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An oncolytic virus is a virus that preferentially infects and kills cancer cells. As the infected cancer cells are destroyed by lysis, they release new infectious virus particles to help destroy the remaining tumour. Oncolytic viruses are thought not only to cause direct destruction of the tumour cells, but also to stimulate host anti-tumour immune responses. The potential of viruses as anti-cancer agents was first realised in the early twentieth century, although coordinated research efforts did not begin until the 1960s. A number of viruses including adenovirus, reovirus, measles, herpes simplex, Newcastle disease virus and vaccinia have now been clinically tested as oncolytic agents. Most current oncolytic viruses are engineered for tumour selectivity, although there are naturally occurring examples such as reovirus and the SVV-001 Seneca Valley virus, resulting in clinical trials. As of 2011, only limited human trials had been performed. Nevertheless, the drug talimogene laherparepvec (OncoVex, T-VEC) recently (Jan 2012) reported the first positive interim Phase III clinical trial results for an oncolytic virus, making it likely that it will also be the first one approved for use (for the treatment of advanced melanoma). However, skeptics have questioned the clinical relevance of this interim data citing that the awaited overall survival data will be the final judgement and that it is likely that patient benefit will be maximised in combination with other therapies, which this trial did not test.〔(【引用サイトリンク】title=Amgen, Form 8-K, Current Report, Filing Date Jan 26, 2012 )〕 2015 update: In a combined decision, members of the FDA’s Oncologic Drugs Advisory Committee (ODAC) and Cellular, Tissue and Gene Therapies Advisory Committee (CTGTAC) voted 22-1 to recommend approval of the oncolytic immunotherapy talimogene laherparepvec (T-VEC) as a treatment for patients with advanced melanoma. A final approval decision from the FDA is scheduled by October 27, 2015. Approved in Latvia oncolytic virus RIGVIR was registered in Georgia in February 2015. Melanoma Research published new data on RIGVIR efficacy, showing that early stage melanoma patients treated with oncolytic virus RIGVIR had 4.39–6.57-fold lower mortality than those, who according to melanoma treatment guidelines did not receive virotherapy and were only observed. ==History== A connection between cancer regression and viruses has long been theorized, and case reports of regression (cervical cancer, Burkitt lymphoma, Hodgkin lymphoma) after immunization or infection with an unrelated virus appeared at the beginning of the 20th century. Efforts to treat cancer through immunization or deliberate infection with a virus began in the mid-20th century.〔 As the technology for creating a custom virus did not exist, all early efforts focused on finding natural oncolytic viruses. During the 1960s, promising research involved using poliovirus, adenovirus,〔 Coxsackie virus, ECHO enterovirus RIGVIR〔Chumakov P, Morozova V, Babkin I, Baikov I, Netesov S, Tikunova N. Oncolytic enteroviruses. Molecular Biology, 2012, Vol. 46, No. 5, pp. 639-650. ISSN 0026-8933. URL:http://www.virotherapy.eu/publications/preclinical/oncolytic-enteroviruses-2012.pdf〕 and others.〔 The early complications were occasional cases of uncontrolled infection, resulting in significant morbidity and mortality; the very frequent development of an immune response, while harmless to the patient,〔 destroyed the virus and thus prevented it from destroying the cancer.〔 Only certain cancers could be treated through virotherapy was also recognized very early.〔 Even when a response was seen, these responses were neither complete nor durable.〔 The field of virotherapy was nearly abandoned for a time, as the technology required to modify viruses didn't exist and chemotherapy and radiotherapy technology enjoyed early success. However, now these technologies have been thoroughly developed, cancer is still a major cause of mortality and there is still a need for novel cancer therapies, hence the return to this sidelined therapy now using the recently developed genetic technology required to engineer viruses.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Oncolytic virus」の詳細全文を読む スポンサード リンク
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