Virotherapy Products

Virotherapy represents the experimental use of oncolytic viruses to treat cancer. This type of treatment provides a plethora of potential advantages in comparison to conventional cancer therapies, such as selectiveness for tumor cells, initiation of a potent antitumor response, and cytotoxicity for surviving cancer and stromal cells.

The intratumoral injection was one way to administer oncolytic viruses in a majority of clinical trials that have been performed thus far. Comparatively, regional or intravenous delivery was examined in just a fraction of studies. Albeit overall efficacy against tumors has been limited, clinical experience has shown a favorable safety and toxicity profile, as well as a number of tumor responses.

Update on oncolytic viruses for cancer treatment

Products used in virotherapy

A nonpathogenic, oncolytic ECHO-7 virus adapted for melanoma that has not been genetically modified was the first approved virotherapy product. Registered in Latvia in 2004 under the name Rigvir, this virus represents a specific immunotherapy approach for patients with melanoma, and can result in 4.39-6.57-fold lower mortality when compared to a group under observation only.

Talimogene laherparepvec, formerly known as OncoVEX, is a modified injectable oncolytic herpes simplex virus that codes for granulocyte/macrophage colony-stimulating factor (GM-CSF). Akin to Rigvir, it is also used in the treatment of advanced melanoma and exerts its antitumor activity by augmenting immune responses and directly mediating cell death.

In phase I and II clinical trials, the intratumoral administration of talimogene laherparepvec twice a week to patients with various solid tumors was well tolerated. On March 19, 2013, Amgen announced encouraging results of a Phase III clinical trial in melanoma patients. A significant difference was observed in the durable response rate between the talimogene laherparepvec and the control group.

Virotherapy was also used for pancreatic cancer. ONXY-015 (dl1520) represents the first replication-competent oncolytic adenovirus that was used in clinical trials for that purpose, which has been engineered to lack expression of the E1B 55 kDa protein, as this protein is needed to block apoptosis in infected cells. Other adenoviruses lacking the E1B 19 kDa protein were also candidates for pancreatic cancer therapy.

Current and future challenges

Oncolytic virotherapy is not yet a mature field, and incidents were noted where people died or became seriously ill due to this type of treatment. To make this therapy safe and successful, production rates of viral particles in the infected cancer cells must outstrip the growth rate of the uninfected cancer cells.

There are many benefits to oncolytic virotherapy if researchers can overcome certain drawbacks. The selective nature of virotherapy ensures that healthy tissues are minimally affected. A considerable amount of active research is currently being done to improve the accessibility, efficacy, and overall safety of oncolytic virotherapy.


Further Reading

Last Updated: Feb 16, 2023

Dr. Tomislav Meštrović

Written by

Dr. Tomislav Meštrović

Dr. Tomislav Meštrović is a medical doctor (MD) with a Ph.D. in biomedical and health sciences, specialist in the field of clinical microbiology, and an Assistant Professor at Croatia's youngest university - University North. In addition to his interest in clinical, research and lecturing activities, his immense passion for medical writing and scientific communication goes back to his student days. He enjoys contributing back to the community. In his spare time, Tomislav is a movie buff and an avid traveler.


Please use one of the following formats to cite this article in your essay, paper or report:

  • APA

    Meštrović, Tomislav. (2023, February 16). Virotherapy Products. News-Medical. Retrieved on September 29, 2023 from

  • MLA

    Meštrović, Tomislav. "Virotherapy Products". News-Medical. 29 September 2023. <>.

  • Chicago

    Meštrović, Tomislav. "Virotherapy Products". News-Medical. (accessed September 29, 2023).

  • Harvard

    Meštrović, Tomislav. 2023. Virotherapy Products. News-Medical, viewed 29 September 2023,


The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.