# Siddharth Balachandran
**Siddharth Balachandran** is a virologist and cancer researcher who studies inflammatory cell death and virus–host interactions. He is Professor and Director of the Center for Immunology at [Fox Chase Cancer Center](https://www.edgepedia.org/fox-chase-cancer-center) in Philadelphia, where his laboratory dissects the molecular mechanisms of RIPK3-kinase-driven cell death activated by microbes, viruses, cytokines, and cellular stresses.[1](https://www.foxchase.org/siddharth-balachandran) He is known for showing that influenza viruses trigger the Z-nucleic acid sensor ZBP1 to induce necroptosis, and for developing a RIPK3 inhibitor that prevents lung injury in severe influenza.[2](https://pmc.ncbi.nlm.nih.gov/articles/PMC7153753/) • [3](https://www.foxchase.org/index%2ephp/news/2024-04-10-fox-chase-cancer-center-study-demonstrates-promise-of-new-therapy-for-lung-injury-from-severe-flu-infection)
| Key facts | |
|---|---|
| Field | Molecular biology of virus–host interactions and inflammatory cell death[1](https://www.foxchase.org/siddharth-balachandran) |
| Current role | Professor and Director of the Center for Immunology, Fox Chase Cancer Center (as of February 2026)[4](https://www.sbms.hku.hk/events/viruses-and-cell-death-mechanisms-therapeutic-implications) |
| Training | BS Chemistry, Angelo State University, 1995; PhD Immunology & Molecular Pathogenesis, Emory University, 2001; postdoc with Glen Barber, University of Miami[1](https://www.foxchase.org/siddharth-balachandran) • [4](https://www.sbms.hku.hk/events/viruses-and-cell-death-mechanisms-therapeutic-implications) |
| Signature work | "Influenza Virus Z-RNAs Induce ZBP1-Mediated Necroptosis", *Cell*, 2020[2](https://pmc.ncbi.nlm.nih.gov/articles/PMC7153753/) |
| Therapy result | RIPK3 inhibitor UH15-38 blocked necroptosis and dampened lung inflammation in flu-infected mice even when given late in infection (*Nature*, April 2024)[3](https://www.foxchase.org/index%2ephp/news/2024-04-10-fox-chase-cancer-center-study-demonstrates-promise-of-new-therapy-for-lung-injury-from-severe-flu-infection) |
| Funding | National Institute of Allergy and Infectious Diseases, National Institute of Neurological Disorders and Stroke, and National Cancer Institute, including R01AI135025, and R01CA269975[1](https://www.foxchase.org/siddharth-balachandran) |
| Industry | Co-founder of Vaayu Therapeutics; Scientific Advisory Board of Ascend Biopharmaceuticals; multiple patents in viral, inflammatory, and malignant disease[4](https://www.sbms.hku.hk/events/viruses-and-cell-death-mechanisms-therapeutic-implications) |
## Education and career
Balachandran earned a BS in Chemistry from [Angelo State University](https://www.edgepedia.org/angelo-state-university) in [San Angelo, Texas](https://www.edgepedia.org/san-angelo-texas), in 1995, and a PhD in [Immunology](https://www.edgepedia.org/immunology) & Molecular Pathogenesis from Emory University in 2001.[1](https://www.foxchase.org/siddharth-balachandran) His dissertation, *Roles for the double-stranded RNA-dependent protein kinase PKR in apoptosis and innate immunity to viral infection*, showed that PKR-deficient mice were extremely susceptible to vesicular stomatitis virus (VSV) and influenza virus, and that PKR inhibits VSV replication at the level of viral mRNA translation by phosphorylating eIF2α; according to the dissertation record, the work was titled *Roles for the double-stranded RNA-dependent protein kinase PKR in apoptosis and innate immunity to viral infection*.[5](https://www.globethesis.com/?t=1464390011498020)
He carried out postdoctoral research with [Glen Barber](https://www.edgepedia.org/glen-barber) at the [University of Miami](https://www.edgepedia.org/university-of-miami), then joined Fox Chase Cancer Center as a tenure-track Assistant Professor. He was promoted to Associate Professor with tenure in 2014 and to Full Professor in 2018, and holds adjunct professorships at Temple and Drexel Universities.[4](https://www.sbms.hku.hk/events/viruses-and-cell-death-mechanisms-therapeutic-implications) At Fox Chase he is also a member of the Cancer Signaling and Microenvironment research program.[1](https://www.foxchase.org/siddharth-balachandran)
## Representative work
According to the paper itself, his 2020 *Cell* paper, Influenza Virus Z-RNAs Induce ZBP1-Mediated Necroptosis, published 19 March 2020 with Balachandran as corresponding author, showed that replicating influenza A virus generates Z-RNAs that activate ZBP1 in the nucleus of infected cells, initiating RIPK3-mediated MLKL activation, nuclear envelope disruption, leakage of DNA into the cytosol, and eventual necroptosis.[2](https://pmc.ncbi.nlm.nih.gov/articles/PMC7153753/) In the same model, about 30% of Mlkl−/− mice survived a lethal influenza dose and fully recovered by 3 weeks, while all Zbp1−/− and Ripk3−/− mice died within about 2 weeks.[2](https://pmc.ncbi.nlm.nih.gov/articles/PMC7153753/)
## Research program: ZBP1, Z-RNAs, and necroptosis
Necroptosis is a regulated, lytic form of cell death driven by the RIPK3 kinase and its substrate MLKL. Balachandran's lab found that influenza A viruses produce Z-RNAs that trigger the sensor ZBP1, activating RIPK3 and driving both MLKL-dependent necroptosis and a parallel FADD/caspase 8-mediated apoptosis pathway.[1](https://www.foxchase.org/siddharth-balachandran) The 2020 *Cell* paper reported that the primary source of ZBP1-activating ligands appeared to be Z-RNAs derived from defective viral genomes rather than full-length genomes, and proposed RIPK3 kinase inhibitors as a therapeutic entry point in severe influenza.[2](https://pmc.ncbi.nlm.nih.gov/articles/PMC7153753/)
The lab has also identified interferon-driven activation of RIPK1/3 kinases and two mechanisms, the adaptor protein FADD and the transcription factor NF-κB, that protect unstimulated cells from interferon-triggered necroptosis.[1](https://www.foxchase.org/siddharth-balachandran) A 2025 *Nature* paper (volume 648, pages 707–716) revised the ligand question: host cell-encoded Z-RNAs, not viral Z-RNAs, are major and sufficient ZBP1-activating ligands after HSV-1 and influenza infection. These cellular Z-RNAs map to intergenic endogenous retroelements within abnormally long 3′ extensions of host mRNAs arising from virus-driven disruption of transcription termination (DoTT), which disables CPSF-mediated 3′ processing. Mutant viruses lacking ICP27 or NS1, the proteins that trigger DoTT, did not induce host Z-RNA accrual and were attenuated in stimulating ZBP1; DoTT activates within about 2 hours of infection.[6](https://www.nature.com/articles/s41586-025-09705-5) On the cancer side, the lab is developing small-molecule approaches to activate ZBP1 and trigger on-demand nuclear necroptosis in tumor cells, currently evaluated in mouse models of melanoma and other solid cancers.[1](https://www.foxchase.org/siddharth-balachandran)
## Funding, translation, and industry
His lab is funded by the [National Institute of Allergy and Infectious Diseases](https://www.edgepedia.org/national-institute-of-allergy-and-infectious-diseases), the National Institute of Neurological Disorders and Stroke, and the [National Cancer Institute](https://www.edgepedia.org/national-cancer-institute), including grants R01AI135025 and R01CA269975.[1](https://www.foxchase.org/siddharth-balachandran) The 2024 *Nature* study reported that the RIPK3 inhibitor UH15-38 selectively blocked necroptosis and dampened inflammation in flu-infected mice even when administered late in infection; UH15-38 stopped necroptosis without interfering with the apoptosis pathway, something previous RIPK3 inhibitors could not do.[3](https://www.foxchase.org/index%2ephp/news/2024-04-10-fox-chase-cancer-center-study-demonstrates-promise-of-new-therapy-for-lung-injury-from-severe-flu-infection) • [7](https://cen.acs.org/pharmaceuticals/drug-discovery/Compound-prevents-flu-related-lung-damage-in-mice/102/web/2024/04) Balachandran reports that UH15-38 works well against mouse RIPK3 but is less effective against the human version, and he co-founded Vaayu Therapeutics to develop next-generation analogs for human use.[7](https://cen.acs.org/pharmaceuticals/drug-discovery/Compound-prevents-flu-related-lung-damage-in-mice/102/web/2024/04) He holds multiple patents in therapeutic interventions for viral, inflammatory, and malignant disease, and joined the Scientific Advisory Board of Ascend Biopharmaceuticals.[4](https://www.sbms.hku.hk/events/viruses-and-cell-death-mechanisms-therapeutic-implications) Following his 2022 *Nature* study on ADAR1 masking ZBP1-driven necroptosis, Fox Chase is conducting a phase 1 trial of the compound CBL0137 alongside immunotherapy in melanoma patients; Balachandran notes that immunotherapy is currently ineffective for 70% to 80% of cancer patients, and that any disease involving chronic inflammation and necrotic death, such as colitis, lung fibrosis, liver disease, or psoriasis, could potentially benefit from RIPK3-pathway blockade.[3](https://www.foxchase.org/index%2ephp/news/2024-04-10-fox-chase-cancer-center-study-demonstrates-promise-of-new-therapy-for-lung-injury-from-severe-flu-infection)
## Recent developments
Three developments mark the period. First, the April 2024 *Nature* paper moved necroptosis blockade from hypothesis to a demonstrated therapy in mice, with a selective RIPK3 inhibitor effective even late in infection.[3](https://www.foxchase.org/index%2ephp/news/2024-04-10-fox-chase-cancer-center-study-demonstrates-promise-of-new-therapy-for-lung-injury-from-severe-flu-infection) Second, the October 2025 *Nature* paper relocated the ZBP1 ligand from viral defective genomes to host Z-RNAs generated by DoTT, a host surveillance mechanism acting within about 2 hours of infection.[6](https://www.nature.com/articles/s41586-025-09705-5) Third, 2025 outputs include "RIPK1 is required for ZBP1-driven necroptosis in human cells" in *PLoS Biology* (21 February 2025) and a review, "ZBP1-driven cell death in severe influenza", in *Trends in Microbiology* (January 2025).[1](https://www.foxchase.org/siddharth-balachandran) As of February 2026 he remains Professor and Director of the Center for Immunology at Fox Chase.[4](https://www.sbms.hku.hk/events/viruses-and-cell-death-mechanisms-therapeutic-implications)
## References
1. [Siddharth Balachandran | Fox Chase Cancer Center](https://www.foxchase.org/siddharth-balachandran)
2. [Influenza Virus Z-RNAs Induce ZBP1-Mediated Necroptosis (Cell, 2020)](https://pmc.ncbi.nlm.nih.gov/articles/PMC7153753/)
3. [Fox Chase Cancer Center Study Demonstrates Promise of New Therapy for Lung Injury From Severe Flu Infection](https://www.foxchase.org/index%2ephp/news/2024-04-10-fox-chase-cancer-center-study-demonstrates-promise-of-new-therapy-for-lung-injury-from-severe-flu-infection)
4. [Viruses and Cell Death: Mechanisms & Therapeutic Implications | HKU SBMS seminar biography](https://www.sbms.hku.hk/events/viruses-and-cell-death-mechanisms-therapeutic-implications)
5. [Roles for the double-stranded RNA-dependent protein kinase PKR in apoptosis and innate immunity to viral infection (PhD dissertation record)](https://www.globethesis.com/?t=1464390011498020)
6. [Host cell Z-RNAs activate ZBP1 during virus infections (Nature, 2025)](https://www.nature.com/articles/s41586-025-09705-5)
7. [Compound prevents flu-related lung damage in mice (C&EN, 2024)](https://cen.acs.org/pharmaceuticals/drug-discovery/Compound-prevents-flu-related-lung-damage-in-mice/102/web/2024/04)
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*Topic: Encyclopedia › Life and health › Life and health scientists › Life scientists › Researchers in immunology, microbiology, and virology › Virology › Viral pathogenesis and immunity researchers*
*Initially written Sep 21, 2026 · Reviewed: Sep 25, 2026 · Edited: Sep 25, 2026; Oct 11, 2026; Oct 15, 2026 · Last review: Sep 25, 2026*
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