanied by increased numbers of activated circulating monocytes (P < 0.0001) and decreased percentages of myeloid-derived suppressor cells among monocytes (CD14+ , CD11b+ , HLA-DR low or negative; P = 0.002). Cyclophosphamide did not affect numbers of circulating Tregs. No significant changes in anti-melanoma immunity were observed in peripheral T cells by interferon-gamma ELIPSOT, or immunoglobulins by serum Western blotting.

Conclusion

Melanoma GVAX was safe and tolerable in the adjuvant setting. Pharmacodynamic testing revealed complex vaccine site immune infiltrates and an immune-reactive profile in circulating monocytic cell subsets. These findings support the optimization of Melanoma GVAX with additional monocyte and dendritic cell activators, and the potential development of combinatorial treatment regimens with synergistic agents.

Trial registration: NCT01435499

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-015-0572-3) contains supplementary material, which is available to authorized users.

The Role of Regional Therapies for in-Transit Melanoma in the Era of Improved Systemic Options

The incidence of melanoma has been increasing at a rapid rate, with 4%–11% of all melanoma recurrences presenting as in-transit disease. Treatments for in-transit melanoma of the extremity are varied and include surgical excision, lesional injection, regional techniques and systemic therapies. Excision to clear margins is preferred; however, in cases of widespread disease, this may not be practical. Historically, intralesional therapies were generally not curative and were often used for palliation or as adjuncts to other therapies, but recent advances in oncolytic viruses may change this paradigm. Radiation as a regional therapy can be quite locally toxic and is typically relegated to disease control and symptom relief in patients with limited treatment options. Regional therapies such as isolated limb perfusion and isolated limb infusion are older therapies, but offer the ability to treat bulky disease for curative intent with a high response rate. These techniques have their associated toxicities and can be technically challenging. Historically, systemic therapy with chemotherapies and biochemotherapies were relatively ineffective and highly toxic. With the advent of novel immunotherapeutic and targeted small molecule agents for the treatment of metastatic melanoma, the armamentarium against in-transit disease has expanded. Given the multitude of options, many different combinations and sequences of therapies can be offered to patients with in-transit extremity melanoma in the contemporary era. Reported response and survival rates of the varied treatments may offer valuable information regarding treatment decisions for patients with in-transit melanoma and provide rationale for these decisions.

Treatment of melanoma with a serotype 5/3 chimeric oncolytic adenovirus coding for GM-CSF: Results in vitro, in rodents and in humans

Metastatic melanoma is refractory to irradiation and chemotherapy, but amenable to immunological approaches such as immune-checkpoint-inhibiting antibodies or adoptive cell therapies. Oncolytic virus replication is an immunogenic phenomenon, and viruses can be armed with immunostimulatory molecules. Therefore, oncolytic immuno-virotherapy of malignant melanoma is an appealing approach, which was recently validated by a positive phase 3 trial. We investigated the potency of oncolytic adenovirus Ad5/3-D24-GMCSF on a panel of melanoma cell lines and animal models, and summarized the melanoma-specific human data from the Advanced Therapy Access Program (ATAP). The virus effectively eradicated human melanoma cells in vitro and subcutaneous SK-MEL-28 melanoma xenografts in nude mice when combined with low-dose cyclophosphamide. Furthermore, virally-expressed granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulated the differentiation of human monocytes into macrophages. In contrast to human cells, RPMI 1846 hamster melanoma cells exhibited no response to oncolytic viruses and the chimeric 5/3 fiber failed to increase the efficacy of transduction, suggesting limited utility of the hamster model in the context of viruses with this capsid. In ATAP, treatments appeared safe and well-tolerated. Four out of nine melanoma patients treated were evaluable for possible therapy benefit with modified RECIST criteria: one patient had minor response, two had stable disease, and one had progressive disease. Two patients were alive at 559 and 2,149 days after treatment. Ad5/3-D24-GMCSF showed promising efficacy in preclinical studies and possible antitumor activity in melanoma patients refractory to other forms of therapy. This data supports continuing the clinical development of oncolytic adenoviruses for treatment of malignant melanoma.

Beyond CTLA-4: novel immunotherapy strategies for metastatic melanoma

The treatment of metastatic melanoma is rapidly evolving. The discovery of BRAF and MEK inhibitors was an important milestone. Unfortunately, although response rates are high, disease progression is universal. Despite the success of IL-2 and adjuvant IFL-α2b, these two agents remained the only approved immunotherapy approaches. In recent years, the use of immunotherapy has drawn attention with the recognition of the mechanisms of tumor immune evasion. Blockade of these mechanisms may improve outcomes. However, the potential adverse events, the optimal use of these modalities, the high cost and the absence of predictive markers remain unmet challenges. Herein, we review the immunotherapy strategies in melanoma, either approved or under evaluation, and present the relevant data concerning their efficacy and safety.

Immune checkpoint modulation: rational design of combination strategies

Immune recognition and elimination of malignant cells require a series of steps orchestrated by the innate and the adaptive arms of the immune system. The majority of tumors have evolved mechanisms that allow for successful evasion of these immune responses. Recognition of these evasive processes led to the development of immunotherapeutic antibodies targeting the co-stimulatory and co-inhibitory receptors on T cells, with the goal of enhancement of T cell activation or reversal of tumor-induced T cell inhibition. Several of these agents, such as antibodies targeting cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed death receptor 1 (PD-1) have already demonstrated significant promise in clinical trials. Clinical benefit of these antibodies as single agents, however, has been limited to a subset of patients and has not been observed in all tumor types. These limitations call for the development of rational combination strategies aiming to extend therapeutic benefit to a broader range of patients. These include: 1) modalities that enhance antigen presentation, such as radiation, cryotherapy, chemotherapy, targeted agents, vaccines, toll-like receptor (TLR) agonists, type I interferon, and oncolytic viruses; 2) additional agents aiming to reverse T cell dysfunction, such as other immune checkpoint inhibitors; and 3) agents targeting other immune inhibitory mechanisms, such as inhibitors of indoleamine dioxygenase (IDO), regulatory T cells, and myeloid-derived suppressor cells (MDSCs). It is becoming increasingly evident that the efficacy of specific combinations will likely not be universal and that the choice of a treatment modality may need to be tailored to fit the needs of each individual patient.

The New Era of Cancer Immunotherapy: Manipulating T-Cell Activity to Overcome Malignancy

Using the immune system to control cancer has been investigated for over a century. Yet it is only over the last several years that therapeutic agents acting directly on the immune system have demonstrated improved overall survival for cancer patients in phase III clinical trials. Furthermore, it appears that some patients treated with such agents have been cured of metastatic cancer. This has led to increased interest and acceleration in the rate of progress in cancer immunotherapy. Most of the current immunotherapeutic success in cancer treatment is based on the use of immune-modulating antibodies targeting critical checkpoints (CTLA-4 and PD-1/PD-L1). Several other immune-modulating molecules targeting inhibitory or stimulatory pathways are being developed. The combined use of these medicines is the subject of intense investigation and holds important promise. Combination regimens include those that incorporate targeted therapies that act on growth signaling pathways, as well as standard chemotherapy and radiation therapy. In fact, these standard therapies have intrinsic immune-modulating properties that can support antitumor immunity. In the years ahead, adoptive T-cell therapy will also be an important part of treatment for some cancer patients. Other areas which are regaining interest are the use of oncolytic viruses that immunize patients against their own tumors and the use of vaccines against tumor antigens. Immunotherapy has demonstrated unprecedented durability in controlling multiple types of cancer and we expect its use to continue expanding rapidly.