# Hietanen 2022: the marketed oncolytic virus Rigvir was no more oncolytic than any other echovirus isolate

Source: https://onco.cc/key-papers/paper-hietanen-rigvir-echovirus-viruses-2022/  
OnCo record `paper-hietanen-rigvir-echovirus-viruses-2022` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A virus sold for years as a cancer treatment in Latvia was sequenced and tested against ordinary strains of the same virus, and it killed cancer cells no better, and infected healthy cells too.

## Summary

Rigvir was a cell-adapted enterovirus derived from an echovirus 7 isolate, registered in Latvia and promoted internationally as an oncolytic virotherapy, particularly for melanoma. Hietanen and colleagues sequenced Rigvir and five other echovirus 7 isolates, analysed the genomes, and ran cell infectivity assays on eight cell lines including both cancer and non-cancer lines.

Phylogenetically Rigvir sat in its own clade at the root, most distant from the other isolates, and carried nine unique capsid mutations, six of them at surface-exposed residues, one at the contact interface with decay-accelerating factor. Functionally, the infectivity assays showed no discernible difference in oncolytic effect between Rigvir, the Wallace prototype and four other echovirus 7 isolates, and Rigvir also infected non-cancer cell lines. The authors conclude that the claim of Rigvir being an effective treatment against multiple cancers is not warranted by the evidence presented, and that neither the bioinformatics nor the cell work reveals a mechanism.

## Fields

- Kind: Key paper
- Last checked: 2026-09-25
- Journal: Viruses
- Year: 2022
- DOI: 10.3390/v14030525
- Authors: Hietanen E, Koivu MKA, Susi P
- Findings: Rigvir showed no discernible difference in oncolytic effect from the Wallace prototype or four other echovirus 7 isolates across eight cell lines.; Rigvir infected non-cancer cell lines as well as cancer lines, contradicting the claim that it is oncotropic.; Phylogenetic analysis placed Rigvir in its own clade at the root of the tree, most distant from the other echovirus 7 isolates studied.; Nine unique capsid mutations were found, six at surface-exposed residues, one at the contact interface with decay-accelerating factor.; No mechanism for the claimed oncolytic and oncotropic behaviour emerged from either the sequence analysis or the infectivity work.
- What it means: Rigvir is the field's clearest case of a product sold far ahead of its evidence: a national registration, international marketing to patients, and no randomised trial. This is the laboratory work that should have been done first. It is here because a field that produces striking single cases attracts exactly this, and readers deserve to know that an approval somewhere in the world is not the same as evidence.
- Caveats: Cell culture work, which cannot by itself disprove a clinical effect; the point is that no adequate clinical evidence exists either.; The manufacturer disputed the findings in a published comment, to which the authors replied; both exchanges are in the same journal.; Rigvir is not a genetically engineered oncolytic virus and does not represent the mainstream of the field.

## Sources

- Viruses 2022: https://doi.org/10.3390/v14030525
- PubMed: https://pubmed.ncbi.nlm.nih.gov/35336934/
- Authors' reply to the manufacturer's comment: https://doi.org/10.3390/v14092078

## Connected records

- cancers: [Melanoma](https://onco.cc/cancers/melanoma/)
- fronts: [Immunotherapy](https://onco.cc/fronts/immunotherapy/)
- technologies: [Oncolytic viruses](https://onco.cc/technologies/oncolytic-virus/)

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