Patients with Advanced or Metastasised Non-Small-Cell Lung Cancer with Viscum album L. Therapy in Addition to PD-1/PD-L1 Blockade: A Real-World Data Study.

Immunotherapy with PD-1/PD-L1 inhibitors has significantly improved the survival rates of patients with metastatic non-small-cell lung cancer (NSCLC). Results of a real-world data study investigating add-on VA (Viscum album L.) to chemotherapy have shown an association with the improved overall survival of patients with NSCLC. We sought to investigate whether the addition of VA to PD-1/PD-L1 inhibitors in patients with advanced or metastasised NSCLC would have an additional survival benefit. In the present real-world data study, we enrolled patients from the accredited national registry, Network Oncology, with advanced or metastasised NSCLC. The reporting of data was performed in accordance with the ESMO-GROW criteria for the optimal reporting of oncological real-world evidence (RWE) studies. Overall survival was compared between patients receiving PD-1/PD-L1 inhibitor therapy (control, CTRL group) versus the combination of anti-PD-1/PD-L1 therapy and VA (combination, COMB group). An adjusted multivariate Cox proportional hazard analysis was performed to investigate variables associated with survival. From 31 July 2015 to 9 May 2023, 415 patients with a median age of 68 years and a male/female ratio of 1.2 were treated with anti-PD-1/PD-L1 therapy with or without add-on VA. Survival analyses included 222 (53.5%) patients within the CRTL group and 193 (46.5%) in the COMB group. Patients in the COMB group revealed a median survival of 13.8 months and patients in the CRTL group a median survival of 6.8 months (adjusted hazard ratio, aHR: 0.60, 95% CI: 0.43-0.85, p = 0.004) after adjustment for age, gender, tumour stage, BMI, ECOG status, oncological treatment, and PD-L1 tumour proportion score. A reduction in the adjusted hazard of death by 56% was seen with the addition of VA (aHR 0.44, 95% CI: 0.26-0.74, p = 0.002) in patients with PD-L1-positive tumours (tumour proportion score > 1%) treated with first-line anti-PD-1/PD-L1 therapy. Our findings suggest that add-on VA correlates with improved survival in patients with advanced or metastasised NSCLC who were treated with PD-1/PD-L1 inhibitors irrespective of age, gender, tumour stage, or oncological treatment. The underlying mechanisms may include the synergistic modulation of the immune response. A limitation of this study is the observational non-randomised study design, which only allows limited conclusions to be drawn and prospective randomised trials are warranted.

Safety of Combined Targeted and Helixor®Viscum album L. Therapy in Breast and Gynecological Cancer Patients, a Real-World Data Study.

BACKGROUND: Newer personalized medicines including targeted therapies such as PARP inhibitors and CDK 4/6 inhibitors have been shown to improve the survival of breast and gynaecological cancer patients. However, efficacy outcomes may be ham5pered by treatment discontinuation due to targeted therapy-related adverse drug reactions or resistance. Studies have suggested that add-on mistletoe (Viscum album L., VA) improves the quality of life and ameliorates the cytotoxic side effects of standard oncological therapy in cancer patients. The primary objective of this real-world data study was to determine the safety profile of targeted therapy in combination with add-on Helixor® VA therapy compared to targeted therapy alone in breast and gynecological cancer patients. METHODS: The present study is a real-world data observational cohort study utilizing demographic and treatment data from the accredited national Network Oncology (NO) registry. The study has received ethics approval. The safety profile of targeted therapies with or without Helixor® VA therapy and safety-associated variables were evaluated by univariate and adjusted multivariable regression analyses. RESULTS: All stages of breast and gynecological cancer patients (n = 242) were on average 54.5 ± 14.2 years old. One hundred and sixty patients (66.1%) were in the control (CTRL, targeted therapy) and 82 patients (33.9%) were in the combinational (COMB, targeted plus Helixor® VA therapy) group. The addition of Helixor® VA did not hamper the safety profile (χ2 = 0.107, p-value = 0.99) of targeted therapy. Furthermore, no adverse events and a trend towards an improved targeted therapy adherence were observed in the COMB group. CONCLUSIONS: The present study is the first of its kind showing the applicability of Helixor® VA in combination with targeted therapies. The results indicate that add-on Helixor® VA does not negatively alter the safety profile of targeted therapies in breast and gynaecological cancer patients.

The essential oil compositions of three Sicilian accessions of Viscum album L. growing on three different host trees.

Viscum album L., (Common Mistletoe), is a hemiparasitic shrub that lives on a wide range of woody plant species, known since Neolithic period for its ritual and for pharmacological properties. Up to now, no investigation has been reported on the chemical composition of the essential oils of V. album aerial parts in relation with the diverse host trees. Consequently, the essential oils compositions of three Sicilian accession of V. album, growing on Quercus suber L., Crataegus monogyna Jacq. and Olea europaea L. var. europaea cv. 'Santagatese', respectively, were evaluated by GC-MS. The three populations showed quite different profiles indicating that the nature of the host considerably influences the chemical composition of the guest plant, V. album.

Phytochemical Profile and Antioxidant Capacity of Viscum album L. Subsp. album and Effects on Its Host Trees.

Viscum album L. subsp. album is a hemiparasitic plant that is recognized as a medicinal plant due to its beneficial effects, including anti-tumor activity, antioxidant, anti-inflammatory, anti-hepatotoxic, hypoglycemic, and antimicrobial properties as well as for lowering blood pressure. On the other hand, mistletoe is a biotic stressor for both deciduous trees and conifers. Our main aim was to evidence the influence of mistletoe on the content of chlorophylls, proline, total phenols, flavonoids, and antioxidant capacity of leaves from tree host trees (Malus domestica, Prunus domestica, and Populus alba) that grow on the northwest of Romania. In addition, HPLC-DAD-MS-ESI+ was used to analyze the phenolic acid and flavonoid profiles of V. album L. subsp. album leaves according to their parasitized hosts. A significant decrease in chlorophyll a level of approximately 32% was detected in poplars infested with mistletoe, followed by infested apples and plums with pigment reductions of 29.25% and 9.65%, respectively. The content of total phenols and flavonoids in the parasitized trees was higher compared to the non-parasitized ones. In the case of poplar, which presented the highest incidence of mistletoe infestation (70.37%), the content of total phenols in the leaves was two times higher compared to non-infested leaves. Based on HPLC chromatographic analysis, leaves of mistletoe growing on apple (VAM) had the highest content of phenolic acids (7.833 mg/g dw), followed by mistletoe leaves on poplar (VAO) and plum (VAP) (7.033 mg/g dw and, respectively, 5.559 mg/g dw). Among the flavonols, the predominant component was Rhamnazin glucosides in the amount of 1.025 ± 0.08 mg/g dw in VAO, followed by VAP and VAM (0.514 ± 0.04 and 0.478 ± 0.04 mg/g dw, respectively). Although our results show that mistletoe negatively influences the host trees, it is still a valuable plant that must be exploited to bring benefits to human health.

Phytochemical screening and effect of Viscum album L. on monoamine oxidase A and B activity and serotonin, dopamine and serotonin receptor 5-HTR1A levels in Galleria mellonealla (Lepidoptera).

ETHNOPHARMACOLOGICAL RELEVANCE: Viscum album L. (European mistletoe), a member of the Santalaceae, is a hemiparasitic, evergreen shrub growing on deciduous and coniferous trees. In traditional and folk medicine, mistletoe was used for the treatment of central nervous system disorders such as epilepsy, hysteria, insomnia, nervous excitability, neuralgia, headache, dizziness and fatigue. However, relatively little is known of its neuropharmacological activity. AIM OF THE STUDY: The aim of the present study was to evaluate the effect of treatment with aqueous and hydroethanolic extracts from Viscum album L. parasitizing birch, linden and pine, on MAO-A and MAO-B activity as well as serotonin, dopamine and serotonin receptor 5-HTR1A levels in Galleria mellonella (Lepidoptera) larvae. MATERIALS AND METHODS: The phytochemical composition of the extracts was characterised using UPLC-DAD-ESI-MS/MS. To investigate the neuropharmacological activity of Viscum album L. extracts, Galleria mellonella (Lepidoptera) larvae were used as a model organism. The inhibitory potential of the extracts against MAO-A and MAO-B was determined by fluorometry. The serotonin, dopamine and serotonin receptor 5-HTR1A levels in larvae hemolymph after treatment were quantified by ELISA. RESULTS: UPLC-DAD-ESI-MS/MS analysis allowed the identification of 88 compounds, either full or in part. Most of the characterised phytochemicals were flavonoids, hydroxycinnamic acids and lignans. Screening found that aqueous and hydroethanolic mistletoe extracts inhibited the enzymatic activity of either MAO-A or MAO-B or both. Additionally, mistletoe extract administration increased the levels of serotonin and serotonin receptor 5-HTR1A. None of the tested extracts had any significant effect on dopamine level. CONCLUSIONS: A key novel finding was that the aqueous and hydroethanolic extracts from Viscum album L. inhibited monoamine oxidase activity and increased the levels of serotonin and serotonin receptor 5-HTR1A in Galleria mellonella (Lepidoptera) larvae. These properties may be due to the presence of phenolic constituents, particularly flavonoids. Further research based on bioassay-guided fractionation of mistletoe is needed to identify CNS-active molecules.

Mistletoe Extract Targets the STAT3-FOXM1 Pathway to Induce Apoptosis and Inhibits Metastasis in Breast Cancer Cells.

Mistletoe extracts (Viscum album L.) have been widely used as complementary and alternative medicines for the treatment of cancer, and their cytotoxic effects have been reported on various types of cancer. However, the molecular targets of mistletoe extracts have not been well studied. Herein, we investigated molecules associated with the in vitro and in vivo anticancer effects of mistletoe extract using 4T1 murine breast cancer cells. Mistletoe extract induced apoptosis and inhibited the signal transducer and activator of transcription3 (STAT3) phosphorylation. This inhibition was accompanied by the downregulations of forkhead box M1 (FOXM1) and the DNA repair proteins, RAD51 and survivin. Mistletoe extract simultaneously increased the expression of the DNA damage marker proteins, phosphorylated H2A histone family member X (H2A.X), and phosphorylated p38. Furthermore, mistletoe extract effectively suppressed tumor growth in 4T1 tumor-bearing BALB/c mice. In addition to tumor growth inhibition, mistletoe extract inhibited lung metastasis in the tumor-bearing mice and cell invasiveness by downregulating the expressions of matrix metalloproteinases (MMPs), urokinase-type plasminogen activator (uPA), uPA receptor, and markers of epithelial-mesenchymal transition (snail and fibronectin). Taken together, our results suggest that mistletoe extract targets the STAT3-FOXM1 pathway for its cytotoxic effects, and that mistletoe extracts might be useful for the treatment of patients with cancers highly expressing the STAT3-FOXM1 pathway.

Overall Survival of Nonmetastasized NSCLC Patients Treated With Add-On Viscum album L: A Multicenter Real-World Study.

BACKGROUND: Recent data suggest a beneficial effect of add-on treatment with Viscum album L (VA) on the survival in cancer patients. The objective of this study was to compare the impact of standard oncological therapy plus add-on VA treatment (S+VA) versus standard oncological therapy alone (S) on the overall survival (OS) of patients with nonmetastasized non-small cell lung carcinoma (NSCLC). METHODS: The multicenter real-world data study was conducted using data from the Network Oncology Clinical Registry. The primary end point was OS. OS and impact on hazard in both treatment groups were compared. RESULTS: A total of 275 patients with stages I to IIIA NSCLC were enrolled (mean age = 67.6 years, 57.2% male patients). No significant difference of OS was observed between both groups. Even though not significant, for a subgroup of unresected patients with stage I NSCLC, adenocarcinoma or squamous cell carcinoma, a medium effect size OS improvement was observed for S+VA compared to S. CONCLUSIONS: Our findings support the importance of surgery as the most effective intervention in nonmetastasized NSCLC patients. Add-on VA therapy shows here no additional effect in resected patients. However, a small subgroup analysis suggests a possible role of add-on VA for nonresected subgroups. Our results complement existing knowledge on the clinical impact of add-on VA therapy in NSCLC patients and may serve as hypothesis-generating data for further examinations in this cohort. Further research could be directed towards the role of combined therapy for nonresected early-stage NSCLC.

Phytochemical analysis and in vitro anti-proliferative activity of Viscum album ethanolic extracts.

BACKGROUND: Viscum album L. (Santalaceae), commonly known as mistletoe, is a hemiparasitic plant traditionally used in complementary cancer treatment. Its antitumor potential is mostly attributed to the presence of aqueous soluble metabolites; however, the use of ethanol as solvent also permits the extraction of pharmacological compounds with antitumor potential. The clinical efficacy of mistletoe therapy inspired the present work, which focuses on ethanolic extracts (V. album "mother tinctures", MT) prepared from different host trees. METHODS: Samples from three European subspecies (album, austriacum, and abietis) were harvested, and five different V. album-MT strains were prepared. The following phytochemical analyses were performed: thin layer chromatography (TLC), high-performance liquid chromatography (HPLC) and liquid chromatography-high resolution mass spectrometry (LC-HRMS). The proliferation assay was performed with WST-1 after incubation of tumor (Yoshida and Molt-4) and fibroblast cell lines (NIH/3 T3) with different MT concentrations (0.5 to 0.05% v/v). The cell death mechanism was investigated by flow cytometry (FACS) using Annexin V-7AAD. RESULTS: Chemical analyses of MT showed the presence of phenolic acids, flavonoids and lignans. The MT flavonoid and viscotoxin contents (mg/g fresh weight) were highest in Quercus robur (9.67 ± 0.85 mg/g) and Malus domestica (3.95 ± 0.58 mg/mg), respectively. The viscotoxin isoform proportions (% total) were also different among the VA subspecies with a higher content of A3 in V. album growing on Abies alba (60.57 ± 2.13). The phytochemical compounds as well as the viscotoxin contents are probably related to the antitumor effects of MT. The cell death mechanisms evaluated by colorimetric and FACS methodologies involved necrotic damage, which was host tree-, time- and dose- dependent, with different selectivity to tumor cells. Mother tincture from V. album ssp. abietis was the most effective at inducing in vitro cellular effects, even when incubated at the smallest concentration tested, probably because of the higher content of VT A3. CONCLUSION: Our results indicate the promising antitumor potential of Viscum album ethanolic extracts and the importance of botanical and phytochemical characterization for in vitro anti-proliferative effects.

Ecological and Landscape Factors Affecting the Spread of European Mistletoe (Viscum album L.) in Urban Areas (A Case Study of the Kaliningrad City, Russia).

Green spaces are very important for an urban environment. Trees in cities develop under more stressful conditions and are, therefore, more susceptible to parasite including mistletoe infestation. The aim of this study was to investigate the ecological, microclimatic, and landscape factors causing the spread of European mistletoe (Viscum album L.) in urban conditions. The most numerous hosts of mistletoe were Tilia cordata (24.4%), Acer platanoides (22.7%), and Populus nigra (16.7%). On average, there were more than 10 mistletoe bushes per tree. The mass mistletoe infestations (more than 50 bushes per the tree) were detected for Populus × berolinensis, Populus nigra, and Acer saccharinum. The largest number of infected trees was detected in the green zone (city parks), historical housing estates, and green zone along water bodies. Based on the results of principal component analysis (PCA), the main factors causing the spread of mistletoe on the urban territories are trees' age and relative air humidity. The factors reflecting environmental pollution (the content of heavy metals in the soil and the concentration of nitrogen dioxide in the air) did not statistically affect the mistletoe distribution in the study area. However, this result may be due to the heterogeneity of other parameters in the studied areas. Therefore, additional research is required to more accurately interpret the data on the relationship between environmental pollutions and distribution of mistletoe infestation of trees in urban areas.

[Mistletoe in the treatment of cancer patients]. / Die Misteltherapie in der Behandlung von Patienten mit einer Krebserkrankung.

Mistletoe (Viscum album L.) continues to be the medical herb prescribed most frequently for cancer patients in German-speaking countries. Demand for this therapy often comes from patients themselves and requires careful consideration by the attending physician during consultation.In German-speaking countries, mistletoe extracts are available as approved drugs (based on monographs of the commissions C and E of the German Federal Institute for Drugs and Medical Devices). In Switzerland, treatment costs are generally covered by statutory health insurance. In Germany, coverage is limited to palliative care. In adjuvant cases, treating physicians can request coverage by the health insurance if patients suffer from side effects due to the antitumoral treatment.The spectrum of Viscum album extract includes mistletoe lectin I; II, and III, viscotoxins, flavonoids, amino acids, polysaccharides, and membrane lipids. Preclinical studies have demonstrated cytotoxic, apoptosis-inducing, and immunomodulatory effects.Many clinical studies indicate a supportive efficacy of mistletoe extracts in tumor patients, even though methodological quality is discussed controversially in many cases. Clinical data regarding effects on survival of patients is inconsistent; effects concerning quality of life as well as the tolerability of antitumoral treatments are evaluated more positively.In view of the high demand on the patient side and increasing scientific evidence, the general conditions for prescriptions should continue as well as the ongoing scientific evaluation.

Absence of herb-drug interactions of mistletoe with the tamoxifen metabolite (E/Z)-endoxifen and cytochrome P450 3A4/5 and 2D6 in vitro.

BACKGROUND: Women diagnosed with breast cancer frequently seek complementary and alternative (CAM) treatment options that can help to cope with their disease and the side effects of conventional cancer therapy. Especially in Europe, breast cancer patients use herbal products containing mistletoe (Viscum album L.). The oldest and one of the most prescribed conventional drugs for the treatment of estrogen receptor positive breast cancer is tamoxifen. Aside from positive clinical experience with the combination of tamoxifen and mistletoe, little is known about possible herb-drug interactions (HDIs) between the two products. In the present in vitro study, we investigated the effect of standardized commercial mistletoe preparations on the activity of endoxifen, the major active metabolite of tamoxifen. METHODS: The estrogen receptor positive human breast carcinoma cell line MCF-7 was treated with (E/Z)-endoxifen hydrochloride in the presence and absence of a defined estradiol concentration. Each concentration of the drug was combined with fermented Viscum album L. extracts (VAE) at clinically relevant doses, and proliferation, apoptosis and cell cycle were analyzed. In parallel, possible inhibition of CYP3A4/5 and CYP2D6 was investigated using 50-donor mixed gender pooled human liver microsomes (HLMs). RESULTS: VAE did not inhibit endoxifen induced cytostasis and cytotoxicity. At higher concentrations, VAE showed an additive inhibitory effect. VAE preparations did not cause inhibition of CYP3A4/5 and CYP2D6 catalyzed tamoxifen metabolism. CONCLUSIONS: The in vitro results suggest that mistletoe preparations can be used in combination with tamoxifen without the risk of HDIs.

Clinical Safety of Combined Targeted and Viscum album L. Therapy in Oncological Patients.

Background: Despite improvement of tumor response rates, targeted therapy may induce toxicities in cancer patients. Recent studies indicate amelioration of adverse events (AEs) by add-on mistletoe (Viscum album L., VA) in standard oncological treatment. The primary objective of this multicenter observational study was to determine the safety profile of targeted and add-on VA therapy compared to targeted therapy alone. Methods: Demographic and medical data were retrieved from the Network Oncology registry. Allocation to either control (targeted therapy) or combinational group (targeted/add-on VA) was performed. Safety-associated variables were evaluated by adjusted multivariable analyses. Results: The median age of the study population (n = 310) at first diagnosis was 59 years; 67.4% were female. In total, 126 patients (40.6%) were in the control and 184 patients (59.4%) in the combination group. Significant differences were observed between both groups with respect to overall AE frequency (χ² = 4.1, p = 0.04) and to discontinuation of standard oncological treatment (χ² = 4.8, p = 0.03) with lower rates in the combinational group (20.1%, 35% respectively) compared to control (30.2%, 60.5%, respectively). Addition of VA to targeted therapy significantly reduced the probability of oncological treatment discontinuation by 70% (Odds ratio (OR) 0.30, p = 0.02). Conclusions: Our results indicate a highly significant reduction of AE-induced treatment discontinuation in all-stage cancer patients when treated with VA in addition to targeted therapy.

Crystal Structure of Mistletoe Lectin I (ML-I) from Viscum album in Complex with 4-N-Furfurylcytosine at 2.85 Å Resolution.

BACKGROUND: Viscum album (the European mistletoe) is a semi-parasitic plant, which is of high medical interest. It is widely found in Europe, Asia, and North America. It contains at least three distinct lectins (i.e. ML-I, II, and III), varying in molecular mass and specificity. Among them, ML-I is in focus of medical research for various activities, including anti-cancer activities. To understand the molecular basis for such medical applications, a few studies have already addressed the structural and functional analysis of ML-I in complex with ligands. In continuation of these efforts, we are reporting the crystal structure of ML from Viscum album in complex with the nucleic acid oxidation product 4-N-furfurylcytosine (FC) refined to 2.85 Å resolution. FC is known to be involved in different metabolic pathways related to oxidative stress and DNA modification. METHODS: X-ray suitable hexagonal crystals of the ML-I/FC complex were grown within four days at 294 K using the hanging drop vapor diffusion method. Diffraction data were collected up to a resolution of 2.85 Å. The ligand affinity was verified by in-silico docking. RESULTS: The high-resolution structure was refined subsequently to analyze particularly the active site conformation and a binding epitope of 4-N-furfurylcytosine. A distinct 2Fo-Fc electron density at the active site was interpreted as a single FC molecule. The specific binding of FC is achieved also through hydrophobic interactions involving Tyr76A, Tyr115A, Glu165A, and Leu157A of the ML-I A-chain. The binding energy of FC to the active site of ML-I was calculated as well to be -6.03 kcal mol-1. CONCLUSION: In comparison to other reported ML-I complexes, we observed distinct differences in the vicinity of the nucleic acid base binding site upon interaction with FC. Therefore, data obtained will provide new insights in understanding the specificity, inhibition, and cytotoxicity of the ML-I A-chain, and related RIPs.

The Stability of Medicinal Plant microRNAs in the Herb Preparation Process.

Herbal medicine is now globally accepted as a valid alternative system of pharmaceutical therapies. Various studies around the world have been initiated to develop scientific evidence-based herbal therapies. Recently, the therapeutic potential of medicinal plant derived miRNAs has attracted great attraction. MicroRNAs have been indicated as new bioactive ingredients in medicinal plants. However, the stability of miRNAs during the herbal preparation process and their bioavailability in humans remain unclear. Viscum album L. (European mistletoe) has been widely used in folk medicine for the treatment of cancer and cardiovascular diseases. Our previous study has indicated the therapeutic potential of mistletoe miRNAs by using bioinformatics tools. To evaluate the stability of these miRNAs, various mistletoe extracts that mimic the clinical medicinal use as well as traditional folk medicinal use were prepared. The mistletoe miRNAs including miR166a-3p, miR159a, miR831-5p, val-miR218 and val-miR11 were quantified by stem-loop qRT-PCR. As a result, miRNAs were detectable in the majority of the extracts, indicating that consumption of medicinal plant preparations might introduce miRNAs into mammals. The factors that might cause miRNA degradation include ultrasonic treatment, extreme heat, especially RNase treatment, while to be associated with plant molecules (e.g., proteins, exosomes) might be an efficient way to protect miRNAs against degradation. Our study confirmed the stability of plant derived miRNAs during herb preparations, suggesting the possibility of functionally intact medicinal plant miRNAs in mammals.

Safety of Combined Treatment With Monoclonal Antibodies and Viscum album L Preparations.

Combination strategies involving chemotherapy and monoclonal antibodies (mAb) are commonly used in attempts to produce better clinical outcomes. This practice has led to new and ongoing toxicities that may lead to reductions in dose or noncompliance, limiting the effectiveness of treatment. Viscum album L (VA) preparations are widely used in Europe as additive therapy and have been associated with reduced chemotherapy-related adverse reactions and increased health-related quality of life. Concomitant VA therapy might also reduce toxicity related to mAb. This retrospective study investigated the safety of combined treatment with VA and mAb in cancer patients. A total of 43 patients had combined therapy (474 exposures); 12 had VA without mAb (129 exposures), and 8 had mAb without VA (68 exposures). Most patients (89.3%) received concomitant chemotherapy or supportive therapies. A total of 34 patients (60.7%) experienced 142 adverse events (AEs). Leucopenia (14.1% of all events), acneiform rash (8.5%), and stomatitis (6.3%) occurred most frequently. Longitudinal logistic regression analysis suggested a nearly 5 times higher odds of experiencing an AE following treatment with mAb compared with mAb plus VA (95% CI = 1.53-16.14). Our results, together with theoretical consideration of potential botanical-drug interactions, suggest that combined treatment with VA and mAb is safe.

Clinical safety of combined therapy of immune checkpoint inhibitors and Viscum album L. therapy in patients with advanced or metastatic cancer.

BACKGROUND: Despite improvement of tumour response rates in patients with progressive and metastatic cancer, immune checkpoint inhibitors (ICM) induce toxicities in cancer patients. Viscum album L. (VA, mistletoe) extracts are applied as add-on cancer therapy especially in German speaking countries and within integrative and anthroposophical concepts with the goal to improve quality of life. The primary objective of this pilot observational cohort study was to determine the rate of adverse events (AE) related to ICM therapy with and without VA in patients with advanced or metastatic cancer in a certified Cancer Center. METHODS: ICM or combined ICM/VA therapies were applied in patients with progressive or metastatic cancer. AE rates of both therapy groups were compared. RESULTS: A total of sixteen cancer patients were treated with ICM: nivolumab (75%), ipilimumab (19%) or pembrolizumab (6%). The median age of the study population was 64 years (IQR 57.8; 69.3); 44% were male. Of the sixteen patients receiving ICM, nine patients received additional VA (56%; ICM/VA group) and seven did not (44%; ICM group). No statistically significant differences were seen between groups with respect to AE-rates (67% ICM/VA versus 71% ICM). Adjusted multivariate regression analysis revealed that concomitant application of VA did not alter the AE rate in ICM treated patients. 85% of AEs were expected ICM reactions. No AEs of grade 3 or greater were documented for the total study cohort. CONCLUSIONS: This is the first study evaluating the clinical safety profile of ICM in combination with VA in patients with advanced or metastatic cancer. The overall AE rate of the study cohort is comparable to AE rates of ICM treatment in the literature. Our data indicate a first impression that concomitant VA application may not alter ICM-induced AE rates. However, the nature of this study does not allow excluding possible immunological interactions between ICM and VA. Further prospective trials in larger study cohorts should focus on the assessment of safety aspects, clinical efficacy and health related quality of life in patients with combined ICM/VA therapy. TRIAL REGISTRATION: DRKS00013335 , retrospectively registered (November 27th, 2017) at the German Clinical Trials Register ( www.drks.de ).

Immune-related and adverse drug reactions to low versus high initial doses of Viscum album L. in cancer patients.

BACKGROUND: Immune-related adverse drug reactions (ADRs) to immunotherapy agents have been associated with beneficial clinical outcomes in oncology. Viscum album L. (VA, European mistletoe) is frequently used as an immunomodulatory agent alongside conventional cancer treatment in Europe. VA has been associated with improved quality of life and a reduction in chemotherapy-related ADRs. Beneficial effects of VA are believed to be related to its immunomodulatory properties. Current guidelines recommend commencing with a low dose and increasing slowly overtime, however, off-label prescribing of high initial doses is common. PURPOSE: We investigated ADR profiles related to subcutaneous VA therapy commencing with low, recommended doses versus higher than recommended doses. STUDY DESIGN: Retrospective cohort study. METHODS: Medical records of 1361 cancer patients treated between 2003 and 2013 were assessed. Patients were divided into two groups based on whether the dose of their first VA injection adhered to current guidelines. Patient characteristics and suspected VA-related ADRs were compared between dose groups. RESULTS: Of 1361 cancer patients, 516 (38%) started with a recommended, low dose of VA(≤0.02 mg) and 845 (62%) started with a higher dose(>0.02 mg). Groups did not differ by age or gender, but significant differences were observed for type (p < 0.001) and stage of cancer (p = 0.05). Starting with a high dose of VA was significantly associated with a higher incidence of VA-related ADRs compared to starting with a low dose (20.7% versus 0.8%, p < 0.001). Adjusting for age, gender, tumour type and stage of disease, produced an odds ratio of 37.5 (95% CI = 15.7-122.8, p < .001). Almost all ADRs, irrespective of the initial VA dose, were of mild or moderate intensity. Most ADRs were immune-related, general disorders and administration site conditions, many of which are desired reactions, such as pyrexia and local reactions. Overall, no serious ADRs occurred. CONCLUSIONS: Starting VA therapy with a higher than recommended dose was associated with a high frequency of ADRs, however, nearly all ADRs were expected, of mild to moderate intensity and most were desired reactions. Future research is necessary to investigate whether higher incidences of immune-related events are indicators of beneficial immunomodulation and better clinical outcomes.

LC-ESI-MS/MS Identification of Biologically Active Phenolic Compounds in Mistletoe Berry Extracts from Different Host Trees.

A new, rapid, sensitive and selective liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method was developed to determine the content of flavonoid aglycones and phenolic acids in mistletoe berries (Viscum album L.) harvested from six different Polish host trees. Additionally, the total phenolic content (TPC) and total flavonoid content (TFC) as well as an antioxidant and antiproliferative activity were evaluated for the first time. The plant material was selectively extracted using ultrasound assisted maceration with methanol/water (8:2) solution. The obtained TPC and TFC results varied from 7.146 to 9.345 mg GA g-¹ and from 1.888 to 2.888 mg Q g-1 of dry extracts, respectively. The LC-ESI-MS/MS analysis demonstrated the highest content of phenolic acids in mistletoe berries from Populus nigra 'Italica' L. and flavonoid aglycones in mistletoe berries from Tilia cordata Mill. (354.45 µg and 5.955 µg per g dry extract, respectively). The moderate antioxidant activity of investigated extracts was obtained. The studies revealed that the examined extracts decreased the proliferation of human colon adenocarcinoma cells line LS180 in a dose-dependent manner without cytotoxicity in the human colon epithelial cell line CCD 841 CoTr. Moreover, the obtained results suggest considerable impact of polyphenols on the anticancer activity of these extracts.

ViscumTT induces apoptosis and alters IAP expression in osteosarcoma in vitro and has synergistic action when combined with different chemotherapeutic drugs.

BACKGROUND: Osteosarcoma is the most common bone tumor and is associated with a poor prognosis. Conventional therapies, surgery and chemotherapy, are still the standard but soon reach their limits. New therapeutic approaches are therefore needed. Conventional aqueous mistletoe extracts from the European mistletoe (Viscum album L.) are used in complementary cancer treatment. These commercial extracts are water-based and do not include water-insoluble compounds such as triterpenic acids. However, both hydrophilic and hydrophobic triterpenic acids possess anti-cancer properties. In this study, a whole mistletoe extract viscumTT re-created by combining an aqueous extract (viscum) and a triterpene extract (TT) was tested for its anti-cancer potential in osteosarcoma. METHODS: Two osteosarcoma cell lines were treated with three different mistletoe extracts viscum, TT and viscumTT to compare their apoptotic potential. For this purpose, annexin/PI staining and caspase-3, -8 and -9 activity were investigated by flow cytometry. To determine the mechanism of action, alterations in expression of inhibitors of apoptosis (IAPs) were detected by western blot. Apoptosis induction by co-treatment of viscum, TT and viscumTT with doxorubicin, etoposide and ifosfamide was examined by flow cytometry. RESULTS: In vitro as well as ex vivo, the whole mistletoe extract viscumTT led to strong inhibition of proliferation and synergistic apoptosis induction in osteosarcoma cells. In the investigations of mechanism of action, inhibitors of apoptosis such as XIAP, BIRC5 and CLSPN showed a clear down-regulation after viscumTT treatment. In addition, co-treatment with doxorubicin, etoposide and ifosfamide further enhanced apoptosis induction, also synergistically. CONCLUSION: ViscumTT treatment results in synergistic apoptosis induction in osteosarcoma cells in vitro and ex vivo. Additionally, conventional standard chemotherapeutic drugs such as doxorubicin, etoposide and ifosfamide were able to dramatically enhance apoptosis induction. These results promise a high potential of viscumTT as an additional adjuvant therapy approach for osteosarcoma.

Interaction of a standardized mistletoe (Viscum album) preparation with antitumor effects of Trastuzumab in vitro.

BACKGROUND: Besides conventional anticancer therapy many breast cancer patients use complementary and alternative medicine (CAM) like the medicinal herb mistletoe (Viscum album L.). To gain more knowledge about possible herb-drug interactions between CAM and conventional anticancer medications, in the present in vitro study we investigated the effect of a standardized mistletoe preparation on the action of Trastuzumab, a drug used for the treatment of Her-2 positive breast cancer. METHODS: The Her-2 positive human breast carcinoma cell line SK-BR-3 was treated with Trastuzumab. Different doses of the drug were combined with Viscum album extract (VAE) in clinically relevant doses. Proliferation, apoptosis, cell cycle and the secretion of vascular endothelial growth factor (VEGF) were analyzed. RESULTS: No inhibition of antitumor efficacy of Trastuzumab by VAE was detected. VAE and Trastuzumab, either alone or in combination, inhibited proliferation of SK-BR-3 cells in vitro. At higher concentrations VAE induced apoptosis, which was not observed for Trastuzumab. Cells treated with Trastuzumab underwent a G0/G1 cell cycle arrest and cells treated with VAE a G2/M arrest. After application of the two drugs in combination both G0/G1 and G2/M arrest was observed. VEGF secretion of SK-BR-3 cells was significantly inhibited by sole treatment with Trastuzumab or VAE. Combined treatment of Trastuzumab and VAE at clinically relevant doses showed additive inhibitory effects on VEGF secretion. CONCLUSIONS: VAE did not interfere with cytostatic effects of Trastuzumab on SK-BR-3 cells in vitro. Our in vitro results suggest that no risk of safety by herb drug interactions has to be expected from the exposition of cancer cells to Trastuzumab and VAE simultaneously. In contrast, VAE and Trastuzumab seem to exhibit complementary anti-cancer effects in vitro.