Oncolytic Virus Therapy Innovation: Delytact Treating Glioma

Posted by beauty33 on September 24th, 2021

In June 2021, the oncolytic virus therapy Delytact (teserpaturev/G47?) developed by Daiichi Sankyo has received conditional and time-limited approval for the treatment of malignant glioma from the Ministry of Health, Labour and Welfare (MHLW) of Japan. This is the world\'s first oncolytic virus therapy approved for the treatment of primary brain tumors and the fourth oncolytic virus product in the world.

Delytact Treating Glioma

Glioblastoma is a primary brain tumor that results from the canceration of glial cells in the brain tissue, accounting for 80% of all primary brain tumors. Glioblastoma has the characteristics of high malignancy, rapid disease progression, high recurrence probability, and limited follow-up treatments.

Delytact is a third-generation oncolytic virus developed based on the herpes simplex virus (HSV-1). Through genetic engineering modification of the HSV genome, the selective replication of Delytact in tumor cells is enhanced, and while lysing tumor cells, it stimulates the human body\'s anti-tumor immune response, thereby enhancing the anti-tumor activity while maintaining a high safety level.

In the phase II clinical trial, 12 of the 13 patients survived more than one year after treatment, and the one-year survival rate was 92.3%. In contrast, the one-year survival rate for standard treatment of postoperative radiotherapy and chemotherapy is only 15%. According to the results of the phase II study, Delytact currently only obtains conditional and time-limited approval in Japan. The subsequent approval of this indication may depend on the verification of the clinical benefits and safety of comparative clinical efficacy studies after marketing. Delytact is not allowed to be used outside of Japan.

Development of Oncolytic Virus Therapy

It was discovered a long time ago that some cancer patients\' tumors shrink or disappear after being infected with the virus. A special case was also found during the epidemic of COVID-19 that after a patient with advanced Hodgkin\'s lymphoma was infected with the virus, most of the tumor in his body disappeared. These cases have shown that the human immune response triggered by the virus infection may have anti-cancer effects.

In the 1950s and 1980s, researchers began clinical trials to test the anticancer efficacy of wild-type or attenuated viruses. However, the challenge is that there is no effective means to control their toxicity and allow them to replicate only in cancer cells.

In 1991, researchers from Harvard Medical School published a study in the journal Science, which showed that by genetically engineering HSV-1 viruses, they can make them selectively replicate in glioma cells and be used in animal models, which showed a gratifying curative effect. This research has opened up a new era in the development of oncolytic viruses through the design and construction of viral genomes.

The current oncolytic virus therapy can not only activate immune cells, but also change the tumor microenvironment and improve the therapeutic effect. Compared with other tumor treatment methods, oncolytic virus therapy has the advantages of high replication efficiency, good killing effect, and less toxic side effects.

“The property of oncolytic viruses to stimulate anti-tumor immune responses means that oncolytic virus combination therapies with other immunotherapies, including checkpoint inhibitors, they are expected to further improve their anti-cancer efficacy,” introduced by a scientist from Creative Biolabs, a biotech company focusing on oncolytic virus therapy development services, “moreover, the modification of oncolytic viruses can give them transgenes expressing other proteins, thereby further enhancing anti-cancer activity. In the future, oncolytic viruses are expected to become a new treatment model for cancer treatment.”

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