Dicoumarol, an NQO1 inhibitor, blocks cccDNA transcription by promoting degradation of HBx.

BACKGROUND & AIMS: Current antiviral therapies help keep HBV under control, but they are not curative, as they are unable to eliminate the intracellular viral replication intermediate termed covalently closed circular DNA (cccDNA). Therefore, there remains an urgent need to develop strategies to cure CHB. Functional silencing of cccDNA is a crucial curative strategy that may be achieved by targeting the viral protein HBx. METHODS: We screened 2,000 small-molecule compounds for their ability to inhibit HiBiT-tagged HBx (HiBiT-HBx) expression by using a HiBiT lytic detection system. The antiviral activity of a candidate compound and underlying mechanism of its effect on cccDNA transcription were evaluated in HBV-infected cells and a humanised liver mouse model. RESULTS: Dicoumarol, an inhibitor of NAD(P)H:quinone oxidoreductase 1 (NQO1), significantly reduced HBx expression. Moreover, dicoumarol showed potent antiviral activity against HBV RNAs, HBV DNA, HBsAg and HBc protein in HBV-infected cells and a humanised liver mouse model. Mechanistic studies demonstrated that endogenous NQO1 binds to and protects HBx protein from 20S proteasome-mediated degradation. NQO1 knockdown or dicoumarol treatment significantly reduced the recruitment of HBx to cccDNA and inhibited the transcriptional activity of cccDNA, which was associated with the establishment of a repressive chromatin state. The absence of HBx markedly blocked the antiviral effect induced by NQO1 knockdown or dicoumarol treatment in HBV-infected cells. CONCLUSIONS: Herein, we report on a novel small molecule that targets HBx to combat chronic HBV infection; we also reveal that NQO1 has a role in HBV replication through the regulation of HBx protein stability. LAY SUMMARY: Current antiviral therapies for hepatitis B are not curative because of their inability to eliminate covalently closed circular DNA (cccDNA), which persists in the nuclei of infected cells. HBV X (HBx) protein has an important role in regulating cccDNA transcription. Thus, targeting HBx to silence cccDNA transcription could be an important curative strategy. We identified that the small molecule dicoumarol could block cccDNA transcription by promoting HBx degradation; this is a promising therapeutic strategy for the treatment of chronic hepatitis B.

Safety of Direct Oral Anticoagulants and Vitamin K Antagonists in Oldest Old Patients: A Prospective Study.

OBJECTIVE: The safety of direct oral anticoagulants (DOACs) in oldest old patients with nonvalvular atrial fibrillation (NVAF) in daily clinical practice has not been systematically assessed. This study examined the safety of DOACs and dicumarol (a vitamin K antagonist) in NVAF geriatric patients. DESIGN: Prospective study from January 2010 through June 2015, with follow-up through January 2016. SETTING: Geriatric medicine department at a tertiary hospital. PARTICIPANTS: A total of 554 outpatients, 75 years or older, diagnosed of NVAF and starting oral anticoagulation. MEASUREMENTS: The main outcome was bleeding, which was classified into major (including those life-threatening) and nonmajor episodes. Statistical analyses were performed with Cox regression. RESULTS: A total of 351 patients received DOACs and 193 dicumarol. Patients on DOACs were older, with more frequent comorbidities, mobility limitation and disability in activities of daily living, as well as higher mortality, than those treated with dicumarol. The incidence of any bleeding was 19.2/100 person-years among patients on DOACs and 13.7/100 person-years on dicumarol; corresponding figures for major bleeding were 5.2 for those on DOACs, and 3.3 for those on dicumarol. In crude analyses, hazard ratios (95% confidence intervals) for any bleeding, and for mayor bleeding in patients on DOACs vs dicumarol were 1.60 (1.04-2.44) and 2.22 (0.88-5.59), respectively. Excess risk of bleeding associated with DOACs vs dicumarol disappeared after adjustment for clinical characteristics, so that corresponding figures were 1.19 (0.68-2.08) and 1.01 (0.35-2.93). Results did not vary across subgroups of high-risk patients. CONCLUSION: In very old patients with NVAF, the higher risk of bleeding associated with DOACs vs dicumarol could be mostly explained by the worse clinical profile of patients receiving DOACs. Risk of bleeding was rather high, and warrants close clinical monitoring.

Periodontal and biochemical bone metabolism assessment on a chronic oral anticoagulation population treated with dicoumarins.

BACKGROUND: The aim is to evaluate periodontal alteration and biochemical markers associated with bone turnover in chronic oral with dicoumarins anticoagulant treatment patients. MATERIAL AND METHODS: 80 patients treated with oral anticoagulants were divided into 2 cohort: Group A (n=36) 6 month to 1 year with anticoagulant treatment and Group B (n=44) > 2 years with anticoagulant treatment. Clinical evaluation included: Clinical attachment level (CAL), plaque index (PI) and gingival index (GI). Analytically biochemical parameters of bone remodeling (calcium and phosphorus), formation (total acid phosphatase, alkaline phosphatase and osteocalcin) and resorption (tartrate-resistant acid phosphatase and beta-crosslaps) were evaluated. RESULTS: High values of PI (67-100%) especially in men and in Group B were observed. Men with anticoagulation treatment length showed an increased GI (49.167 vs 78.083) while Group B women showed a decreased GI in comparison with Group A (59.389 vs 42.120). Women presented a greater average CAL than men as well as Group B vs Group A but without statistical significance. All biochemical markers were decreased respect to values of general population. Osteocalcin in GroupB women showed a statistically significant outcome vs GroupA (p=0.004). Acid phosphatase (total and tartrate-resistant) has a slight increase in Group B women versus Group A, and Beta-crosslap showed lower values in Group A men than Group B and slightly lower in Group A women versus Group B, without statistical significance. CONCLUSIONS: Patients showed a slight to moderate degree of periodontal affectation, especially gingivitis related to bacterial plaque. Periodontal disorders tended to be more severe in Group B. While bone remodeling showed an overall decrease with greater affectation of bone neoformation phenomena, bone destruction tended to recover and normalize in time.

Can dicoumarol be used as a gonad-safe anticancer agent: an in vitro and in vivo experimental study.

STUDY HYPOTHESIS: Dicoumarol (DC) has potential for use as a gonad-safe anticancer agent. STUDY FINDING: DC altered cell proliferation, decreased viability and increased apoptosis in Vero and MCF-7 cell lines but did not show any toxic effect on mouse ovarian tissues and developing oocytes in vitro and in vivo. WHAT IS KNOWN ALREADY: DC suppresses cell proliferation and increases apoptosis in various cancer cells such as breast, urogenital and melanoma. DC has also been reported to alter the anticancer effects of several chemotherapeutics, including cisplatin, gemcitabine and doxorubicin in prostate, liver and uroepithelial cancer cells, respectively. STUDY DESIGN, SAMPLES/MATERIALS, METHODS: Vero (African green monkey kidney epithelial cells) and MCF-7 (human cancerous breast epithelial cells) cell lines and mouse granulosa cells isolated from 21-day-old female BALB/c mice (n = 21) were used to assess the effects of DC (10, 50, 100 and 200 µm) for 24 and 48 h on cell proliferation, viability and apoptotic cell death. In vivo experiments were performed with a single i.p. injection of 32 mg/kg DC in 21-day-old female BALB/c mice (n = 12). Following 48 h, animals were sacrificed by cervical dislocation and histological sections of isolated ovaries were evaluated for apoptosis. Viability assays were based on the trypan blue dye exclusion method and an automated cell counter device was used. Terminal deoxynucleotidyltransferase-mediated dUTP nick-end labelling (TUNEL) and Annexin-V immunofluorescence were assessed by 3D confocal microscopy to address apoptotic cell death. We also assessed whether DC inhibits cell proliferation and viability through NQO1 [NAD(P)H Quinone Oxidoreductase 1], an intracellular inhibitor of reactive oxygen species (ROS). The meiotic spindle and chromosomes were studied in mouse oocytes by α-ß-tubulin and 7-aminoactinomycine D (7-AAD) immunostaining in vitro and in vivo. MAIN RESULTS AND THE ROLE OF CHANCE: DC does not block oocyte maturation and no significant alteration was noted in meiotic spindle or chromosome morphology in metaphase-II (M-II) stage oocytes following DC treatment in vitro or in vivo. In contrast, exposure to DC for 24 h suppressed cell proliferation (P = 0.026 at 200 µm), decreased viability (P = 0.002 at 200 µm) and increased apoptosis (P = 0.048 at 100 µm) in Vero and MCF-7 cell lines, compared with controls. These changes were not related to intracellular NQO1 levels. Mouse granulosa cells were unaffected by 50 or 100 µm DC treatment for 24 and 48 h in vitro. DC treatment in vivo did not alter the number of primordial follicles or the ratio of apoptosis in primordial, primary and secondary follicles, as well as in antral follicles, compared with the controls. LIMITATIONS, REASONS FOR CAUTION: DC was tested for ovarian toxicity only in isolated mouse oocytes/ovaries and healthy BALB/c mice. No cancer formation was used as an in vivo test model. The possibility that DC may potentiate ovarian toxicity when combined with traditional chemotherapeutic agents, such as mitomycin-C, cisplatin, gemcitabine and doxorubicin, must be taken into account, as DC is known to alter their effects in some cancer cells. WIDER IMPLICATIONS OF THE FINDINGS: The present study evaluated, for the first time, the effect of DC on ovarian tissue. The results suggested that DC is not toxic to ovarian tissues and developing oocytes; therefore, DC should be assessed further as a potential anticancer agent when female fertility preservation is a concern. LARGE SCALE DATA: N/A. STUDY FUNDING AND COMPETING INTERESTS: This work includes data from dissertation thesis entitled 'Effects of dicoumarol on mitotic and meiotic cells as an anticancer agent' by DA, 2014 and was partly supported by The National Scientific and Technological Research Council of Turkey (SBAG-109S415) to AC, OC and SO. The authors confirm that this article content presents no conflicts of interest.

Depleting Tumor-NQO1 Potentiates Anoikis and Inhibits Growth of NSCLC.

UNLABELLED: The fundamental role that NAD(P)H/quinone oxidoreductase 1 (NQO1) plays, in normal cells, as a cytoprotective enzyme guarding against stress induced by reactive oxygen species (ROS) is well documented. However, what is not known is whether the observed overexpression of NQO1 in neoplastic cells contributes to their survival. The current study discovered that depleting NQO1 expression in A549 and H292 lung adenocarcinoma cells caused an increase in ROS formation, inhibited anchorage-independent growth, increased anoikis sensitization, and decreased three-dimensional tumor spheroid invasion. These in vivo data further implicate tumor-NQO1 expression in a protumor survival role, because its depletion suppressed cell proliferation and decreased lung tumor xenograft growth. Finally, these data reveal an exploitable link between tumor-NQO1 expression and the survival of lung tumors because NQO1 depletion significantly decreased the percentage of ALDH((high)) cancer cells within the tumor population. IMPLICATIONS: Loss of tumor-NQO1 expression inhibits tumor growth and suggests that novel therapeutics directed at tumor-NQO1 may have clinical benefit.

Nuevos anticoagulantes frente a anticoagulantes clásicos: ventajas e inconvenientes / New versus classical anticoagulants: advantages and disadvantages

El descubrimiento de los anticoagulantes se inició en 1916 con la aparición de la heparina, en 1941 se aisló y caracterizo el 3,3’-metilenobis-(4-hidroxicumarina), que más tarde se conocería como dicumarol o bishidroxicumarina. El desarrollo de los nuevos anticoagulantes orales ha sido lento hasta la reciente introducción de dabigatrán, un inhibidor oral de trombina, y rivaroxabán, inhibidor oral del factor Xa. La heparina presenta una serie de inconvenientes, como la necesidad de administración parenteral, complicaciones hemorrágicas al inducir trombocitopenia, osteoporosis, reacciones cutáneas, reacciones de hipersensibilidad y elevación de las transaminasas. Los antagonistas de la vitamina K tienen un mecanismo de acción indirecto, presentan múltiples interacciones con fármacos y alimentos, dificultad de dosificación y precisan la monitorización de su efecto. Las limitaciones de los actuales fármacos antitrombóticos ha impulsado la búsqueda de nuevos agentes, que para superar las limitaciones de los AVK deben reunir, entre otras, las siguientes características: administración oral, bajo riesgo de hemorragia, una cinética predecible, que no requieran vigilancia de la coagulación, que no sea necesario ajustar la dosis y tener una baja interacción con fármacos y alimentos (AU)

The discovery of anticoagulants started in 1916 with the finding of heparin; in 1941 3,3’-metilenobis-(4-hidroxicumarin) was isolated and characterized, and would later become known as dicumarol or bishydroxycoumarin. The development of the new oral anticoagulants was slow until the recent introduction of dabigatran, a novel oral thrombin inhibitor, and rivaroxaban, an oral factor Xa (FXa) inhibitor-Heparin has a series of disadvantages, such as the need for parenteral administration, hemorrhagic complications if thrombocytopenia develops, osteoporosis, cutaneous reactions, hypersensitivity reactions, and transaminase elevation. In addition, monitoring is required. Vitamin K antagonists also require monitoring and have an indirect mechanism of action and multiple food and drug interactions. Dosing is also problematic. The limitations of currently available antithrombotic agents have prompted the search for new drugs. To overcome the limitations of VKA, these drugs should include the following characteristics, among others; oral administration, low bleeding risk, predictable kinetics, few food and drug interactions and no requirement for dose adjustments. (AU)

Dicoumarol enhances doxorubicin-induced cytotoxicity in p53 wild-type urothelial cancer cells through p38 activation.

OBJECTIVE: To investigate the effectiveness of a combined treatment of 3-30-methylene-bis[4-hydroxycoumarin] (dicoumarol) with doxorubicin for the treatment of urothelial cancer, as doxorubicin is a common chemotherapeutic agent but its therapeutic efficacy is limited. MATERIALS AND METHODS: The synergistic effect of dicoumarol with chemotherapeutic agents such as cisplatin, doxorubicin and paclitaxel was evaluated in RT112 urothelial cancer cells. Then, dicoumarol-mediated enhancement of doxorubicin-induced cytotoxicity was screened in urothelial cancer cell lines with different p53 statuses or RT112 stable transfectants with a dominant-negative mutant of p53 (p53DN). To clarify the importance of the modification of p53 function by dicoumarol to enhance doxorubicin toxicity, the change in the p53-p21 pathway and mitogen-activated protein kinase (MAPK)-mitochondria pathway by the combined treatment were elucidated by Western blot analysis. Finally, the effect of p21 knockdown in the susceptibility to doxorubicin was examined with RT112 stable transfectants with short hairpin RNA (shRNA) of p21. RESULTS: Dicoumarol significantly increased the susceptibility of RT112 cells to cisplatin and doxorubicin, but not to paclitaxel in RT112 cells. Dicoumarol (100 microm) also enhanced the cytotoxicity of doxorubicin in other bladder cancer cell lines with wild-type p53 (wt-p53; three times in 253J and 13 times in KK47), but not in those with mutant-type p53 (TCCsup, J82 and EJ) or in RT112 p53DN. The combined treatment with dicoumarol suppressed p53/p21 induction by doxorubicin and resulted in sequential p38 MAPK activation, myeloid cell leukaemia 1 suppression and caspase cleavage. The synergistic effect of doxorubicin/dicoumarol was suppressed by the p38 MAPK inhibitor SB202190 and, furthermore, p21 knockdown with shRNA transfection made RT112 cells six times more susceptible to doxorubicin with p38 MAPK activation. CONCLUSION: These results suggest that concomitant use of dicoumarol could enhance the cytotoxicity of doxorubicin in urothelial cancer cells with wt-p53 through the p53/p21/p38 MAPK pathways. This combined treatment may provide a new therapeutic option to overcome chemoresistance in bladder cancer.

Skin necrosis during oral anticoagulant long-term treatment: an atypical side.

The effectiveness of anticoagulant therapy for venous thromboembolism, with regards to both acute phase and long term prophylaxis, in patients with recurrent deep venous thrombosis (DVT) and persistence of risk factors, has been confirmed by many studies. However, it is not free of complications such as hemorrhage or, more rarely, skin necrosis. The patient, observed by us since 1994, was treated with oral vitamin K antagonists: he was affected by post-thrombotic syndrome and deficiency of congenital procoagulant factors (factor II heterozygote and MTHFR positive heterozygote) and secondary deficiency of procoagulant factors due to the consumption of protein C, with appearance of skin necrosis that occurred after many years of oral anticoagulant treatment. The change of therapy from oral anticoagulant to low molecular weight heparin and the use of local dressing, led to the resolution of the clinical symptoms and on to healing.

[Recurrent vascular access trombosis associated with the prothrombin mutation G20210A in a adult patient in haemodialysis]. / Trombosis recurrente del acceso vascular asociada a la mutación G202 10A del gen de la protrombina en un paciente adulto en hemodiálisis.

Vascular access-related complications are a frequent cause of morbidity in haemodialysis patients and generate high costs. We present the case of an adult patient with end-stage renal disease and recurrent vascular access thrombosis associated with the prothrombin mutation G20210A and renal graft intolerance. The clinical expression of this heterozygous gene mutation may have been favoured by inflammatory state, frequent in dialysis patients. In this patient, the inflammatory response associated with the renal graft intolerance would have favored the development of recurrent vascular access thrombosis in a adult heterozygous for prothrombin mutation G20210A. In the case of early dysfunction of haemodialysis vascular access and after ruling out technical problems, it is convenient to carry out a screening for thrombophilia.

Trombosis recurrente del acceso vascular asociada a la mutación G20210A del gen de la protrombina en un paciente adulto en hemodiálisis / Recurrent vascular access trombosis associated with the prothrombin mutation G20210a in a adult patient in haemodialysis

Las complicaciones relacionadas con el acceso vascular (AV) son una causa frecuentede morbilidad de los pacientes en hemodiálisis (HD) y generan un elevadocoste. Presentamos el caso de un paciente adulto con insuficiencia renal crónicaterminal y trombosis repetidas del AV para hemodiálisis, asociado a lamutación G20210A del gen de la protrombina, en el contexto de una intoleranciaa un injerto renal no funcionante. La expresión clínica de este tipo de alteracionesde la coagulación, puede estar favorecida en el paciente en HD, por lapresencia de un estado inflamatorio, frencuente en estos pacientes. En este caso,la respuesta inflamatoria asociada a la intolerancia al injerto renal podría haberfavorecido la manifestación clínica en forma de trombosis de repetición del AV enun paciente heterocigoto para la mutación G20210A del gen de la protrombina.En los pacientes que desarrollan disfunción precoz del AV y no presentan problemasen la técnica de implantación, debe estudiarse la existencia de un estadoprotrombótico

Vascular access-related complications are a frequent cause of morbidity in haemodialysispatients and generate high costs. We present the case of an adult patient withend-stage renal disease and recurrent vascular access thrombosis associated with theprothrombin mutation G20210A and renal graft intolerance. The clinical expression of this heterozygous gene mutation may have been favoured by inflammatory state, frequentin dialysis patients. In this patient, the inflammatory response associated withthe renal graft intolerance would have favored the development of recurrent vascularaccess thrombosis in a adult heterozygous for prothrombin mutation G20210A. In thecase of early dysfunction of haemodialysis vascular access and after ruling out technicalproblems, it is convenient to carry out a screening for thrombophilia

Inhibition of DT-diaphorase potentiates the in vivo neurotoxic effect of intranigral injection of salsolinol in rats.

The present study shows that intranigral injection of dicoumarol, a DT-diaphorase inhibitor, potentiates the neurotoxic effect of salsolinol (salsolinol 1.25 nmoles plus dicoumarol 2 nmoles; in 2 microl). Rats treated with dicoumarol plus salsolinol presented a characteristic contralateral rotational behaviour when they were stimulated with apomorphine (0.5 mg/kg, s.c.), similar to rats injected unilaterally with 6-hydroxydopamine (6-OHDA). These rats also exhibited impairment of motor and cognitive behaviours. The results support the hypothesis that DT-diaphorase plays a protective role in the nigrostriatal dopaminergic systems.

Enhancing the oral bioavailability of the poorly soluble drug dicumarol with a bioadhesive polymer.

This article investigates the effect of particle size and the incorporation of a bioadhesive polymer, poly(fumaric-co-sebacic) anhydride p(FA:SA), on the relative bioavailability of dicumarol. A novel method was used to reduce particle size of the drug, and encapsulated formulations were fabricated using a phase inversion technique to produce nanospheres and microspheres with varying size. Groups of Yorkshire swine were catheterized and gavaged after fasting for 12 h with each formulation in a 50 mg/mL suspension. Blood was collected at different time points, from 0 to 96 h, and pharmacokinetic analysis revealed that formulations incorporating the smaller drug particles showed the highest bioavailability: micronized drug with 7% p(FA:SA) 17:83 polymer had 190% relative bioavailability, and phase inverted p(FA:SA) 17:83 microspheres with 31% (w/w) loading had 198% relative bioavailability to spray dried formulation. Formulations with larger drug particles achieved 71% relative bioavailability. A nonadhesive formulation, fabricated with poly(lactic acid) (PLA), showed 91% relative bioavailability. Both particle size and polymer composition play a role in oral absorption of dicumarol.

Dicoumarol: a unique microtubule stabilizing natural product that is synergistic with Taxol.

In studies on the antiproliferative actions of coumarin compounds, we discovered that dicoumarol (a coumarin anticoagulant; 3,3'-methylenebis[4-hydroxycoumarin]) inhibits the first cleavage of Strongylocentrotus purpuratus (sea urchin) embryos in a concentration-dependent manner with 50% inhibition occurring at a concentration of 10 microM. Because first cleavage in sea urchin embryos is highly selective for microtubule-targeted agents, we thought that the active compounds might inhibit cell division by interacting with tubulin or microtubules. We found that dicoumarol binds to bovine brain tubulin with a K(d) of 22 microM and that 0.1 microM dicoumarol strongly stabilizes the growing and shortening dynamics at the plus ends of the microtubules in vitro. Dicoumarol reduces the rate and extent of shortening, it increases the percentage of time the microtubules spend in an attenuated (paused) state, and it reduces the overall dynamicity of the microtubules. The antimitotic effects of the widely used cancer chemotherapeutic agent Taxol (paclitaxel) are also mediated by suppressing microtubule dynamics. We demonstrate that exposure to combinations of Taxol and dicoumarol results in a synergistic inhibition of cell division of sea urchin embryos. The results suggest that the antiproliferative mechanism of action of dicoumarol and possibly related pharmacophores may be mediated by tubulin binding and the stabilization of spindle microtubule dynamics. Because of its low toxicity and simple chemical structure, there is potential interest to explore combinations of antimitotic coumarins with other chemotherapeutic agents to improve efficacy and lower toxicity.

[Treatment of advanced Budd-Chiari syndrome by liver transplantation]. / Behandlung des fortgeschrittenen Budd-Chiari-Syndroms durch Lebertransplantation.

Budd-Chiari syndrome (BCS) with hepatic vein occlusion is a rare disorder that can effectively be treated in advanced stages with orthotopic liver transplantation. We report on 16 patients who received 18 liver grafts and were followed up for at least 2 years. In 7 patients a hematological disorder was confirmed by bone marrow biopsy. One patient died after 4 months due to cytomegalovirus pneumonia; another patient died after 2 years due to progressive liver failure after portal vein thrombosis. The actuarial 5-year survival rate is 87.5% compared to 85.3% in all other 710 orthotopic liver transplantations performed from September 1988 to December 1995 at our institution. Anticoagulation consisted of intravenous heparin and overlapping continuation with dicoumarin. Three patients received hydroxyurea for thrombocytosis, one patient for 1 week only early after the transplantation. Two postoperative abdominal hemorrhages required laparotomy. Two patients had to be retransplanted, one for thrombosis of the hepatic artery and portal vein after discontinuation of dicoumarin due to GI bleeding and one for hepatic vein thrombosis after insufficient dicoumarin intake. Terminal BCS represents a good indication for orthotopic liver transplantation; however, life-long, closely monitored anticoagulation is essential.

Biologically erodable microspheres as potential oral drug delivery systems.

Biologically adhesive delivery systems offer important advantages over conventional drug delivery systems. Here we show that engineered polymer microspheres made of biologically erodable polymers, which display strong adhesive interactions with gastrointestinal mucus and cellular linings, can traverse both the mucosal absorptive epithelium and the follicle-associated epithelium covering the lymphoid tissue of Peyer's patches. The polymers maintain contact with intestinal epithelium for extended periods of time and actually penetrate it, through and between cells. Thus, once loaded with compounds of pharmacological interest, the microspheres could be developed as delivery systems to transfer biologically active molecules to the circulation. We show that these microspheres increase the absorption of three model substances of widely different molecular size: dicumarol, insulin and plasmid DNA.

The duration of oral anticoagulant therapy after a second episode of venous thromboembolism. The Duration of Anticoagulation Trial Study Group.

BACKGROUND: A consensus has not been reached about the optimal duration of oral anticoagulant therapy after a second episode of venous thromboembolism. METHODS: In a multicenter trial, we compared six months of oral anticoagulant therapy with anticoagulant therapy continued indefinitely in patients who had had a second episode of venous thromboembolism. Of 227 patients enrolled, 111 were randomly assigned to six months of anticoagulation and 116 were assigned to receive anticoagulant therapy indefinitely; for both groups, the target international normalized ratio was 2.0 to 2.85. The initial episodes of deep-vein thrombosis (n = 193) and pulmonary embolism (n = 34), as well as recurrent episodes, were all objectively confirmed. RESULTS: After four years of follow-up, there were 26 recurrences of venous thromboembolism that fulfilled the diagnostic criteria, 23 in the group assigned to six months of therapy (20.7 percent) and 3 in the group assigned to continuing therapy (2.6 percent). The relative risk of recurrence in the group assigned to six months of therapy, as compared with the group assigned to therapy of indefinite duration, was 8.0 (95 percent confidence interval, 2.5 to 25.9). There were 13 major hemorrhages, 3 in the six-month group, (2.7 percent) and 10 in the infinite-treatment group (8.6 percent). The relative risk of major hemorrhage in the six-month group, as compared with the infinite-treatment group was 0.3 (95 percent confidence interval, 0.1 to 1.1). There was no difference in mortality between the two groups. CONCLUSIONS: Prophylactic oral anticoagulation that was continued for an indefinite period after a second episode of venous thromboembolism was associated with a much lower rate of recurrence during four years of follow-up than treatment for six months. However, there was a trend toward a higher risk of major hemorrhage when anticoagulation was continued indefinitely.

Radiotherapy, combined with simultaneous chemotherapy with mitomycin C and bleomycin for inoperable head and neck cancer--preliminary report.

PURPOSE: Prospectively designed randomized clinical study was undertaken to assess the efficacy of simultaneous application of irradiation, Mitomycin C, and Bleomycin in treatment of patients with inoperable head and neck carcinoma. METHODS AND MATERIALS: Between March 1991 and October 1993, 49 patients with inoperable head and neck carcinoma were randomly assigned to receive either radiation therapy alone (group A) or radiotherapy combined with simultaneous application of Mitomycin C and Bleomycin (group B). Patients in both groups were irradiated five times weekly with 2 Gy to the total dose of 66-70 Gy. Chemotherapy regimen included intramuscular application of Bleomycin 5 units twice a week, with the planned dose being 70 units and Mitomycin C 15 mg/m2 applied intravenously after delivery of 9-10 Gy of irradiation. The application of Mitomycin C was planned to be repeated on last day of radiotherapy in the dose of 10 mg/m2. In attempt to enhance the effect of chemotherapeutic drugs, patients in group B received also Nicotinamide, Chlorpromazine, and Dicoumarol. RESULTS: The difference in complete response rate between both treatment groups (24% in group A and 63% in group B) was statistically significant (p = 0.015). The difference in response rate was much more pronounced in patients with oropharyngeal carcinoma only (18% in group A compared to 81% in group B; p = 0.0003), while for all other subgroups added together, there was observed no benefit of multidrug therapy. Median follow-up was 18 months. Disease-free survival of patients in group A (9%) was significantly lower then in group B (48%) (p = 0.001). The difference between both treatment groups was even greater in patients with oropharyngeal carcinoma only: disease-free survival of these patients in group B was 66%, while in group A, all recurred (p = 0.00001). CONCLUSION: From results of our prospective randomized study it seems that the group of patients that received multidrug treatment with Mytomycin C, Bleomycin, Nicotinamide, Chlorpromazine, and Dicoumarol as enhancers of radiotherapy fared better than patients treated by radiotherapy alone.