Oncolytic virotherapy: Challenges and solutions.

Viruses as cancer therapies have attracted attention since the 19th century. Scientists observation that viruses can preferentially lyse cancer cells rather than healthy cells, created the field of oncolytic virology. Like other therapeutic strategies, oncolytic virotherapy has challenges, such as penetration into tumor bulk, anti-viral immune responses, off-target infection, adverse conditions in the tumor microenvironment, and the lack of specific predictive and therapeutic biomarkers. Whilst much progress has been made, as highlighted by the first Food and Drug Administration approval of an oncolytic virus talimogene laherparepvec (T-VEC) in 2015, addressing these issues remains a significant hurdle. Here we discuss different types of oncolytic viruses, their application in clinical trials, and finally challenges faced by the field of oncolytic virotherapy and strategies to overcome them.

Goradel NH ，Baker AT ，Arashkia A ，Ebrahimi N ，Ghorghanlu S ，Negahdari B ... -  《-》

Oncolytic virotherapy as promising immunotherapy against cancer: mechanisms of resistance to oncolytic viruses.

Goradel NH ，Alizadeh A ，Hosseinzadeh S ，Taghipour M ，Ghesmati Z ，Arashkia A ，Negahdari B ... -  《-》

Talimogene laherparepvec (T-VEC) as cancer immunotherapy.

Talimogene laherparepvec (T-VEC) is the first-in-class oncolytic virus immunotherapy for the treatment of cancer and was generated from an attenuated, recombinant herpes simplex virus. T-VEC has demonstrated therapeutic activity in melanoma patients and is being tested in a number of other cancers alone and in combination with standard cancer therapeutics and other immunotherapy agents. This review will discuss the current landscape of melanoma, the construction and application of T-VEC for melanoma along with other indications for T-VEC, as well as highlight some of the novel challenges with oncolytic virus immunotherapy as it enters into clinical practice.

Kohlhapp FJ ，Zloza A ，Kaufman HL 《DRUGS OF TODAY》

Oncolytic Virotherapy by HSV.

Watanabe D ，Goshima F 《-》

Molecular Pathways: Mechanism of Action for Talimogene Laherparepvec, a New Oncolytic Virus Immunotherapy.

Oncolytic viruses are native or engineered viruses that preferentially replicate in and lyse cancer cells. Selective tumor cell replication is thought to depend on infection of neoplastic cells, which harbor low levels of protein kinase R (PKR) and dysfunctional type I IFN signaling elements. These changes allow more efficient viral replication, and with selected deletion of specific viral genes, replication in normal cells with activated PKR may not be possible. Direct tumor cell lysis, release of soluble tumor antigens, and danger-associated molecular factors are all thought to help prime and promote tumor-specific immunity. Talimogene laherparepvec (T-VEC) is a genetically modified herpes simplex virus, type I and is the first oncolytic virus to demonstrate a clinical benefit in patients with melanoma. T-VEC has also been evaluated for the treatment of head and neck cancer, pancreatic cancer, and likely other types of cancer will be targeted in the near future. T-VEC has been modified for improved safety, tumor-selective replication, and induction of host immunity by deletion of several viral genes and expression of human granulocyte-macrophage colony stimulating factor. Although the mechanism of action for T-VEC is incompletely understood, the safety profile of T-VEC and ability to promote immune responses suggest future combination studies with other immunotherapy approaches including checkpoint blockade through PD-1, PD-L1, and CTLA-4 to be a high priority for clinical development. Oncolytic viruses also represent unique regulatory and biosafety challenges but offer a potential new class of agents for the treatment of cancer.

Kohlhapp FJ ，Kaufman HL 《-》