# Oncolytic viruses that make interleukin-12 only inside the tumour

Source: https://onco.cc/ideas/idea-bio2-oncolytic-regulated-il12/  
OnCo record `idea-bio2-oncolytic-regulated-il12` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Interleukin-12 is an immune-stimulating cytokine that caused severe toxicity when injected into the bloodstream in the 1990s and was abandoned. An oncolytic herpes or adenovirus carrying the interleukin-12 gene under a drug-inducible promoter makes it only inside the tumour, keeping exposure local; trials include recurrent glioblastoma.

## Summary

Systemic interleukin-12 caused severe toxicity in the 1990s and was abandoned. Oncolytic herpes and adenovirus vectors carrying interleukin-12 under regulated or drug-inducible promoters, including trials in recurrent glioblastoma, keep exposure local and measurable. Combining a regulated cytokine payload with checkpoint blockade is a rational path to converting cold tumours.

## Fields

- Kind: Idea
- Last checked: 2026-09-08
- Hypothesis: A regulated intratumoural interleukin-12 payload achieves tumour-to-plasma cytokine ratios above 100 and produces T-cell infiltration in previously cold lesions, without dose-limiting systemic toxicity.
- Rationale: The failure of interleukin-12 was pharmacokinetic, not immunological, and local delivery is exactly the right fix. Oncolytic products are already approved in melanoma and bladder cancer, so the manufacturing and regulatory route exists.
- Proposed test: Dose-escalation with paired biopsies and matched plasma cytokine measurement, reporting tumour-to-plasma ratio and change in CD8 density as the primary endpoints, before efficacy expansion.
- Maturity: early-clinical
- Actor: industry

## Sources

- Bottleneck evidence (Cold tumours and the immunosuppressive microenvironment): Haslam & Prasad, Estimation of the percentage of US patients eligible for and responding to checkpoint inhibitors (JAMA Netw Open 2019): https://doi.org/10.1001/jamanetworkopen.2019.2535

## Connected records

- cancers: [Bladder & urothelial cancer](https://onco.cc/cancers/urothelial/), [Glioma & glioblastoma](https://onco.cc/cancers/glioblastoma/), [Melanoma](https://onco.cc/cancers/melanoma/)
- technologies: [Cytokines & engineered cytokines](https://onco.cc/technologies/cytokine-therapy/), [Immune checkpoint inhibitors](https://onco.cc/technologies/checkpoint-inhibitor/), [Oncolytic viruses](https://onco.cc/technologies/oncolytic-virus/)
- drugs: [Cretostimogene grenadenorepvec](https://onco.cc/drugs/cretostimogene/), [Nadofaragene firadenovec](https://onco.cc/drugs/nadofaragene-firadenovec/), [Talimogene laherparepvec](https://onco.cc/drugs/talimogene-laherparepvec/), [Vusolimogene oderparepvec](https://onco.cc/drugs/vusolimogene-oderparepvec/)
- companies: [CG Oncology](https://onco.cc/companies/cg-oncology/), [Replimune](https://onco.cc/companies/replimune/)
- people: [Kevin Harrington](https://onco.cc/people/kevin-harrington/)
- bottlenecks: [Cold tumours and the immunosuppressive microenvironment](https://onco.cc/bottlenecks/b-tme-immunosuppression/), [The brain: barrier and sanctuary](https://onco.cc/bottlenecks/b-brain-delivery/)
- key papers: [Estimation of the Percentage of US Patients With Cancer Who Are Eligible for and Respond to Checkpoint Inhibitor Immunotherapy Drugs](https://onco.cc/key-papers/paper-haslam-jama-netw-open/)

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