New hopes for the breast cancer treatment: perspectives on the oncolytic virus therapy.

Oncolytic virus (OV) therapy has emerged as a promising frontier in cancer treatment, especially for solid tumours. While immunotherapies like immune checkpoint inhibitors and CAR-T cells have demonstrated impressive results, their limitations in inducing complete tumour regression have spurred researchers to explore new approaches targeting tumours resistant to current immunotherapies. OVs, both natural and genetically engineered, selectively replicate within cancer cells, inducing their lysis while sparing normal tissues. Recent advancements in clinical research and genetic engineering have enabled the development of targeted viruses that modify the tumour microenvironment, triggering anti-tumour immune responses and exhibiting synergistic effects with other cancer therapies. Several OVs have been studied for breast cancer treatment, including adenovirus, protoparvovirus, vaccinia virus, reovirus, and herpes simplex virus type I (HSV-1). These viruses have been modified or engineered to enhance their tumour-selective replication, reduce toxicity, and improve oncolytic properties.Newer generations of OVs, such as Oncoviron and Delta-24-RGD adenovirus, exhibit heightened replication selectivity and enhanced anticancer effects, particularly in breast cancer models. Clinical trials have explored the efficacy and safety of various OVs in treating different cancers, including melanoma, nasopharyngeal carcinoma, head and neck cancer, and gynecologic malignancies. Notably, Talimogene laherparepvec (T-VEC) and Oncorine have. been approved for advanced melanoma and nasopharyngeal carcinoma, respectively. However, adverse effects have been reported in some cases, including flu-like symptoms and rare instances of severe complications such as fistula formation. Although no OV has been approved specifically for breast cancer treatment, ongoing preclinical clinical trials focus on four groups of viruses. While mild adverse effects like low-grade fever and nausea have been observed, the effectiveness of OV monotherapy in breast cancer remains insufficient. Combination strategies integrating OVs with chemotherapy, radiotherapy, or immunotherapy, show promise in improving therapeutic outcomes. Oncolytic virus therapy holds substantial potential in breast cancer treatment, demonstrating safety in trials. Multi-approach strategies combining OVs with conventional therapies exhibit more promising therapeutic effects than monotherapy, signalling a hopeful future for OV-based breast cancer treatments.

Chowaniec H ，Ślubowska A ，Mroczek M ，Borowczyk M ，Braszka M ，Dworacki G ，Dobosz P ，Wichtowski M ... -  《Frontiers in Immunology》

Recent advances in oncolytic virus-based cancer therapy.

Administration of oncolytic viruses (OVs) is an emerging anticancer strategy that exploits the lytic nature of viral replication to enhance the killing of malignant cells. OVs can be used as tools to directly induce cancer cell death and to trigger local and/or systemic immune responses to metastatic cancer in vivo. The effectiveness of OV therapy was initially highlighted by the clinical use of the genetically modified herpes virus, talimogene laherparepvec, for melanoma therapy. A number of OVs are now being evaluated as potential treatments for cancer in clinical trials. In spite of being engineered to specifically target tumor cells, the safety and off-target effects of OV therapy are a concern. The potential safety concerns of OVs are highlighted by current clinical trial criteria, which exclude individuals harbouring other viral infections and people who are immunocompromised. Despite the potential for adverse effects, clinical trials to date revealed relatively minimal adverse immune-related effects, such as fever. With advances in our understanding of virus replication cycles, several novel OVs have emerged. Reverse genetic systems have facilitated the insertion of anticancer genes into a range of OVs to further enhance their tumor-killing capacity. In this review, we highlight the recent advances in OV therapy for a range of human cancers in in vitro and in in vivo animal studies. We further discuss the future of OVs as a therapeutic strategy for a range of life-threatening cancers.

Fu LQ ，Wang SB ，Cai MH ，Wang XJ ，Chen JY ，Tong XM ，Chen XY ，Mou XZ ... -  《-》

Intratumoral Immunotherapy-Update 2019.

Intratumoral immunotherapies aim to trigger local and systemic immunologic responses via direct injection of immunostimulatory agents with the goal of tumor cell lysis, followed by release of tumor-derived antigens and subsequent activation of tumor-specific effector T cells. In 2019, a multitude of intratumoral immunotherapies with varied mechanisms of action, including nononcolytic viral therapies such as PV-10 and toll-like receptor 9 agonists and oncolytic viral therapies such as CAVATAK, Pexa-Vec, and HF10, have been extensively evaluated in clinical trials and demonstrated promising antitumor activity with tolerable toxicities in melanoma and other solid tumor types. Talimogene laherparepvec (T-VEC), a genetically modified herpes simplex virus type 1-based oncolytic immunotherapy, is the first oncolytic virus approved by the U.S. Food and Drug Administration for the treatment of unresectable melanoma recurrent after initial surgery. In patients with unresectable metastatic melanoma, T-VEC demonstrated a superior durable response rate (continuous complete response or partial response lasting ≥6 months) over subcutaneous GM-CSF (16.3% vs. 2.1%; p < .001). Responses were seen in both injected and uninjected lesions including visceral lesions, suggesting a systemic antitumor response. When combined with immune checkpoint inhibitors, T-VEC significantly improved response rates compared with single agent; similar results were seen with combinations of checkpoint inhibitors and other intratumoral therapies such as CAVATAK, HF10, and TLR9 agonists. In this review, we highlight recent results from clinical trials of key intratumoral immunotherapies that are being evaluated in the clinic, with a focus on T-VEC in the treatment of advanced melanoma as a model for future solid tumor indications. IMPLICATIONS FOR PRACTICE: This review provides oncologists with the latest information on the development of key intratumoral immunotherapies, particularly oncolytic viruses. Currently, T-VEC is the only U.S. Food and Drug Administration (FDA)-approved oncolytic immunotherapy. This article highlights the efficacy and safety data from clinical trials of T-VEC both as monotherapy and in combination with immune checkpoint inhibitors. This review summarizes current knowledge on intratumoral therapies, a novel modality with increased utility in cancer treatment, and T-VEC, the only U.S. FDA-approved oncolytic viral therapy, for medical oncologists. This review evaluates approaches to incorporate T-VEC into daily practice to offer the possibility of response in selected melanoma patients with manageable adverse events as compared with other available immunotherapies.

Hamid O ，Ismail R ，Puzanov I 《-》

The Role of Oncolytic Viruses in the Treatment of Melanoma.

Bayan CY ，Lopez AT ，Gartrell RD ，Komatsubara KM ，Bogardus M ，Rao N ，Chen C ，Hart TD ，Enzler T ，Rizk EM ，Pradhan JS ，Marks DK ，Geskin LJ ，Saenger YM ... -  《-》

Oncolytic virus therapy: A new era of cancer treatment at dawn.

Oncolytic virus therapy is perhaps the next major breakthrough in cancer treatment following the success in immunotherapy using immune checkpoint inhibitors. Oncolytic viruses are defined as genetically engineered or naturally occurring viruses that selectively replicate in and kill cancer cells without harming the normal tissues. T-Vec (talimogene laherparepvec), a second-generation oncolytic herpes simplex virus type 1 (HSV-1) armed with GM-CSF, was recently approved as the first oncolytic virus drug in the USA and Europe. The phase III trial proved that local intralesional injections with T-Vec in advanced malignant melanoma patients can not only suppress the growth of injected tumors but also act systemically and prolong overall survival. Other oncolytic viruses that are closing in on drug approval in North America and Europe include vaccinia virus JX-594 (pexastimogene devacirepvec) for hepatocellular carcinoma, GM-CSF-expressing adenovirus CG0070 for bladder cancer, and Reolysin (pelareorep), a wild-type variant of reovirus, for head and neck cancer. In Japan, a phase II clinical trial of G47∆, a third-generation oncolytic HSV-1, is ongoing in glioblastoma patients. G47∆ was recently designated as a "Sakigake" breakthrough therapy drug in Japan. This new system by the Japanese government should provide G47∆ with priority reviews and a fast-track drug approval by the regulatory authorities. Whereas numerous oncolytic viruses have been subjected to clinical trials, the common feature that is expected to play a major role in prolonging the survival of cancer patients is an induction of specific antitumor immunity in the course of tumor-specific viral replication. It appears that it will not be long before oncolytic virus therapy becomes a standard therapeutic option for all cancer patients.

Fukuhara H ，Ino Y ，Todo T 《-》