Phase Ib study of talimogene laherparepvec in combination with atezolizumab in patients with triple negative breast cancer and colorectal cancer with liver metastases.

BACKGROUND: Talimogene laherparepvec (T-VEC), a first-in-class oncolytic viral immunotherapy, enhances tumor-specific immune activation. T-VEC combined with atezolizumab, which blocks inhibitor T-cell checkpoints, could provide greater benefit than either agent alone. Safety/efficacy of the combination was explored in patients with triple negative breast cancer (TNBC) or colorectal cancer (CRC) with liver metastases. METHODS: In this phase Ib, multicenter, open-label, parallel cohort study of adults with TNBC or CRC with liver metastases, T-VEC (106 then 108 PFU/ml; ≤4 ml) was administered into hepatic lesions via image-guided injection every 21 (±3) days. Atezolizumab 1200 mg was given on day 1 and every 21 (±3) days thereafter. Treatment continued until patients experienced dose-limiting toxicity (DLT), had complete response, progressive disease, needed alternative anticancer treatment, or withdrew due to an adverse event (AE). The primary endpoint was DLT incidence, and secondary endpoints included efficacy and AEs. RESULTS: Between 19 March 2018 and 6 November 2020, 11 patients with TNBC were enrolled (safety analysis set: n = 10); between 19 March 2018 and 16 October 2019, 25 patients with CRC were enrolled (safety analysis set: n = 24). For the 5 patients in the TNBC DLT analysis set, no patient had DLT; for the 18 patients in the CRC DLT analysis set, 3 (17%) had DLT, all serious AEs. AEs were reported by 9 (90%) TNBC and 23 (96%) CRC patients, the majority with grade ≥3 [TNBC, 7 (70%); CRC, 13 (54%)], and 1 was fatal [CRC, 1 (4%)]. Evidence of efficacy was limited. Overall response rate was 10% (95% confidence interval 0.3-44.5) for TNBC; one (10%) patient had a partial response. For CRC, no patients had a response; 14 (58%) were unassessable. CONCLUSIONS: The safety profile reflected known risks with T-VEC including risks of intrahepatic injection; no unexpected safety findings from addition of atezolizumab to T-VEC were observed. Limited evidence of antitumor activity was observed.

[Varicella gastritis under immunosuppression : Case report of a woman after lung transplantation due to granulomatosis with polyangiitis]. / Varizella-Gastritis unter Immunsuppression : Kasuistik einer Patientin nach Lungentransplantation bei Granulomatose mit Polyangiitis.

A 35-year-old woman who had previously undergone a lung transplantation presented with severe abdominal pain and vomiting. The gastroscopy showed diffuse ulcerative gastric lesions. Tests for varicella zoster virus and Epstein-Barr virus via polymerase chain reactions (PCR) on endoscopically obtained gastric biopsies were found to be positive and confirmed varicella gastritis. Intravenous antiviral therapy with acyclovir was administered resulting in a normalization of all clinical symptoms, especially of abdominal pain and inflammation parameters.

Efficacy and safety of telaprevir (TVR) triple therapy in a 'real-life' cohort of 102 patients with HCV genotype 1: interim analysis after 24 weeks of treatment.

Since 2011, telaprevir (TVR)-based triple therapy is the new treatment standard for hepatitis C genotype 1 virus infection. The aim of our retrospective interim analysis encompassing the first 24 weeks on TVR-based triple therapy was to assess 'real-life' antiviral efficacy and side effects in a large single-centre cohort, both in comparison with the data obtained in large prospective clinical trials. In total, we treated 102 patients: 24 treatment-naïve patients, 58 patients pretreated with PEG-IFN/RBV (thereof: 28 with nonresponse, 25 with relapse, five unknown) and 20 patients who previously had received nonpegylated interferon. 74 of 102 patients were assigned with HCV genotype 1b; 34 of 102 patients were treated in the context of liver cirrhosis. 72 of 102 patients have reached treatment week 24 (mean treatment duration 31 weeks). In the ITT analysis, overall response rates were at: week 4: 66%; week 12: 85%; and week 24: 78%. So far, 24 patients discontinued treatment prematurely, of those, 10 patients were due to virological failure. Haematological side effects were frequent (40% anaemia), as were 'flu-like' symptoms (94%), rash (65%) and pruritus (79%). According to our interim ITT analysis encompassing up to 24 weeks of TVR-based triple therapy, our 'real-life' antiviral effects are comparable to the results of large multicentric clinical trials. However, TVR-based triple therapy exhibited a high frequency of side effects requiring multiple therapeutic interventions. Notably, in our 'real-life' cohort, no lethal case was observed so far.

Treatment of recurrent genotype 1 hepatitis C post-liver transplantation: single center experience with telaprevir-based triple therapy.

Recurrent HCV infection post-liver transplantation (post-LT) is still a major challenge in the treatment of hepatitis C virus (HCV) infection. In this retrospective analysis we gathered data about treatment response and safety of all 14 post-LT patients who were treated between 2011 and 2013 at our centre with a telaprevir (TVR)-based triple therapy. Seven out of 14 patients completed the full treatment course of 48 weeks. Five patients achieved a SVR 24, while 3 additional HCV RNA-negative patients are still in follow-up (end of treatment, SVR 12 and 22). Four patients discontinued treatment prematurely due to side effects. A virological non-response at TW 4 was seen in 1 patient. Virological breakthrough was observed in 2 patients at TW 16 and 28, respectively; 1 patient displayed a virological relapse after the end of treatment (EOT). Patients with a complicated course post-LT accumulated most of the severe side effects, largely infections. One patient with cholestatic hepatitis died 11 weeks after discontinuation of treatment due to progressive graft failure. In conclusion, TVR-based triple therapy in post-LT patients reveals an acceptable antiviral efficacy. Unfortunately, severe side effects are frequent and often require therapeutic interventions. Therefore, with the approval of less straining DAA like sofosbuvir in sight, TVR-based triple therapy in post-LT patients should be, if possible avoided.

Enhanced killing of ovarian carcinoma using oncolytic measles vaccine virus armed with a yeast cytosine deaminase and uracil phosphoribosyltransferase.

OBJECTIVE: To preclinical assess the feasibility of combining oncolytic measles vaccine virus (MeV) with suicide gene therapy for ovarian cancer treatment. METHODS: We genetically engineered a recombinant MeV armed with a yeast-derived bifunctional suicide gene that encodes for cytosine deaminase and uracil phosphoribosyltransferase (MeV-SCD). From this suicide gene, a chimeric protein is produced that converts the non-toxic prodrug 5-fluorocytosine (5-FC) into highly cytotoxic 5-fluorouracil (5-FU) and directly into 5-fluorouridine monophosphate (5-FUMP) thereby bypassing an important mechanism of chemoresistance to 5-FU. RESULTS: MeV-SCD was demonstrated to infect, replicate in and effectively lyse not only human ovarian cancer cell lines, but also primary tumor cells (albeit at lower efficiencies) that were derived from malignant ascites of ovarian cancer patients. Addition of the prodrug 5-FC significantly enhanced cell killing. Importantly, precision-cut tumor slices of human ovarian cancer patient specimens were efficiently infected with MeV-SCD. The prodrug-converting enzyme SCD was expressed by all infected tumor slices, thereby ensuring provision of the suicide gene arming function in patient-derived materials. CONCLUSIONS: With respect to safety and therapeutic impact, arming of oncolytic measles vaccine virus warrants further clinical investigation for ovarian cancer treatment.

An armed oncolytic measles vaccine virus eliminates human hepatoma cells independently of apoptosis.

Due to late diagnosis and a pronounced chemoresistance, most patients with hepatocellular carcinoma (HCC) have an overall poor prognosis. Measles vaccine viruses (MeV) have been shown to possess anti-tumor properties and their efficacy has been enhanced by arming with suicide genes. To test armed MeV for the treatment of HCC, we equipped it with the suicide gene Super-cytosine deaminase (SCD) and tested the efficacy in cell culture and in a mouse xenograft model of human HCC. Prodrug conversion was investigated in cell culture and quantified by high-performance liquid chromatography. We observed a strong oncolytic activity of MeV-SCD against human HCC in vitro and in vivo. The prodrug was efficiently converted in infected cells leading to a significant enhancement of the cytotoxic effect. Treatment of HCC xenografts with MeV caused long-term virus replication in tumor tissue. We show that the suicide gene therapy induces an apoptosis-like cell death but is not dependent on intact apoptosis pathways. These results demonstrate that MeV-based suicide gene therapy is a promising novel therapy regimen for HCC overcoming resistance towards conventional therapy. The independence from apoptosis raises hopes for the treatment of patients whose tumor cells exert defects in this cell death mechanism.

Direct and long-term detection of gene doping in conventional blood samples.

The misuse of somatic gene therapy for the purpose of enhancing athletic performance is perceived as a coming threat to the world of sports and categorized as 'gene doping'. This article describes a direct detection approach for gene doping that gives a clear yes-or-no answer based on the presence or absence of transgenic DNA in peripheral blood samples. By exploiting a priming strategy to specifically amplify intronless DNA sequences, we developed PCR protocols allowing the detection of very small amounts of transgenic DNA in genomic DNA samples to screen for six prime candidate genes. Our detection strategy was verified in a mouse model, giving positive signals from minute amounts (20 µl) of blood samples for up to 56 days following intramuscular adeno-associated virus-mediated gene transfer, one of the most likely candidate vector systems to be misused for gene doping. To make our detection strategy amenable for routine testing, we implemented a robust sample preparation and processing protocol that allows cost-efficient analysis of small human blood volumes (200 µl) with high specificity and reproducibility. The practicability and reliability of our detection strategy was validated by a screening approach including 327 blood samples taken from professional and recreational athletes under field conditions.

[Thrombotic microangiopathy under an effective treatment with gemcitabine]. / Thrombotische Mikroangiopathie unter einer effektiven Therapie mit Gemcitabin.

A 67-year-old male patient with a pancreatic carcinoma and hepatic metastases was admitted with progressive dyspnea and anuria. Previously he had received five cycles of a palliative chemotherapy with gemcitabine and responded well with a reduction of the tumor mass. The laboratory results showed a distinct anemia, thrombocytopenia, an increase in creatinine and lactate dehydrogenase levels. With an additional finding of 21 per mille fragmentocytes in the periphery blood smear, we diagnosed a thrombotic microangiopathy (TMA). Until now the literature lacks well-defined therapy standards for this known but rare condition of gemcitabine. In a few case reports addressing the related microangiopathy of thrombotic thrombocytopenic purpura (TTP), which is characterised by a significant reduction of the von Willebrand factor (vWF) cleaving serum protease ADAMTS-13, encouraging results have been achieved by an immediate plasma exchange. Though ADAMTS-13 activity was not relevantly reduced in our patient, we still observed a rapid improvement of the clinical features as well as of LDH, thrombocytes and fragmentocytes under plasma exchange. The patient was discharged after one month in good clinical condition. Interestingly, during follow-up for further 21 months we found a continued stable status of the pancreatic carcinoma without any cytostatic therapy. In summary, this case provides evidence that the use of plasma exchange therapy in gemcitabine-associated TMA is justified.

[Anti-angiogenic therapy for gastrointestinal tumours]. / Antiangiogene Therapie gastrointestinaler Tumoren.

New therapeutic strategies that notably lack cross resistance with established treatment regimens are much needed in gastroenterological oncology. One such approach is therapeutic anti-angiogenesis which aims at the inhibition of vasculature growth in solid tumours. Since numerous gastrointestinal tumours show strong tumour neoangiogenesis and consequently are highly vascularised, anti-angiogenic therapies will play a pivotal role in tomorrow's gastroenterological oncology. Hence, this review covers (i) basic mechanisms of tumour angiogenesis, (ii) recent anti-angiogenic strategies in the field of gastroenterological oncology as well as (iii) a discussion of their current limitations and perspectives.

Contrast enhanced MR-guided biopsy of hepatocellular carcinoma.

Magnetic resonance (MR)-guided liver biopsy was performed in three patients with hepatocellular carcinoma. The tumor was considered (n = 2) or proven (n = 1) inaccessible with ultrasound or computed tomographic guidance. Because all lesions were poorly delineated on nonenhanced MR imaging, contrast agents (Gd-BOPTA, n = 1; ferucarbotran, n = 2) were applied to facilitate biopsy in an open low-field scanner. Postcontrast tumor conspicuity was fair in the patient receiving Gd-BOPTA and excellent in both patients receiving ferucarbotran, and biopsy was successful in all cases.

Reduced toxicity of F-deficient Sendai virus vector in the mouse fetus.

Current concerns over insertional mutagenesis by retroviral vectors mitigate investigations into alternative, potentially persistent gene therapy vector systems not dependent on genomic integration, such as Sendai virus vectors (SeVV). Prenatal gene therapy requires efficient gene delivery to several tissues, which may not be achievable by somatic gene transfer to the adult. Initially, to test the potential and tropism of the SeVV for gene delivery to fetal tissues, first-generation (replication- and propagation-competent) recombinant SeVV, expressing beta-galactosidase was introduced into late gestation immunocompetent mice via the amniotic and peritoneal cavities and the yolk sac vessels. At 2 days, this resulted in very high levels of expression particularly in the airway epithelium, mesothelium and vascular endothelium, respectively. However, as expected, substantial vector toxicity was observed. The efficiency of gene transfer and the level of gene expression were then examined using a second-generation SeVV. The second generation was developed to be still capable of cytoplasmic RNA replication and therefore high-level gene expression, but incapable of vector spread due to lack of the gene for viral F-protein. Vector was introduced into the fetal amniotic and peritoneal cavities, intravascularly, intramuscularly and intraspinally; at 2 days, expression was observed in the airway epithelia, peritoneal mesothelia, unidentified cells in the gut wall, locally at the site of muscle injection and in the dorsal root ganglia, respectively. Mortality was dramatically diminished compared with the first-generation vector.

[Oncolytic viruses for genetic therapy of gastrointestinal tumors]. / Onkolytische Viren als innovativer Ansatz in der Therapie gastrointestinaler Tumoren.

Gastroenterological oncology requires new strategies with new mechanisms of action and without cross-resistance to currently available treatment regimes. Virotherapy which is based on the employment of replication-competent viral vectors exhibiting strong oncolytic properties is such an approach currently under preclinical/clinical investigation. Techniques of molecular virology are required for further improvement of current vectors, particularly with respect to oncolytic activity, tumour selectivity, tumour spread capacity, and safety.

HSV-1 VP22 augments adenoviral gene transfer to CNS neurons in the retina and striatum in vivo.

One of the obstacles to efficient vector-mediated gene transfer to the CNS is limited transduction of target neurons. The VP22 tegument protein of HSV-1 can cross biological membranes and translocate the VP22 protein from primarily transfected cells to many surrounding cells in vitro. Here, we employed an adenoviral vector coding for a VP22-GFP fusion protein driven by a CMV promoter to test its capability of transducing CNS neurons in vivo. Intraocular administration of Ad.VP22-GFP in the rat doubled both the retinal area containing transduced, GFP-expressing cells and the absolute number of GFP-expressing retinal neurons compared to Ad.GFP transduction. Following injection of Ad.VP22-GFP into the mouse brain, the transduced striatal area was increased by a factor of 7 compared to intracerebral injection of Ad.GFP. In both retina and striatum, GFP-expressing cells were identified as mainly neurons. Thus, VP22 greatly augments adenovirus-mediated transgene delivery to CNS neuronsin vivo, making VP22 a promising tool for enhancing the efficacy of adenoviral gene transfer of protective factors to the CNS.

Enhanced suicide gene effect by adenoviral transduction of a VP22-cytosine deaminase (CD) fusion gene.

The low transduction efficiency of viral and nonviral vectors is a major limitation in tumour gene therapy. The HSV-1 tegument protein VP22 has been shown to exhibit a novel intercellular transport property. VP22 wild-type as well as VP22 fusion proteins efficiently spread from the original expressing cell to numerous neighbouring cells, so that protein transport by VP22 chimaeric polypeptides into the surrounding cells offers a possible compensation for the inadequate gene transfer efficiencies. To improve the therapeutic efficacy of the E. coli cytosine deaminase (CD) suicide gene we made use of the VP22 transport property in CD transducing adenoviral (Ad) vectors. C- and N-terminal fusions of CD linked in-frame with VP22 were generated and cloned into recombinant adenoviral vectors. Following in vitro transduction immunofluorescence analysis of Ad-transduced producer cells coplated with naive cells confirmed that the characteristic foci pattern of central producer and adjoining neighbour cells displaying nuclear staining was retained. After transduction of rat hepatoma cells with adenoviral vectors and subsequent incubation with the prodrug 5-FC, we observed enhanced cell cytotoxicity when comparing the CD-VP22 fusion (Ad-CD-VP22) with Ad-vectors expressing the CD gene only (Ad-CD). Thereby employment of Ad-vectors encoding VP22 fusion proteins opens up new possibilities to potentiate the efficiency of suicide gene therapy for the treatment of solid tumours.

A prototype transduction tag system (delta LNGFR/NGF) for noninvasive clinical gene therapy monitoring.

The dramatic expansion of clinical gene therapy trials requires the development of noninvasive clinical monitoring procedures, which provide information about expression levels, expression kinetics, and spatial distribution of transduced therapeutic genes. With the development of such procedures, invasive sampling of tissue probes from patients potentially could be reduced significantly. In this study, an experimental platform for the rational design and in vitro testing of suitable receptor-ligand couples as components of future transduction tag systems for noninvasive gene therapy monitoring applications was developed. Initially, the feasibility of the delta LNGFR/nerve growth factor (NGF) transduction tag system was investigated; this system employs a mutated version of the low-affinity nerve growth factor receptor (p75mut or delta LNGFR) lacking the entire cytoplasmic domain. Specific binding of 125I-radiolabeled NGF was demonstrated for two stable delta LNGFR-transduced cell lines, but not for delta LNGFR-negative parental control cell lines. An additional binding analysis performed in a MicroImager directly confirmed binding of radiolabeled ligands (125I-NGF, 125I-anti-p75 monoclonal antibody) to the p75mut expressed on intact target cells, but not on control cells. Subsequent binding studies employing NGF radiolabeled with the positron-emitting isotope 124I demonstrated a specific binding for LNGFR+ PC12 cells. Consequently, the first in vitro proof of a transduction tag approach based on the specificity of the 124I-NGF/LNGFR interaction was provided, which opens up the possibility for future noninvasive positron emission tomography monitoring in clinical gene therapy trials.