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HSV-tk gene therapy (HSVtk / Zalmoxis / TK therapy)

✓ Approved

Megapharm Ltd · POLA1 · Cell-based Therapies

What is HSV-tk gene therapy?

HSV-tk gene therapy is a cell-based therapies developed by Megapharm Ltd. It is approved for therapeutic indications via injectable (others) or intravenous (iv).

Drug Profile

Brand NamesHSVtk, Zalmoxis, TK therapy
CompanyMegapharm Ltd
Drug ClassCell-based Therapies, Gene Therapy
Molecular TargetPOLA1
RouteInjectable (Others), Intravenous (IV)
StatusApproved
Sources: ClinicalTrials.gov, Megapharm Ltd

Mechanism of Action

Molecular Targets

HSV-tk gene therapy acts on 1 molecular target:

POLA1DNA polymerase alpha 1, catalytic subunit (PDR, POLA)
Want deeper analysis?Noah AI can explain complex mechanisms and compare to similar drugs.

Therapeutic Indications

HSV-tk gene therapy is developed for 1 unique indication across 1 therapeutic area.

Therapeutic AreaConditionPhase
Immune system disordersChronic graft versus host disease✓ Approved

Related Research Articles

PubMedbioRxiv : the preprint server for biology2026-07-17

HSV-1 hijacks the DNA repair protein RAD51 at gene promoters to drive viral transcription.

Kumar Namrata N, Dunn Laura E M LEM, Tessier Tanner M TM, Hayer Katharina E KE et al.

Productive infection by Herpes Simplex Virus type 1 (HSV-1) requires initiation of efficient viral gene expression. Upon nuclear entry, HSV-1 genomes are associated with several cellular factors, including DNA repair proteins. It is unclear how these cellular factors impact viral processes at early stages of infection. In this study, we investigate the role of RAD51, a core homologous recombination (HR) factor. We measured nascent viral transcription and show that RAD51 plays a pro-viral role in infection by promoting immediate-early viral gene expression. We demonstrate that RAD51 binds GC-rich gene promoter of ICP4 and directly promotes gene expression. We also reveal a previously unknown interaction between RAD51 and ADNP, a subunit of the ChAHP complex, known for its role in transcription regulation. We propose a model where RAD51 binds incoming genomes at promoter regions regulating the genome landscape and allowing for efficient transcription initiation.

PMID 42465427
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PubMedThe ocular surface2026-07-17

Lipocalin 2 as a novel target of pralatrexate mitigating corneal epithelial damage in a mouse model of herpes simplex keratitis.

Wu Jing J, Lyu Ruining R, Chen Li L, Wu Lanjingya L et al.

Herpes simplex keratitis (HSK), a sight-threatening ocular infection caused by herpes simplex virus (HSV), primarily induces blindness through corneal damage driven by the lytic death of infected epithelial cells. Only a limited number of antiviral agents are approved for HSK management, highlighting an urgent need to explore novel anti-HSK agents. At present, the antifolate agent pralatrexate (PDX), originally developed as an anti-tumor agent, demonstrates robust anti-HSV-1 activity both in vitro and in vivo, including ACV-resistant strain HSV-1/153. Moreover, PDX treatment also alleviates HSV-1-induced corneal epithelial damage and inflammation progression. We identified a previously unexplored novel mode of action for PDX against HSV-1. Mechanistically, PDX suppresses lipocalin-2 (LCN2) expression by reducing P65 phosphorylation and inhibiting its nuclear translocation, which may be involved in HSV-1 replication inhibition and corneal inflammation progression reduction. In conclusion, our work highlights PDX as a promising anti-HSK agent, given its efficacy against viral replication and corneal epithelial damage via inhibiting LCN2 expression.

PMID 42462968
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PubMedSpectrochimica acta. Part A, Molecular and biomolecular spectroscopy2026-07-17

Rapid assessment of soil nutrients under continuous Gastrodia elata cropping using near- and mid-infrared spectroscopy combined with multi-strategy machine learning.

Zhang Wentao W, Xie Baiheng B, Ma Jinfang J, Zhang Xiangyu X et al.

To enable rapid and non-destructive quantitative assessment of soil nutrients in Gastrodia elata continuous-cropping fields, soils with different cultivation histories were collected from a G. elata experimental site in Bijie, Guizhou, China, including never planted (WZZ), continuous cropping for one year (LZ1), continuous cropping for two years (LZ2), and G. elata-konjac rotation (TMLuZ). Reference concentrations of soil organic matter (SOM), total nitrogen (TN), alkali-hydrolyzable nitrogen (HN), total phosphorus (TP), available phosphorus (AP), total potassium (TK), and available potassium (AK) were determined, and near-infrared (NIR) and attenuated total reflectance mid-infrared (ATR-MIR) spectra were acquired. Spectral preprocessing was performed, followed by variable selection using uninformative variable elimination (UVE) and competitive adaptive reweighted sampling (CARS). Partial least squares regression (PLSR) and random forest (RF) models were developed for single-modality spectra, and three fusion schemes-data-level, feature-level, and decision-level-were further designed. Model performance was evaluated on an independent validation set using RV2, RMSEV, and RPIQV, with RPIQV=1.4 as the usability threshold. The results demonstrated substantial differences in predictability among nutrient indicators. SOM, TN, and TK achieved stable performance on the independent validation set. The best SOM model was obtained from the NIR single-modality approach (PLSR, RV2=0.939, RPIQV=4.87), while data-level fusion yielded comparable accuracy (PLSR, RV2=0.936, RPIQV=4.75). The best results for TN and TK were both achieved using the ATR-MIR single-modality strategy (TN: RF, RV2=0.866, RPIQV=4.10; TK: PLSR, RV2=0.849, RPIQV=4.08). HN and AK reached a moderate prediction level (HN: RPIQV=2.42; AK: RPIQV=2.33). In contrast, TP and AP did not meet the usability threshold under any strategy (best RPIQV for TP = 1.16; for AP = 0.81). Overall, single-modality NIR and ATR-MIR models can provide a rapid quantitative screening route for SOM, TN, and TK in continuous-cropping fields, whereas the benefits of fusion were indicator-dependent. Phosphorus-related indicators still require further optimization.

PMID 42462555
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PubMedCureus2026-07-17

Diagnostic and Therapeutic Challenges in Herpes Simplex Virus-Triggered Anti-N-Methyl-D-Aspartate Receptor Encephalitis Presenting as Acute Psychiatric Illness in a Young Woman: A Case Report.

Rathi Pratik P, Shaikh Fahad Idrees FI, Manohar Tanuja T, Agrawal Arvind A et al.

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is a severe form of autoimmune encephalitis. Symptoms include psychiatric manifestations, seizures, dyskinesias, autonomic instability, and altered consciousness. Recently, Herpes simplex virus (HSV) encephalitis has been recognised as a major cause of secondary autoimmune encephalitis. We report the case of a 23-year-old woman who developed behavioural changes and altered sensorium. She was initially suspected of having a primary psychiatric disorder. Subsequent tests showed the presence of anti-NMDAR antibodies in the cerebrospinal fluid (CSF), and positivity for HSV-1 was confirmed by real-time polymerase chain reaction (PCR). Despite receiving high-dose corticosteroids, IVIG, plasmapheresis, rituximab, acyclovir, and antiviral therapy, the patient was admitted to the ICU, where she stayed for a prolonged period due to respiratory failure, septic shock, and acute kidney injury. This case highlights the diagnostic challenge between viral and autoimmune encephalitis and underlines that patients with acute neuropsychiatric symptoms require early recognition, repeated CSF testing, and multidisciplinary management.

PMID 42465184
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PubMedFrontiers in immunology2026-07-17

Rapid, non-invasive, visual point-of-care detection of koi herpesvirus using loop-mediated isothermal amplification.

Jiang Na N, Luo Jianlin J, Kong Chuiyu C, Ma Zhihong Z et al.

Koi herpesvirus (KHV or CyHV-3) causes a highly contagious and lethal disease in common carp and koi, resulting in substantial economic losses in global aquaculture. Rapid point-of-care testing (POCT) of KHV is critical for curbing its spread and preventing outbreaks. However, conventional diagnostic approaches, such as TaqMan quantitative PCR (qPCR), require professional personnel and specialized equipment, limiting their on-site applicability. A rapid visual POCT assay was developed by combing loop-mediated isothermal amplification (LAMP) with non-invasive mucus swab sampling. Two optimized release solutions enabled one-step nucleic acid preparation within 5 min. Among five primer sets designed, the optimal set targeting the thymidine kinase (TK) gene was selected for isothermal amplification at 65 °C for 60 min. The assay was further adapted for naked-eye result interpretation using a pH-sensitive indicatior dye. The assay demonstrated a detection limit of 21.42 copies/μL, with a 95% confidence interval of 14.88-41.83 copies/μL. No cross-reactivity was observed with seven common fish pathogens. Comparative evaluation with TaqMan qPCR using parallel clinical specimens yielded 100% concordant results. The total detection time was 65 min, enabling the POCT implementation across diverse scenarios. This non-invasive, visual LAMP-based POCT platform provides a sensitive, specific and equipment-free diagnostic strategy for KHV detection, facilitating timely disease surveillance, outbreak control management, and aquaculture biosecurity.

PMID 42465764
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PubMedBlood advances2026-07-17

Clinical outcomes of lentiviral gene therapy for SCD.

Booth Claire C, Jacobsohn David D

PMID 42467454
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