Drug Database
HS

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

PubMedHealth science reports2026-11-11

Awareness and Acceptance of Gene Therapy for Sickle Cell Disease Among Individuals From the Eastern Province of Saudi Arabia: A Cross-Sectional Study.

Alrezq Dana A DA, Al Darwish Fatimah J FJ, Almatrood Naba A NA, Aljowaid Marwa A MA et al.

Public acceptance is important for implementing gene therapy for sickle cell disease (SCD), particularly in regions with a high disease burden. This study assessed self-perceived knowledge, misconceptions, health literacy, quality of life, and attitudes toward SCD gene therapy among adults from or residing in the Eastern Province of Saudi Arabia. In this cross-sectional study, 1005 adults completed a structured questionnaire between June and November 2025. Measures included SCD history, perceived knowledge and attitudes toward gene therapy, HLS-SF12 health literacy, and EQ-5D-5L/EQ-VAS health status. Associations were examined using non-parametric tests and multivariable regression models. Self-perceived knowledge of gene therapy side effects was consistently the lowest across all educational levels, with a median score of 0. Overall self-perceived knowledge showed weak positive correlations with gene therapy attitudes (ρ = 0.11-0.19). Higher health literacy was associated with more favorable attitude and knowledge outcomes; adjusted ORs for outcomes meeting the proportional-odds assumption ranged from 1.60 to 2.32 (all p < 0.001). For community acceptability, the health literacy effect varied across thresholds, with adjusted ORs ranging from 1.62 to 2.86 (overall p < 0.001). Among participants with low community acceptability, reported concerns were associated with willingness and family discussion outcomes, although effect sizes were small (ε2 = 0.009-0.015). Participants with SCD also reported lower EQ-VAS scores than those without SCD (median 85 vs 90; p = 0.008). Important gaps remain in patients' perceived knowledge of gene therapy, particularly regarding side effects. Health literacy was consistently associated with more favorable knowledge and attitudes, although several associations were small. These findings support targeted education addressing knowledge gaps, uncertainty, and relevant sociocultural concerns.

PMID 43011792
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PubMedGene therapy2026-11-11

Perspectives on cell and gene therapy: insights from the 5th China Annual Congress on CGT.

Xu Yan Y, Chen Liang L, Hu Ping P, Wang Haopeng H et al.

Cell and gene therapy (CGT) represents a paradigm shift in medicine, offering immense potential to correct inherited genetic defects and provide healthy or empowered cells for therapy, thereby revolutionizing the treatment of cancers, chronic diseases, and hereditary diseases. Against a backdrop of rapid technological advancements and accelerating commercialization in the field, the 5th China Annual Congress on Cell and Gene Therapy was held in Haikou, Hainan, from November 20 to 22, 2025. At the congress, 175 speakers from around the world gave presentations on immune cell therapeutics, gene therapy, stem cell-based regenerative medicine, and regulatory frameworks alongside industrialization. These presentations highlighted that immune cell therapies are expanding beyond hematologic malignancies into solid tumors and autoimmune diseases. Concurrently, gene therapy has demonstrated promising clinical efficacy in treating genetic disorders alongside the evolution of therapeutic tools, while stem cell-based regenerative medicine has advanced both in fundamental research and in clinical translation for tissue repair. The congress also addressed the current status and challenges of China's regulatory system and industrialization landscape. Although the preliminary clinical outcomes of most reported CGT therapies are encouraging, long-term efficacy and safety require further observation. Furthermore, critical challenges remain, including the absence of harmonized potency assays and interoperable real-world evidence systems, manufacturing scalability and cost barriers, and the need for further refinement of the regulatory framework to accommodate rapid technological evolution. This report summarizes the key advancements and outstanding issues discussed at the congress, aiming to facilitate the sustainable and robust development of the CGT field.

PMID 43009539
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PubMedCancer drug resistance (Alhambra, Calif.)2026-11-11

Randomized multicentre Phase 2 clinical trial of non-viral gene therapy for pancreatic cancer: clinical and molecular findings.

Buscail Louis L, Lebrin Marine M, Hanoun Naima N, Gourgou Sophie S et al.

Aim: Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis, and innovative therapies are needed. We developed a phase I pilot, non-viral gene therapy (CYL-02) encoding SST2 and DCK::UMK genes complexed with a polyethyleneimine non-viral vector to sensitize tumours to gemcitabine chemotherapy, which showed excellent feasibility and safety. Methods: An open-label, multicentre, randomized Phase 2 trial (NCT02806687) compared CYL-02 [two intratumoral endoscopic ultrasound (EUS)-guided injections one month apart] + gemcitabine injected weekly vs. gemcitabine alone in 70 patients (n = 35 per arm) with locally advanced PDAC. The primary endpoint was progression-free survival (PFS). Secondary endpoints were overall survival (OS), tumour response, safety, and ancillary studies. Results: PFS did not differ between arms. Unexpectedly, OS was worse in the gene therapy + chemotherapy arm. Exploratory analyses revealed no differences in clinical status, baseline characteristics, or the number of patients receiving second-line therapy, with the exception of a more frequent use of FOLFOX post-progression in the control arm, which could explain this difference. Proteomic profiling identified clusterin (CLU) as a candidate treatment-induced resistance factor in patients: CYL-02 + gemcitabine significantly increased circulating CLU levels, while gemcitabine alone did not. In vitro and in vivo models confirmed CLU induction by DCK combined with gemcitabine and demonstrated that CLU silencing restored chemosensitivity, reducing experimental tumour volume in mice. Conclusion: CLU induction in patients receiving CYL-02 and gemcitabine may explain adaptive resistance and lack of efficacy of gene therapy. These results provide a rationale for combining CYL-02 and gemcitabine with CLU targeting to overcome resistance in pancreatic cancer.

PMID 43011677
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PubMed[Zhonghua yan ke za zhi] Chinese journal of ophthalmology2026-11-11

[The key factors affecting the efficacy of optogenetic therapy for retinitis pigmentosa].

Lu P R PR, Han X X, Zhu Z Q ZQ

Retinitis pigmentosa (RP) is a genetically heterogeneous retinal degenerative disease caused by the progressive loss of photoreceptor cells and atrophy of the retinal pigment epithelium, which eventually leads to bilateral blindness. As an emerging pan-gene therapeutic approach, optogenetic therapy holds the potential to restore visual function by introducing exogenous photosensitive protein genes into non-photoreceptive retinal neurons. However, the high heterogeneity of RP phenotypes and pathogenic genes causes significant differences in therapeutic benefits among patients treated with optogenetic therapy. This article systematically analyzes the key factors influencing the efficacy of optogenetic therapy for RP from multiple dimensions, including the type and status of target cells, immune responses to adeno-associated virus, ocular complications of advanced RP, administration routes and intervention time windows. It aims to provide a theoretical foundation and practical reference for optimizing the clinical application of optogenetic therapy.

PMID 43010769
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PubMedReumatismo2026-11-11

Atypical adult polyarteritis nodosa unmasking deficiency of adenosine deaminase 2: a case report about the importance of genetic testing in adults.

Antolini Sofia S, Cassandrini Denise D, Bindoli Sara S, Bronte Vincenzo V et al.

Deficiency of adenosine deaminase 2 (DADA2) is an autosomal recessive autoinflammatory disorder caused by biallelic mutations in the ADA2 gene. It presents as a monogenic vasculitis with heterogeneous manifestations that often resemble small- and medium-vessel vasculitis, particularly polyarteritis nodosa (PAN)-like disease, leading to frequent misdiagnosis, especially in adults. Early recognition of DADA2 is crucial, as prompt treatment can control inflammation, preserve vascular integrity, and prevent irreversible organ damage.  Rising awareness of the wide clinical spectrum of DADA2 is fundamental to improve recognition and facilitate timely diagnosis, ultimately enhancing prognosis. We herein describe the case of a middle-aged woman with skin lesions, central nervous system, peripheral nervous system, and gastrointestinal tract ischemic manifestations who was initially diagnosed with PAN. The patient was treated with glucocorticoids as well as several steroid-sparing immunosuppressive agents (methotrexate, azathioprine, rituximab, tocilizumab, and cyclophosphamide), which all proved to be ineffective. Meanwhile, the patient developed cytopenias and hypogammaglobulinemia. Subsequent genetic testing identified a homozygous missense mutation in the ADA2 gene (c.1358A>G, p.Tyr453Cys), supporting the diagnosis of DADA2 and enabling the initiation of effective therapy with the tumor necrosis factor-α inhibitor etanercept. This case underscores the importance of considering DADA2 in adult patients presenting with recurrent vasculitic manifestations refractory to conventional immunosuppressive therapy, as timely genetic testing can be pivotal in redirecting treatment toward targeted and effective therapy.

PMID 43010799
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PubMedeLife2026-11-11

Multimodal single-cell analyses reveal distinct fusion-regulated transcriptional programs in Ewing sarcoma.

Waltner Olivia G OG, Apfelbaum April A AA, Wrenn Emma D ED, Bhise Shruti S SS et al.

Ewing sarcoma (EwS) is a fusion-driven malignancy, peaking in adolescence. Although EwS tumors are driven uniquely by EWS::FLI1 and related fusions, patient outcomes vary greatly. If and how tumor plasticity of EWS::FLI1-regulated transcriptional signatures contributes to disease progression is not known. To address this, we utilized a single-cell co-assay of RNA and chromatin accessibility (ATAC) sequencing to identify gene regulatory networks in EwS. By comprehensively characterizing regulatory elements across cell lines, we identified multiple unique modules of gene regulation. Differential usage and prevalence of these modules was evident across cell lines, associated with distinct epigenetic and transcriptomic signatures, and in specific cases, modifiable by exogenous TGF-β. When we examined primary EwS patient tumors, we observed these same regulatory modules were variably enriched both across and within tumors, highlighting the existence of intratumoral heterogeneity in gene regulatory networks. Our findings demonstrate that multiple, co-existing transcriptional programs shape the phenotypic diversity of EwS and suggest that the balance between these networks may have important implications for clinical outcomes and targeted therapy development.

PMID 43012345
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