Toca 511 (vocimagene amiretrorepvec), a nonlytic, amphotropic retroviral replicating vector (RRV), encodes and delivers a functionally optimized yeast cytosine deaminase (CD) gene to tumors. In ...orthotopic glioma models treated with Toca 511 and 5-fluorocytosine (5-FC) the CD enzyme within infected cells converts 5-FC to 5-fluorouracil (5-FU), resulting in tumor killing. Toca 511, delivered locally either by intratumoral injection or by injection into the resection bed, in combination with subsequent oral extended-release 5-FC (Toca FC), is under clinical investigation in patients with recurrent high-grade glioma (HGG). If feasible, intravenous administration of vectors is less invasive, can easily be repeated if desired, and may be applicable to other tumor types. Here, we present preclinical data that support the development of an intravenous administration protocol. First we show that intravenous administration of Toca 511 in a preclinical model did not lead to widespread or uncontrolled replication of the RVV. No, or low, viral DNA was found in the blood and most of the tissues examined 180 days after Toca 511 administration. We also show that RRV administered intravenously leads to efficient infection and spread of the vector carrying the green fluorescent protein (GFP)-encoding gene (Toca GFP) through tumors in both immune-competent and immune-compromised animal models. However, initial vector localization within the tumor appeared to depend on the mode of administration. Long-term survival was observed in immune-competent mice when Toca 511 was administered intravenously or intracranially in combination with 5-FC treatment, and this combination was well tolerated in the preclinical models. Enhanced survival could also be achieved in animals with preexisting immune response to vector, supporting the potential for repeated administration. On the basis of these and other supporting data, a clinical trial investigating intravenous administration of Toca 511 in patients with recurrent HGG is currently open and enrolling.
We developed a Moloney mouse leukemia virus (MLV)-based retroviral replicating vector (RRV), Toca 511, which has displayed tumor specificity in resected brain tumor material and blood in clinical ...trials. Here, we investigated the interaction between Toca 511 and human host cells, and we show that RRVs do not induce type I interferon (IFN) responses in cultured human tumor cells or cultured human primary cells. However, exogenous type I IFN inhibited RRV replication in tumor cells and induced IFN-regulated genes, albeit at a lower level than in primary cells. Unexpectedly, RRVs did not induce IFN-α production upon incubation in vitro with human plasmacytoid dendritic cells (pDCs), whereas lentivirus vector and heat-treated RRVs did. Coincubation of RRVs with heat-treated RRVs or with lentivirus vector suppressed IFN-α production in pDCs, suggesting that native RRV has a dominant inhibitory effect on type I IFN induction. This effect is sensitive to trypsin treatment. In addition, heat treatment inactivated that activity but exposed an immune-stimulatory activity. The immune-stimulating component is sensitive to deglycosidases, trypsin, and phospholipase C treatment. Experiments with retroviral nonreplicating vectors and virus-like particles demonstrated that the immunosuppressive activity is not associated with the amphotropic envelope or the glyco-Gag protein. In summary, our data provide evidence that RRVs do not directly trigger type I IFN responses in IFN-responsive tumor cells. Moreover, RRVs appear to carry a heat-labile component that actively suppresses activation of cellular innate immune responses in pDCs. Inhibition of IFN induction by RRVs and the reduced response to IFN should facilitate tumor-specific infection in vivo.
RRVs have a convincing preference for replicating in tumor cells in animal models, and we observed similar preferences in the initial treatment of human glioblastoma patients. This study investigates the basis for the interaction between RRV and human host cells (tumor versus nontumor) in vitro. We found that RRVs do not trigger an IFN-α/β response in tumor cells, but the cells are capable of responding to type I IFNs and of producing them when stimulated with known agonists. Surprisingly, the data show that RRVs can actively inhibit induction of cellular innate immunity and that this inhibitory activity is heat labile and trypsin sensitive and not attributable to the envelope protein. These data partially explain the observed in vivo tumor specificity.
Toca 511, a gamma retroviral replicating vector encoding cytosine deaminase, used in combination with 5-fluorocytosine (5-FC) kills tumor by local production of 5-fluorouracil (5-FU), inducing local ...and systemic immunotherapeutic response resulting in long-term survival after cessation of 5-FC. Toca 511 and Toca FC (oral extended-release 5-FC) are under investigation in patients with recurrent high-grade glioma. Lomustine is a treatment option for patients with high-grade glioma.
We investigated the effects of lomustine combined with Toca 511 + 5-FC in syngeneic orthotopic glioma models. Safety and survival were evaluated in immune-competent rat F98 and mouse Tu-2449 models comparing Toca 511 + 5-FC to lomustine + 5-FC or the combination of Toca 511 + 5-FC + lomustine. After intracranial implantation of tumor, Toca 511 was delivered transcranially followed by cycles of intraperitoneal 5-FC with or without lomustine at the first or fourth cycle.
Coadministration of 5-FC with lomustine was well tolerated. In F98, combination Toca 511 + 5-FC and lomustine increased median survival, but "cures" were not achieved. In Tu-2449, combination Toca 511 + 5-FC and lomustine increased median survival and resulted in high numbers of cure. Rejection of tumor rechallenge occurred after treatment with Toca 511 + 5-FC or combined with lomustine, but not with lomustine + 5-FC. Mixed lymphocyte-tumor cell reactions using splenocytes from cured animals showed robust killing of target cells in an effector:target ratio-dependent manner with Toca 511 + 5-FC and Toca 511 + 5-FC + lomustine day 10.
The combination of Toca 511 + 5-FC and lomustine shows promising efficacy with no additive toxicity in murine glioma models. Immunotherapeutic responses resulting in long-term survival were preserved despite lomustine-related myelosuppression.
Patients with the most common and aggressive form of high-grade glioma, glioblastoma multiforme, have poor prognosis and few treatment options. In 2 immunocompetent mouse brain tumor models ...(CT26-BALB/c and Tu-2449-B6C3F1), we showed that a nonlytic retroviral replicating vector (Toca 511) stably delivers an optimized cytosine deaminase prodrug activating gene to the tumor lesion and leads to long-term survival after treatment with 5-fluorocytosine (5-FC). Survival benefit is dose dependent for both vector and 5-FC, and as few as 4 cycles of 5-FC dosing after Toca 511 therapy provides significant survival advantage. In the virally permissive CT26-BALB/c model, spread of Toca 511 to other tissues, particularly lymphoid tissues, is detectable by polymerase chain reaction (PCR) over a wide range of levels. In the Tu-2449-B6C3F1 model, Toca 511 PCR signal in nontumor tissues is much lower, spread is not always observed, and when observed, is mainly detected in lymphoid tissues at low levels. The difference in vector genome spread correlates with a more effective antiviral restriction element, APOBEC3, present in the B6C3F1 mice. Despite these differences, neither strain showed signs of treatment-related toxicity. These data support the concept that, in immunocompetent animals, a replicating retroviral vector carrying a prodrug activating gene (Toca 511) can spread through a tumor mass, leading to selective elimination of the tumor after prodrug administration, without local or systemic pathology. This concept is under investigation in an ongoing phase I/II clinical trial of Toca 511 in combination with 5-FC in patients with recurrent high-grade glioma (www.clinicaltrials.gov NCT01156584).
Potent immunosuppressive and regenerative properties of mesenchymal stem cells (MSCs) position them as a novel therapy for autoimmune diseases. This research examines the therapeutic effect of MSCs ...administration at different disease stages in experimental autoimmune encephalomyelitis (EAE). Classical and atypical scores of EAE, associated with Th1 and Th17 response, respectively, and also Treg lymphocytes, were evaluated. MSCs administration at the onset (EAE+MSConset) induced an important amelioration of the clinical signs and less lasting effect at the peak of EAE (EAE+MSCpeak). No effect was observed when MSCs were applied after EAE stabilization (EAE+MSClate). Surprisingly, EAE atypical signs were detected in EAE+MSCpeak and EAE+MSClate mice. However, no correlation was found in Th17/Th1 ratio. Interestingly, regardless of time administration, MSCs significantly reduced IL-6 and also T-bet, RORγT, and Foxp3 mRNA levels in brain samples of EAE mice. The downregulation of IL-6 could restore the well-functioning of the blood-brain barrier of EAE mice, correlated with a decreased number of brain infiltrating leukocytes. These results suggest that the inflammatory status is important to be considered for administering MSCs in autoimmune pathologies, leading to a further research to clarify the effect of MSCs for multiple sclerosis.
Introduction
Due to established teratogenicity of valproates, the EU risk minimisation measures (RMMs) with a pregnancy prevention programme (PPP) for valproate were updated in March 2018.
Objectives
...To investigate the effectiveness of the 2018 EU RMMs on valproate utilisation in five European countries/regions.
Methods
A multi-database, times series study of females of childbearing potential (12–55 years) was conducted using electronic medical records from five countries/regions (01.01.2010–31.12.2020): Denmark, Tuscany (Italy), Spain, the Netherlands, and the UK. Clinical and demographic information from each database was transformed to the ConcePTION Common Data Model, quality checks were conducted and a distributed analysis was performed using common scripts. Incident and prevalent use of valproate, proportion of discontinuers and switchers to alternative medicine, frequency of contraception coverage during valproate use, and occurrence of pregnancies during valproate exposure were estimated per month. Interrupted time series analyses were conducted to estimate the level or trend change in the outcome measures.
Results
We included 69,533 valproate users from 9,699,371 females of childbearing potential from the five participating centres. A significant decline in prevalent use of valproates was observed in Tuscany, Italy (mean difference post-intervention −7.7%), Spain (−11.3%), and UK (−5.9%) and a non-significant decline in the Netherlands (−3.3%), but no decline in incident use after the 2018 RMMs compared to the period before. The monthly proportion of compliant valproate prescriptions/dispensings with a contraceptive coverage was low (<25%), with an increase after the 2018 RMMs only in the Netherlands (mean difference post-intervention 12%). There was no significant increase in switching rates from valproates to alternative medicine after the 2018 intervention in any of the countries/regions. We observed a substantial number of concurrent pregnancies during valproate exposure, but with a declining rate after the 2018 RMMs in Tuscany, Italy (0.70 per 1000 valproate users pre- and 0.27 post-intervention), Spain (0.48 and 0.13), the Netherlands (0.34 and 0.00), and an increasing rate in UK (1.13 and 5.07).
Conclusion
There was a small impact of the 2018 RMMs on valproate use in the studied European countries/regions. The substantial number of concurrent pregnancies with valproate exposure warrants a careful monitoring of implementation of the existing PPP for valproate in clinical practice in Europe, to see if there is any need for additional measures in the future.
Resumen La presentación de pacientes con cuerpos extraños a nivel rectal no es poco frecuente; sin embargo, hay pocas estadísticas sobre la epidemiología de esta entidad. La mayor parte de la ...literatura publicada hace mención a reporte de casos o series de casos. Los cuerpos extraños rectales son insertados de forma intencional o no intencional, y constituyen un reto diagnóstico y terapéutico para el médico; por lo que el médico a cargo requiere de la habilidad y conocimiento para extraer objetos de diferentes formas y tamaños. Los cuerpos extraños rectales son generalmente observados en la población adulta; en relación con la estimulación erótica o asalto sexual. Adicionalmente, algunos cuerpos extraños pueden ser ingeridos ocasionalmente, pasando a través del tracto gastrointestinal y alojándose en el recto, aunque esta situación es la menos común; en especial en pacientes con enfermedades mentales, trastornos visuales, alcohólicos o usuarios de prótesis dentales. La finalidad de esta revisión es establecer unas pautas de manejo y dar a conocer un algoritmo para el enfoque de los cuerpos extraños colorrectales.
Background:
In March 2018, the European pregnancy prevention programme for oral retinoids was updated as part of risk minimisation measures (RMM), emphasising their contraindication in pregnant ...women.
Objective:
To measure the impact of the 2018 revision of the RMMs in Europe by assessing the utilisation patterns of isotretinoin, alitretinoin and acitretin, contraceptive measures, pregnancy testing, discontinuation, and pregnancy occurrence concomitantly with a retinoid prescription.
Methods:
An interrupted time series (ITS) analysis to compare level and trend changes after the risk minimisation measures implementation was conducted on a cohort of females of childbearing age (12–55 years of age) from January 2010 to December 2020, derived from six electronic health data sources in four countries: Denmark, Netherlands, Spain, and Italy. Monthly utilisation figures (incidence rates IR, prevalence rates PR and proportions) of oral retinoids were calculated, as well as discontinuation rates, contraception coverage, pregnancy testing, and rates of exposed pregnancies to oral retinoids, before and after the 2018 RMMs.
Results:
From 10,714,182 females of child-bearing age, 88,992 used an oral retinoid at any point during the study period (mean age 18.9–22.2 years old). We found non-significant level and trend changes in incidence or prevalence of retinoid use in females of child-bearing age after the 2018 RMMs. The reason of discontinuation was unknown in >95% of cases. Contraception use showed a significant increase trend in Spain; for other databases this information was limited. Pregnancy testing was hardly recorded thus was not possible to model ITS analyses. After the 2018 RMM, rates of pregnancy occurrence during retinoid use, and start of a retinoid during a pregnancy varied from 0.0 to 0.4, and from 0.2 to 0.8, respectively.
Conclusion:
This study shows a limited impact of the 2018 RMMs on oral retinoids utilisation patterns among females of child-bearing age in four European countries. Pregnancies still occur during retinoid use, and oral retinoids are still prescribed to pregnant women. Contraception and pregnancy testing information was limited in most databases. Regulators, policymakers, prescribers, and researchers must rethink implementation strategies to avoid any pregnancy becoming temporarily related to retinoid use.
Treatment of tumors with Toca 511, a gamma retroviral replicating vector encoding cytosine deaminase, followed by 5-fluorocytosine (5-FC) kills tumors by local production of 5-fluorouracil (5-FU). In ...brain tumor models, this treatment induces systemic anti-tumor immune responses and long-term immune-mediated survival. Phase 1 Toca 511 and Toca FC (extended-release 5-FC) clinical trials in patients with recurrent high-grade glioma show durable complete responses and promising survival data compared to historic controls. The work described herein served to expand on our earlier findings in two models of metastatic colorectal carcinoma (mCRC). Intravenous (i.v.) delivery of Toca 511 resulted in substantial tumor-selective uptake of vector into metastatic lesions. Subsequent treatment with 5-FC resulted in tumor shrinkage, improved survival, and immune memory against future rechallenge with the same CT26 CRC cell line. Similar results were seen in a brain metastasis model of mCRC. Of note, 5-FC treatment resulted in a significant decrease in myeloid-derived suppressor cells (MDSCs) in mCRC tumors in both the liver and brain. These results support the development of Toca 511 and Toca FC as a novel immunotherapeutic approach for patients with mCRC. A phase 1 study of i.v. Toca 511 and Toca FC in solid tumors, including mCRC, is currently underway (NCT02576665).
Toca 511 is a modified retroviral replicating vector based on Moloney γ-retrovirus with an amphotropic envelope. As an investigational cancer treatment, Toca 511 preferentially infects cancer cells ...without direct cell lysis and encodes an enhanced yeast cytosine deaminase that converts the antifungal drug 5-fluorocytosine to the anticancer drug, 5-fluorouracil. A panel of established human cancer cell lines, derived from glioblastoma, colon, and breast cancer tissue, was used to evaluate parameters critical for effective anticancer activity. Gene transfer, cytosine deaminase production, conversion of 5-fluorocytosine to 5-fluorouracil, and subsequent cell killing occurred in all lines tested. We observed >50% infection within 25 days in all lines and 5-fluorocytosine LD50 values between 0.02 and 6 μg/ml. Although we did not identify a small number of key criteria, these studies do provide a straightforward approach to rapidly gauge the probability of a Toca 511 and 5-fluorocytosine treatment effect in various cancer indications: a single MTS assay of maximally infected cancer cell lines to determine 5-fluorocytosine LD50. The data suggest that, although there can be variation in susceptibility to Toca 511 and 5-fluorocytosine because of multiple mechanistic factors, this therapy may be applicable to a broad range of cancer types and individuals.
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