Defibrotide: potential for treating endothelial dysfunction related to viral and post-infectious syndromes

INTRODUCTION

Defibrotide (DF) is a polyribonucleotide with antithrombotic, pro-fibrinolytic, and anti-inflammatory effects on endothelium. These effects and the established safety of DF present DF as a strong candidate to treat viral and post-infectious syndromes involving endothelial dysfunction.

AREAS COVERED

We discuss DF and other therapeutic agents that have the potential to target endothelial components of pathogenesis in viral and post-infectious syndromes. We introduce defibrotide (DF), describe its mechanisms of action, and explore its established pleiotropic effects on the endothelium. We describe the established pathophysiology of Coronavirus Disease 2019 (COVID-19) and highlight the processes specific to COVID-19 potentially modulated by DF. We also present influenza A and viral hemorrhagic fevers, especially those caused by hantavirus, Ebola virus, and dengue virus, as viral syndromes in which DF might serve therapeutic benefit. Finally, we offer our opinion on novel treatment strategies targeting endothelial dysfunction in viral infections and their severe manifestations.

EXPERT OPINION

Given the critical role of endothelial dysfunction in numerous infectious syndromes, in particular COVID-19, therapeutic pharmacology for these conditions should increasingly prioritize endothelial stabilization. Several agents with endothelial protective properties should be further studied as treatments for severe viral infections and vasculitides, especially where other therapeutic modalities have failed.

A Meta-Analysis Evaluating the Incidence of Bleeding Events With Intravenous Defibrotide Treatment Outside the Veno-Occlusive Disease/Sinusoidal Obstruction Syndrome Setting

Defibrotide is approved to treat hepatic veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) with renal/pulmonary dysfunction following hematopoietic cell transplantation (HCT) in adult and pediatric patients in the United States, and to treat severe hepatic VOD/SOS post-HCT in adult and pediatric patients aged >1 month in the European Union. The defibrotide prescribing information warns that defibrotide may increase bleeding risk in VOD/SOS patients. To broaden our understanding of the incidence of bleeding with defibrotide, we performed a meta-analysis of the published literature of defibrotide use outside of the post-HCT VOD/SOS setting. Of 1857 records identified, 125 reported on defibrotide; 23 contained data on bleeding events. The estimated overall incidence of bleeding events was 1% (95% confidence interval [CI]: 0%-2%) and 8% (95% CI: 3%-14%) in studies using intravenous defibrotide and studies with controls, respectively. The risk ratio for bleeding events with intravenous defibrotide versus controls was 0.36 (95% CI: 0.24-0.52; P < .00001) among studies with data on intravenous defibrotide and controls. This meta-analysis of defibrotide use outside of the post-HCT VOD/SOS setting suggests that the incidence of bleeding with defibrotide is lower than controls.

P1186PRELIMINARY RESULTS OF THE FIRST PHASE II CLINICAL TRIAL ON THE USE OF AN INNOVATIVE GLUCOSE-SPARING PD SOLUTION (FIRST)

Background and Aims

High amounts of glucose as the main osmotic agent for peritoneal dialysis (PD) could be harmful, as it may significantly increase cardiovascular morbidity and mortality. Glucose has long-term detrimental effects on the peritoneum, which ultimately may result in ultrafiltration failure, worsening fluid overload and cardiovascular disease. The absorption of glucose from the dialysate accentuates the disturbances of the carbohydrate metabolism, which is already impaired in the uremic state, leading to insulin resistance.

XyloCore (Iperboreal Pharma, Pescara, Italy), is a low glucose containing PD solution (PDS) proposed as an alternative to glucose PDS only regimen. It has been formulated replacing most of the glucose with two crystalloid agents, D-xylitol and L-carnitine.

PDS containing osmolar agents like xylitol and L-Carnitine added to glucose, used for the nocturnal exchange, may lead to a significant reduction of glucose level in PDS during the night dwell, while preserving or even improving the depurative efficacy of the standard PDS containing 2.5% glucose. The reduction of glucose level could be further enhanced if the PDS with xylitol and carnitine will be used for the diurnal exchanges and a PDS with icodextrin will substitute the standard PDS containing glucose 2.5% for the nocturnal dwell.

The aims of the study are to evaluate the effects of (I) the XyloCore PDS IPX15 [containing glucose (0.5%), xylitol (1.5%) and L-carnitine (0.02%) as osmotic agents, as compared to the standard 2.5% glucose PDS] for the nocturnal exchange, and (II) the XyloCore PDS IPX07 [containing glucose (0.5%), xylitol (0.7%) and L-carnitine (0.02%), as compared to the standard 1.5% glucose PDS] for the diurnal (short dwell) exchanges.

Method

Prospective, randomized, controlled clinical trial in stable ESRD patients treated by CAPD (study protocol registered as NCT 04001036). Key inclusion criteria are: ESRD treated for at least three months with CAPD, stable clinical condition within the four weeks before the screening, hemoglobin ≥ 9g/dL, absence of acute peritonitis and/or peritoneal catheter infection in the three months before. Key exclusion criteria are: androgen therapy, active infections, congestive heart failure stage III and IV NYHA; major cardiovascular events in the last 3 months, clinically relevant cardiac arrhythmia; clinically relevant abnormal hepatic tests; treatment with L-carnitine in the previous three months, pregnancy, life expectancy of less than one year, allergy to L-carnitine or xylitol. The sample size is 40 patients. Treatment duration is 4 weeks plus a 4 weeks safety follow up with no treatment. Primary end-point is the daily peritoneal ultrafiltration volume. Secondary end-points are the peritoneal equilibration test (D/P creatinine, D/P glucose), weekly total Kt/V urea, weekly total creatinine clearance, Adverse Events.

Results

Two centers participate in the study. One center has so far recruited 10 patients, 6 in the IPX15 group and 4 in the IXP07 group. The six patients in the IXP15 group were 4 males and 2 males, aged 69.5 ±5.1 years. The four patients in the IXP07 were all male, mean age 56 ± 12 years. One patient already completed the study period. Results for Kt/V, creatinine clearance, D/P creatinine, D/P glucose, ultrafiltration volume, at time (T) 0 are 1.17, 85.6, 0.75, 0.18, 400 ml, respectively; at T28 (days) are 3.1, 80, 0.82, 0.23, 400 ml respectively, and at T56 are 3.5, 80, 0.77, 023, 450 ml, respectively. D/P glucose results indicate that this patient is a high transporter and D/P creatinine that the patient was an average/ high transporter.

There were no adverse events reported and tolerability has been excellent so far.

Conclusion

In the first 10 ESRD patients included in the study, XyloCore PDS used for 4 weeks has been well tolerated without significant adverse events. The study is in progress.

P1136STUDY DESIGN OF ELIXIR, A MULTICENTER EUROPEAN PHASE III CLINICAL TRIAL AIMED TO TEST A GLUCOSE-SPARING PD SOLUTION WHERE GLUCOSE IS MOSTLY REPLACED WITH OSMO-METABOLIC AGENTS

Background and Aims

Peritoneal dialysis (PD) faces particular challenges that include multiple barriers to the therapy and unsatisfactory and poorly defined technique survival as well as limitations relating to peritoneal membrane longevity and metabolic alterations. Glucose is the most used osmotic agent for PD. However, the peritoneal membrane is not impermeable to glucose, so that a rapid reduction of the osmotic gradient and an increase of serum carbohydrates are seen in CAPD patients. Increased glucose absorption may result in metabolic abnormalities like hyperglycemia, hyperinsulinemia, obesity and hyperlipidemia. Therefore, a more satisfactory composition of PD solution (PDS) is urgently needed.

XyloCore PDS (Iperboreal Pharma, Pescara, Italy) has been formulated to significantly reduce glucose exposure by replacing most of it with two crystalloid agents, D-xylitol and L-carnitine.

A randomized controlled trial to evaluate the safety and efficacy of a newly introduced PDS is needed to provide the necessary clinical evidence to guide policy decision-making. The randomized controlled study designs in small populations are challenging because it is very difficult to adequately assess changes between variable groups.

The aim of this program was to develop an adequate clinical trial protocol and validate it by reaching agreement with regulatory authorities.

Method

Pre-approval trials include a study protocol and test the drug in a highly selected patient population designed to provide the most robust evidence on the drug’s benefits and risks.

The scientific integrity of the trial and the credibility of the data from the trial depend substantially on the trial design, including the primary and secondary endpoints, minimization of bias (including randomization and blinding), “discontinuation criteria” for individual subjects, statistical analysis of primary end-point, and the strategy to handle missing data.

An international steering committee of clinical experts and statistician has been set for this study to discuss and develop an adequate study protocol to produce evidence to support regulatory submissions. The proposed protocol has been discussed with the regulatory agency in Germany BfArM in order to reach agreement on the study design for this Phase 3 pre-approval trial.

Results

BfArM agreed with the proposed study design for the planned pivotal phase III study NCT03994471.The study will be a randomized, controlled parallel groups, open, multicenter study, comparing the effects of the low glucose PD solution, XyloCore, to glucose regimen only, in ESRD patients receiving CAPD. All patients will receive 7.5% Icodextrin for nocturnal (long-dwell) exchange. Randomization will be performed centrally and the study will be stratified for diabetic/non-diabetic patients. The primary objective is to demonstrate the non-inferiority of XyloCore compared to the glucose PDS with regards to safety and efficacy. The primary outcome measure is total weekly Kt/V urea after a 24-week period using the assigned PD solution, assessed using a peritoneal function test. The non-inferiority margin of -0.25 with a 1-sided level of significance of 2.5% and 80% power has been agreed (Kt/V will not be less than 1.7 at any time). Consequently, a sample size of 170 patients has been defined. The Agency agreed that the study cannot be blinded and recommended a blinded and independent assessment of the end-point Kt/V urea. A Feasibility Study is in progress to identify the centers in several countries.

Conclusion

A well written and complete protocol is essential for a high-quality study. Many clinical studies have problems with incompleteness, ambiguity and inconsistency. Many of these problems are avoidable by careful planning during the protocol writing process. Involving regulatory authorities early in the discussion of the protocol should ensure acceptability of study design of pre-approval clinical trials.

A radio ridge connecting two galaxy clusters in a filament of the cosmic web

Galaxy clusters are the most massive gravitationally bound structures in the Universe. They grow by accreting smaller structures in a merging process that produces shocks and turbulence in the intracluster gas. We observed a ridge of radio emission connecting the merging galaxy clusters Abell 0399 and Abell 0401 with the Low-Frequency Array (LOFAR) telescope network at 140 megahertz. This emission requires a population of relativistic electrons and a magnetic field located in a filament between the two galaxy clusters. We performed simulations to show that a volume-filling distribution of weak shocks may reaccelerate a preexisting population of relativistic particles, producing emission at radio wavelengths that illuminates the magnetic ridge.

Needle-like structures discovered on positively charged lightning branches

Lightning is a dangerous yet poorly understood natural phenomenon. Lightning forms a network of plasma channels propagating away from the initiation point with both positively and negatively charged ends-called positive and negative leaders¹. Negative leaders propagate in discrete steps, emitting copious radio pulses in the 30-300-megahertz frequency band^2-8 that can be remotely sensed and imaged with high spatial and temporal resolution^9-11. Positive leaders propagate more continuously and thus emit very little high-frequency radiation¹². Radio emission from positive leaders has nevertheless been mapped^13-15, and exhibits a pattern that is different from that of negative leaders^11-13,16,17. Furthermore, it has been inferred that positive leaders can become transiently disconnected from negative leaders^{9,12,16,18-20}, which may lead to current pulses that both reconnect positive leaders to negative leaders^{11,16,17,20-22} and cause multiple cloud-to-ground lightning events¹. The disconnection process is thought to be due to negative differential resistance¹⁸, but this does not explain why the disconnections form primarily on positive leaders²², or why the current in cloud-to-ground lightning never goes to zero²³. Indeed, it is still not understood how positive leaders emit radio-frequency radiation or why they behave differently from negative leaders. Here we report three-dimensional radio interferometric observations of lightning over the Netherlands with unprecedented spatiotemporal resolution. We find small plasma structures-which we call 'needles'-that are the dominant source of radio emission from the positive leaders. These structures appear to drain charge from the leader, and are probably the reason why positive leaders disconnect from negative ones, and why cloud-to-ground lightning connects to the ground multiple times.

Final results from a defibrotide treatment-IND study for patients with hepatic veno-occlusive disease/sinusoidal obstruction syndrome

Hepatic veno‐occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) is a potentially life‐threatening complication of haematopoietic stem cell transplant (HSCT) conditioning and chemotherapy. Defibrotide is approved for treatment of hepatic VOD/SOS with pulmonary or renal dysfunction [i.e., multi‐organ dysfunction (MOD)] after HSCT in the United States and severe VOD/SOS after HSCT in patients aged older than 1 month in the European Union. Defibrotide was available as an investigational drug by an expanded‐access treatment programme (T‐IND; NCT00628498). In the completed T‐IND, the Kaplan–Meier estimated Day +100 survival for 1000 patients with documented defibrotide treatment after HSCT was 58·9% [95% confidence interval (CI), 55·7–61·9%]. Day +100 survival was also analysed by age and MOD status, and post hoc analyses were performed to determine Day +100 survival by transplant type, timing of VOD/SOS onset (≤21 or >21 days) and timing of defibrotide treatment initiation after VOD/SOS diagnosis. Day +100 survival in paediatric patients was 67·9% (95% CI, 63·8–71·6%) and 47·1% (95% CI, 42·3–51·8%) in adults. All patient subgroups without MOD had higher Day +100 survival than those with MOD; earlier defibrotide initiation was also associated with higher Day +100 survival. The safety profile of defibrotide in the completed T‐IND study was similar to previous reports.

Progress in the contemporary management of hemophilia: The new issue of patient aging

The management of inherited coagulation disorders such as hemophilia A and B has witnessed dramatic progresses since the last few decades of the last century. Accordingly, persons with hemophilia (PWH) now enjoy a life expectancy at birth not different from that of males in the general population, at least in high income countries. Nowadays, a substantial proportion of PWH are aging, like their peers in the general population. This outstanding progress is accompanied by problems that are in part similar to those of any old person (multiple concomitant diseases and the resulting intake of multiple drugs other than those specific for hemophilia treatment). In addition, older PWH suffer from the consequences of the comorbidities that developed when their treatment was at the same time poorly available and unsafe. Typical hemophilia comorbidities affect the musculoskeletal system following joint and muscle bleeds, but also the liver and kidney are often impaired due to previous bloodborne infections such as viral hepatitis and HIV. Thus, the comorbidities of hemophilia superimposed on the multimorbidity and polypharmacy associated with aging create peculiar problems in the current management of these patients, that demand the coordinated holistic intervention of internists, geriatricians and clinical pharmacologists in addition to the care traditionally provided by pediatricians and hematologists.

Recombinant Factor VIIa–Mediated Activation of Prothrombin Complex Concentrates

Recombinant factor VIIa (rFVIIa) is used in the management of bleeding in patients with hemophilia. A generic biosimilar version of NovoSeven is also developed (AryoSeven). To compare the activation profile of NovoSeven and AryoSeven, 2 commercially available protein complex concentrates (PCCs) were used. Profilnine activated by RecombiPlasTin 2G resulted in conversions of prothrombin to prethrombin and thrombin at 5 to 30 minutes. However, addition of rFVIIa at final concentration range of 0.25 to 0.5 µg/mL to the same mixture resulted in total conversion of prothrombin to thrombin with a doublet at 36 kDa. Recombinant factor VIIa alone did not generate thrombin in native Beriplex, and the addition of rFVIIa to Beriplex failed to generate thrombin. Beriplex activated by RecombiPlasTin 2G resulted in complete conversion of prothrombin to thrombin. Both NovoSeven and AryoSeven exhibited similar activation profiles. These studies indicate that the activation of PCCs by both rFVIIa preparations results in comparable generation of thrombin.

Defibrotide for Patients with Hepatic Veno-Occlusive Disease/Sinusoidal Obstruction Syndrome: Interim Results from a Treatment IND Study

Hepatic veno-occlusive disease, or sinusoidal obstruction syndrome (VOD/SOS), is a serious and potentially fatal complication of conditioning for hematopoietic stem cell transplantation (HSCT) or of chemotherapy regimens alone. Defibrotide is a complex mixture of single-stranded polydeoxyribonucleotides that is approved in the United States for treating hepatic VOD/SOS with renal or pulmonary dysfunction post-HSCT and in the European Union, Israel, and South Korea for treating severe hepatic VOD/SOS post-HSCT. Defibrotide was previously available in the United States as an investigational drug through a treatment protocol (treatment IND) study. Interim results of that large, treatment IND study of patients with VOD/SOS and with or without multiorgan dysfunction (MOD; also known as multiorgan failure) are presented here. Defibrotide was administered i.v. at 6.25 mg/kg every 6 hours (25 mg/kg/day), with a recommended treatment duration of at least 21 days. Enrolled patients (n = 681) were diagnosed with VOD/SOS based on Baltimore or modified Seattle criteria or liver biopsy analysis. Among the 573 HSCT recipients, 288 (50.3%; 95% confidence interval [CI], 46.2% to 54.4%) were alive at day +100 post-HSCT. Day +100 survival for the pediatric (≤16 years) and adult (>16 years) subgroups was 54.5% (95% CI, 49.1% to 60.0%; n = 174 of 319) and 44.9% (95% CI, 38.8% to 51.0%; n = 114 of 254), respectively. In the MOD subgroup, 159 of 351 patients (45.3%; 95% CI, 40.1% to 50.5%) of patients were alive at day +100 post-HSCT. Treatment with defibrotide was generally well tolerated, and drug-related toxicities were consistent with previous studies. Adverse events were reported in 69.6% of safety-evaluable patients (399 of 573). Other than VOD/SOS and associated MOD symptoms, the most commonly reported treatment-emergent adverse event was hypotension (13.8%). Day +100 survival results observed in this trial were consistent with results seen in previous trials of defibrotide for VOD/SOS in adult and pediatric patients. These data support the potential benefit of defibrotide in treating a VOD/SOS patient population that includes those with and without MOD.

Defibrotide for the Treatment of Hepatic Veno-Occlusive Disease: Final Results From the International Compassionate-Use Program

Hepatic veno-occlusive disease, also called sinusoidal obstruction syndrome (VOD/SOS), is an unpredictable and potentially fatal complication of hematopoietic cell transplantation (HCT) or nontransplantation-associated chemotherapy/radiotherapy. In cases of severe hepatic VOD/SOS, typically defined by associated multiorgan failure (MOF, also known as multiorgan dysfunction), mortality exceeds 80%. Preclinical and early clinical data have provided a rationale for defibrotide treatment in hepatic VOD/SOS. Based on this evidence and in recognition of the dismal prognosis for these patients, defibrotide was made available through an international multicenter compassionate-use program conducted from December 1998 to March 2009. Physicians participating in the program voluntarily provided demographic and outcome data for patients given defibrotide. Efficacy and safety analyses were performed using the data received for 710 treated patients. Defibrotide was given at 10, 25, 40, 60, or 80 mg/kg/day for a median of 15 days (range, 1 to 119 days). By Kaplan-Meier analysis, the estimated overall day +100 survival was 54% (58% in the 25 mg/kg/day dose group). Adverse events (AEs) were reported in 53% of patients. The most common AEs were MOF, progression of hepatic VOD/SOS, sepsis, and graft-versus-host disease, which were consistent with the AEs expected for this patient population. No clinically meaningful trends in AEs were identified by gender, age, or dose group. Safety and efficacy resultswere consistent with prior studies of defibrotide in hepatic VOD/SOS, and subgroup analyses lend support to the use of the 25 mg/kg/day dose.

Phase 3 trial of defibrotide for the treatment of severe veno-occlusive disease and multi-organ failure

Hepatic veno-occlusive disease (VOD), also called sinusoidal obstruction syndrome (SOS), is a potentially life-threatening complication of hematopoietic stem cell transplantation (HSCT). Untreated hepatic VOD/SOS with multi-organ failure (MOF) is associated with >80% mortality. Defibrotide has shown promising efficacy treating hepatic VOD/SOS with MOF in phase 2 studies. This phase 3 study investigated safety and efficacy of defibrotide in patients with established hepatic VOD/SOS and advanced MOF. Patients (n = 102) given defibrotide 25 mg/kg per day were compared with 32 historical controls identified out of 6867 medical charts of HSCT patients by blinded independent reviewers. Baseline characteristics between groups were well balanced. The primary endpoint was survival at day +100 post-HSCT; observed rates equaled 38.2% in the defibrotide group and 25% in the controls (23% estimated difference; 95.1% confidence interval [CI], 5.2-40.8;P= .0109, using a propensity-adjusted analysis). Observed day +100 complete response (CR) rates equaled 25.5% for defibrotide and 12.5% for controls (19% difference using similar methodology; 95.1% CI, 3.5-34.6;P= .0160). Defibrotide was generally well tolerated with manageable toxicity. Related adverse events (AEs) included hemorrhage or hypotension; incidence of common hemorrhagic AEs (including pulmonary alveolar [11.8% and 15.6%] and gastrointestinal bleeding [7.8% and 9.4%]) was similar between the defibrotide and control groups, respectively. Defibrotide was associated with significant improvement in day +100 survival and CR rate. The historical-control methodology offers a novel, meaningful approach for phase 3 evaluation of orphan diseases associated with high mortality. This trial was registered at www.clinicaltrials.gov as #.

Defibrotide for prophylaxis of hepatic veno-occlusive disease in paediatric haemopoietic stem-cell transplantation: an open-label, phase 3, randomised controlled trial

BACKGROUND

Hepatic veno-occlusive disease is a leading cause of morbidity and mortality after haemopoietic stem-cell transplantation (HSCT). We aimed to assess whether defibrotide can reduce the incidence of veno-occlusive disease in this setting.

METHODS

In our phase 3 open-label, randomised controlled trial, we enrolled patients at 28 European university hospitals or academic medical centres. Eligible patients were younger than 18 years, had undergone myeloablative conditioning before allogeneic or autologous HSCT, and had one or more risk factor for veno-occlusive disease based on modified Seattle criteria. We centrally assigned eligible participants on the basis of a computer-generated randomisation sequence (1:1), stratified by centre and presence of osteopetrosis, to receive intravenous defibrotide prophylaxis (treatment group) or not (control group). The primary endpoint was incidence of veno-occlusive disease by 30 days after HSCT, adjudicated by a masked, independent review committee, in eligible patients who consented to randomisation (intention-to-treat population), and was assessed with a competing risk approach. Patients in either group who developed veno-occlusive disease received defibrotide for treatment. We assessed adverse events to 180 days after HSCT in all patients who received allocated prophylaxis. This trial is registered with ClinicalTrials.gov, number NCT00272948.

FINDINGS

Between Jan 25, 2006, and Jan 29, 2009, we enrolled 356 eligible patients to the intention-to-treat population. 22 (12%) of 180 patients randomly allocated to the defibrotide group had veno-occlusive disease by 30 days after HSCT compared with 35 (20%) of 176 controls (risk difference -7·7%, 95% CI -15·3 to -0·1; Z test for competing risk analysis p=0·0488; log-rank test p=0·0507). 154 (87%) of 177 patients in the defibrotide group had adverse events by day 180 compared with 155 (88%) of 176 controls.

INTERPRETATION

Defibrotide prophylaxis seems to reduce incidence of veno-occlusive disease and is well tolerated. Thus, such prophylaxis could present a useful clinical option for this serious complication of HSCT.

FUNDING

Gentium SpA, European Group for Blood and Marrow Transplantation.

Defibrotide interferes with several steps of the coagulation-inflammation cycle and exhibits therapeutic potential to treat severe malaria

OBJECTIVE

The coagulation-inflammation cycle has been implicated as a critical component in malaria pathogenesis. Defibrotide (DF), a mixture of DNA aptamers, displays anticoagulant, anti-inflammatory, and endothelial cell (EC)-protective activities and has been successfully used to treat comatose children with veno-occlusive disease. DF was investigated here as a drug to treat cerebral malaria.

METHODS AND RESULTS

DF blocks tissue factor expression by ECs incubated with parasitized red blood cells and attenuates prothrombinase activity, platelet aggregation, and complement activation. In contrast, it does not affect nitric oxide bioavailability. We also demonstrated that Plasmodium falciparum glycosylphosphatidylinositol (Pf-GPI) induces tissue factor expression in ECs and cytokine production by dendritic cells. Notably, dendritic cells, known to modulate coagulation and inflammation systemically, were identified as a novel target for DF. Accordingly, DF inhibits Toll-like receptor ligand-dependent dendritic cells activation by a mechanism that is blocked by adenosine receptor antagonist (8-p-sulfophenyltheophylline) but not reproduced by synthetic poly-A, -C, -T, and -G. These results imply that aptameric sequences and adenosine receptor mediate dendritic cells responses to the drug. DF also prevents rosetting formation, red blood cells invasion by P. falciparum and abolishes oocysts development in Anopheles gambiae. In a murine model of cerebral malaria, DF affected parasitemia, decreased IFN-γ levels, and ameliorated clinical score (day 5) with a trend for increased survival.

CONCLUSION

Therapeutic use of DF in malaria is proposed.

Defibrotide blunts the prothrombotic effect of thalidomide on endothelial cells

Patients with multiple myeloma (MM) are at relatively high risk of developing thromboembolic events such deep venous thrombosis (DVT) where thalidomide therapy has been identified to increase this risk. Defibrotide (DF), a polydisperse oligonucleotide, showed previously to counteract the alterations in endothelial cells (ECs) induced by lipopolysaccharide. It prompts us to investigate the impact of thalidomide on ECs and whether DF modulates changes in fibrinolysis induced by thalidomide. In this in vitro study, MM by itself alters the profibrinolytic potential of ECs decreasing the tissue plasminogen activator (t-PA) and increasing the plasminogen activator inhibitor 1 (PAI-1) levels which is potentiated by thalidomide. Defibrotide was able to counteract these effects. Additionally, DF upregulated the t-PA and downregulated PAI-1 gene expression modulated by thalidomide. Defibrotide also protects ECs from thalidomide-mediated cell death without interfering with its antitumor effects. These findings support DF clinical use for the prevention of DVT induced by immunomodulatory drugs.

Defibrotide for the treatment of severe hepatic veno-occlusive disease and multiorgan failure after stem cell transplantation: a multicenter, randomized, dose-finding trial

Therapeutic options for severe hepatic veno-occlusive disease (VOD) are limited and outcomes are dismal, but early phase I/II studies have suggested promising activity and acceptable toxicity using the novel polydisperse oligonucleotide defibrotide. This randomized phase II dose-finding trial determined the efficacy of defibrotide in patients with severe VOD following hematopoietic stem cell transplantation (HSCT) and identified an appropriate dose for future trials. Adult and pediatric patients received either lower-dose (arm A: 25 mg/kg/day; n = 75) or higher-dose (arm B: 40 mg/kg/day; n = 74) i.v. defibrotide administered in divided doses every 6 hours for > or =14 days or until complete response, VOD progression, or any unacceptable toxicity occurred. Overall complete response and day +100 post-HSCT survival rates were 46% and 42%, respectively, with no significant difference between treatment arms. The incidence of treatment-related adverse events was low (8% overall; 7% in arm A, 10% in arm B); there was no significant difference in the overall rate of adverse events between treatment arms. Early stabilization or decreased bilirubin was associated with better response and day +100 survival, and decreased plasminogen activator inhibitor type 1 (PAI-1) during treatment was associated with better outcome; changes were similar in both treatment arms. Defibrotide 25 or 40 mg/kg/day also appears effective in treating severe VOD following HSCT. In the absence of any differences in activity, toxicity or changes in PAI-1 level, defibrotide 25 mg/kg/day was selected for ongoing phase III trials in VOD.

Melphalan, prednisone, thalidomide and defibrotide in relapsed/refractory multiple myeloma: results of a multicenter phase I/II trial

BACKGROUND

Defibrotide is a novel orally bioavailable polydisperse oligonucleotide with anti-thrombotic and anti-adhesive effects. In SCID/NOD mice, defibrotide showed activity in human myeloma xenografts. This phase I/II study was conducted to identify the most appropriate dose of defibrotide in combination with melphalan, prednisone and thalidomide in patients with relapsed and relapsed/refractory multiple myeloma, and to determine its safety and tolerability as part of this regimen.

DESIGN AND METHODS

This was a phase I/II, multicenter, dose-escalating, non-comparative, open label study. Oral melphalan was administered at a dose of 0.25 mg/kg on days 1-4, prednisone at a dose of 1.5 mg/kg also on days 1-4 and thalidomide at a dose of 50-100 mg/day continuously. Defibrotide was administered orally at three dose-levels: 2.4, 4.8 or 7.2 g on days 1-4 and 1.6, 3.2, or 4.8 g on days 5-35.

RESULTS

Twenty-four patients with relapsed/refractory multiple myeloma were enrolled. No dose-limiting toxicity was observed. In all patients, the complete response plus very good partial response rate was 9%, and the partial response rate was 43%. The 1-year progression-free survival and 1-year overall survival rates were 34% and 90%, respectively. The most frequent grade 3-4 adverse events included neutropenia, thrombocytopenia, anemia and fatigue. Deep vein thrombosis was reported in only one patient.

CONCLUSIONS

This combination of melphalan, prednisone and thalidomide together with defibrotide showed anti-tumor activity with a favorable tolerability. The maximum tolerated dose of defibrotide was identified as 7.2 g p.o. on days 1-4 followed by 4.8 g p.o. on days 5-35. Further trials are needed to confirm the role of this regimen and to evaluate the combination of defibrotide with new drugs.

Drug safety information through the internet: the experience of an Italian website

BACKGROUND

The Internet may play a crucial role in the prompt provision of updated drug safety information. Nevertheless, limited knowledge of the English language among healthcare professionals or suboptimal search skills constitute barriers to widespread and appropriate use of the Internet for this purpose in Italy. In order to provide accurate information on drug safety and to promote the reporting of adverse drug reactions, in 1999 the clinical section of the Italian Society of Pharmacology created the website www.farmacovigilanza.org, financially supported by a non-profit foundation. The website promptly and independently provides news published in the international literature on drug safety, translated into Italian. The site also contains specific sections dedicated to adverse reactions to herbal products and cosmetic preparations.

OBJECTIVES

The aim of this paper was to describe the number and characteristics of users and the most intensively visited sections of the website. Furthermore, in September 2006, 300 registered users who had accessed a registered users area aimed specifically at health professionals more than 20 times in the preceding 12 months received a ten-item multiple choice questionnaire via e-mail, to assess satisfaction with the accuracy and promptness of information provided, text comprehension and other information sources for drug-related issues. We hereby describe the results of the survey, after careful analysis of the questionnaires.

RESULTS

Up until July 2007, the site had over 600 000 direct accesses and 9760 healthcare professionals registered to use the site. A total of 108 responses to the e-mailed questionnaire were received (response rate = 36%), of which 103 were analysed; five were excluded due to missing information. Overall, the majority of responders judged the information on the site as objective and understandable. More than 85% of participants declared that the site has influenced their opinion and attitudes toward the safety of medicines. In particular, responders said that they pay more attention to drug interactions and to the safety profile of newly marketed drugs, and spend more time on communicating the risks of drugs used by their patients. Specifically, responders stated that they pay more attention to drug interactions (87.7%), newly marketed drugs (68.5%), herbal remedies (56.2%), drugs in patients at increased risk (42.5%), drugs in pregnant women (42.5%) and cosmetics (13.7%).

CONCLUSIONS

The website www.farmacovigilanza.org appears to be an effective tool that provides users of the site with independent, relevant and reliable safety information. It was found to influence (and possibly improve) the quality of prescribing of a large proportion of the general practitioners who responded to our questionnaire, and our results indicate a high appreciation of the information found on the website. Moreover, the survey disclosed that there is a substantial need for such information in the national language by healthcare professionals. We think that our approach can serve as a model for similar initiatives in countries elsewhere in the world.

Preclinical studies in support of defibrotide for the treatment of multiple myeloma and other neoplasias

PURPOSE OF THE STUDY

Defibrotide, an orally bioavailable polydisperse oligonucleotide, has promising activity in hepatic veno-occlusive disease, a stem cell transplantation-related toxicity characterized by microangiopathy. The antithrombotic properties of defibrotide and its minimal hemorrhagic risk could serve for treatment of cancer-associated thrombotic complications. Given its cytoprotective effect on endothelium, we investigated whether defibrotide protects tumor cells from cytotoxic antitumor agents. Further, given its antiadhesive properties, we evaluated whether defibrotide modulates the protection conferred to multiple myeloma cells by bone marrow stromal cells.

METHODS-RESULTS

Defibrotide lacks significant single-agent in vitro cytotoxicity on multiple myeloma or solid tumor cells and does not attenuate their in vitro response to dexamethasone, bortezomib, immunomodulatory thalidomide derivatives, and conventional chemotherapeutics, including melphalan and cyclophosphamide. Importantly, defibrotide enhances in vivo chemosensitivity of multiple myeloma and mammary carcinoma xenografts in animal models. In cocultures of multiple myeloma cells with bone marrow stromal cells in vitro, defibrotide enhances the multiple myeloma cell sensitivity to melphalan and dexamethasone, and decreases multiple myeloma-bone marrow stromal cell adhesion and its sequelae, including nuclear factor-kappaB activation in multiple myeloma and bone marrow stromal cells, and associated cytokine production. Moreover, defibrotide inhibits expression and/or function of key mediators of multiple myeloma interaction with bone marrow stromal cell and endothelium, including heparanase, angiogenic cytokines, and adhesion molecules.

CONCLUSION

Defibrotide's in vivo chemosensitizing properties and lack of direct in vitro activity against tumor cells suggest that it favorably modulates antitumor interactions between bone marrow stromal cells and endothelia in the tumor microenvironment. These data support clinical studies of defibrotide in combination with conventional and novel therapies to potentially improve patient outcome in multiple myeloma and other malignancies.

Co-transfer of embryos derived from cryopreserved and fresh natural cycle oocytes: a pilot study

Italian legislation regarding reproductive medicine prohibits embryo storage while allowing cryopreservation of supernumerary oocytes. This study evaluated the effect of fresh oocytes obtained from natural unstimulated cycles on the clinical success rates derived from the use of frozen-thawed (FR-TH) oocytes obtained following ovarian stimulation. For 36 women, intracytoplasmic sperm injection was performed on FR-TH oocytes supplemented by a fresh oocyte, if available, derived from a natural cycle in which gonadotrophin-releasing hormone-antagonist was used for premature LH surge control. The retrieval rate of fresh oocytes was 61.1% and survival rate of FR-TH oocytes was 43.6%. The fertilization rate of fresh and FR-TH oocytes was 70% and 52.5%, respectively. Fifty embryos were transferred, 14 of them developed from fresh oocytes and 36 from FR-TH oocytes. Six pregnancies occurred in 10 cycles in which the embryos developed from fresh and FR-TH oocytes (pregnancy rate 60.0%) and two in 12 patients in whom the embryos were obtained from only FR-TH oocytes (pregnancy rate 16.7%) (P < 0.05). In summary, the data demonstrate that the transfer of embryos derived from oocytes cryopreserved following a previous ovarian stimulation and an embryo developed from a fresh one retrieved in natural cycle ensures an excellent clinical outcome.

Hopes and facts about mild ovarian stimulation

Over the last two decades, easier and less expensive stimulation treatments have been largely replaced by more complex and more demanding protocols. Since the mid-nineties, long-term gonadotrophin-releasing hormone agonist stimulation protocols have been widely used. Such lengthy expensive regimens are not free from short- and long-term risks and complications. Mild stimulation protocols reduce the mean number of days of stimulation, the total amount of gonadotrophins used and the mean number of oocytes retrieved. The proportion of high quality and euploid embryos seems to be higher compared with conventional stimulation protocols and the pregnancy rate per embryo transfer is comparable. Moreover, the reduced costs, the better tolerability for patients and the less time needed to complete an IVF cycle make mild approaches clinically and cost-effective over a given period of time. However, further prospective randomized studies are needed to compare cumulative pregnancy rates between the two protocols. Natural cycle IVF, with minimal stimulation, has been recently proposed as an alternative to conventional stimulation protocols in normo- and poor responder patients. Although acceptable results have been reported, further large prospective randomized studies are needed to better evaluate the efficacy of these minimal regimens compared with conventional stimulation approaches.

Pre-clinical evidence for an anti-tumor activity of defibrotide, a DNA-based, endothelium stabilizing drug

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Background: Defibrotide (DF) is a mixture of polydeoxyribonucleotides with anti-thrombotic activity. Next to endothelium stabilization, recent data suggest anti-neoplastic properties of DF modulating interactions of tumor cells with their microenvironment. We investigated whether DF regulates expression and activity of heparanase, an enzyme critically involved in breaking down extracellular barriers and releasing growth factors linked to tumor invasion and angiogenesis. Methods: Heparanase expression was tested by RT-PCR and flow cytometry with multiple myeloma (MM) and microvascular endothelial cells. Heparanase activity was measured in cellular extracts with a heparan-degrading enzymatic assay. Serum degradation products of DF were identified by SEC-HPLC. The anti-angiogenic potential of DF was tested in vitro using a kit with human microvascular endothelial cells forming tubes across a layer of fibroblasts. In vivo, DF was tested in the dorsal skin-fold chamber assay in mice after inoculation of human gastric cancer cells. Proliferation was assessed by trypan blue exclusion. Results: We demonstrate a striking downregulation of expression and enzymatic activity of heparanase in endothelial as well as MM cells. In contrast, the degradation products of DF failed to exert any biological activity, suggesting that the intact mixture of deoxyoligonucleotides is responsible for the anti-tumor effect. We could also show that DF prevents (tumor) angiogenesis in vitro and in vivo. Western blots suggest that DF reduces phosphorylation-activation of p70S6 kinase, a key target in the mTOR pathway linked to angiogenesis. In addition, DF does not influence proliferation of vascular or tumor cells, rather acts via selective inhibition of tube formation of endothelial cells. Conclusion: In the present report we provide evidence for an anti-tumor activity of DF. DF inhibits (tumor) vessel formation and heparanase activity, and thus should be considered as an anti-cancer agent.

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Differentiation of human tumour-associated dendritic cells into endothelial-like cells: an alternative pathway of tumour angiogenesis

Until recently, the only accepted mechanism of tumour vascularization was the sprouting of endothelial cells (EC) from pre-existing vessels, while recent studies suggest the contribution of stem cell-derived endothelial progenitors as well as cells from the myeloid lineage. Here, we show a new way of endothelial differentiation that involves the specific modulation of monocytes by the tumour environment. The tumour milieu is characterized by the presence of cytokines and lactate which induce the differentiation of tumour-invading monocytes into tumour-associated dendritic cells (DC). Additional incubation of tumour-associated DC with pro-angiogenic factors, such as vascular endothelial growth factor and oncostatin M, led to transdifferentiation into endothelial-like cells. The cells showed strong expression of von Willebrand factor and VE-Cadherin, both classical EC markers, while leukocytic markers were reduced. In addition, they were able to form network-like structures on matrigel, which could be blocked by the DNA-based drug Defibrotide. This finding may be of great therapeutic relevance for tumour therapy.

Diagnostic criteria for hematopoietic stem cell transplant-associated microangiopathy: results of a consensus process by an International Working Group

BACKGROUND AND OBJECTIVES

There are no widely accepted criteria for the definition of hematopoietic stem cell transplant -associated microangiopathy (TAM). An International Working Group was formed to develop a consensus formulation of criteria for diagnosing clinically significant TAM.

DESIGN AND METHODS

The participants proposed a list of candidate criteria, selected those considered necessary, and ranked those considered optional to identify a core set of criteria. Three obligatory criteria and four optional criteria that ranked highest formed a core set. In an appropriateness panel process, the participants scored the diagnosis of 16 patient profiles as appropriate or not appropriate for TAM. Using the experts' ratings on the patient profiles as a gold standard, the sensitivity and specificity of 24 candidate definitions of the disorder developed from the core set of criteria were evaluated. A nominal group technique was used to facilitate consensus formation. The definition of TAM with the highest score formed the final

PROPOSAL

RESULTS

The Working Group proposes that the diagnosis of TAM requires fulfilment of all of the following criteria: (i) >4% schistocytes in blood; (ii) de novo, prolonged or progressive thrombocytopenia (platelet count <50 x 109/L or 50% or greater reduction from previous counts); (iii) sudden and persistent increase in lactate dehydrogenase concentration; (iv) decrease in hemoglobin concentration or increased transfusion requirement; and (v) decrease in serum haptoglobin. The sensitivity and specificity of this definition exceed 80%.

INTERPRETATION AND CONCLUSIONS

The Working Group recommends that the presented criteria of TAM be adopted in clinical use, especially in scientific trials.

Defibrotide: an endothelium protecting and stabilizing drug, has an anti-angiogenic potential in vitro and in vivo

Defibrotide (DF) is a polydisperse mixture of 90% single-stranded oligonucleotides with anti-thrombotic and anti-apoptotic functions. DF is used in the treatment of endothelial complications in the course of allogeneic stem cell transplantation. Recent preclinical evidence suggests that DF might also have anti-neoplastic properties. In the present study we hypothesized that DF might inhibit tumors via an anti-angiogenic effect. The anti-angiogenic potential of DF was tested in vitro using human microvascular endothelial cells forming vessel structures across a layer of dermal fibroblasts. Our results show that pharmacologic DF concentrations (100 mug/ml) significantly reduced vessel formation in this assay. Similarly, DF blocked sprouting from cultured rat aortic rings. In vivo, angiogenesis in a human gastric tumor (TMK1) implanted in dorsal skin-fold chambers (in nude mice) was inhibited by i.v. application of 450 mg/kg DF. Notably, due to its short half-life, DF was most effective when given on a daily basis. Although the precise mechanism of DF remains to be elucidated, initial Western blots show that DF reduces phosphorylation-activation of p70S6 kinase, which is a key target in the PI3K/Akt/mTOR signaling pathway linked to endothelial cell and pericyte proliferation and activation. However, in vitro data suggest that DF acts independently of vascular endothelial growth factor. Taken together, our data suggest that while DF is known for its endothelium-protecting function in SCT, it also inhibits formation of new blood vessels, and thus should be considered for further testing as an adjuvant anti-cancer agent, either alone, or in combination with other drugs.

Risk Factors and Severe Outcome in Thrombotic Microangiopathy After Allogeneic Hematopoietic Stem Cell Transplantation

BACKGROUND

Thrombotic microangiopathy (TMA) has been described as severe complication after hematopoietic stem cell transplantation (HSCT). The principal aim of this study was to focus the incidence and the outcome of TMA in the era of more complex HSCTs.

METHODS

We analyzed the role of some predicting factors for the incidence and the outcome of TMA after HSCT. We enrolled 539 consecutive patients (307 males, median age 31 years) undergoing HSCT from match or mismatch human leukocyte antigen family donor (314) or match/mismatch unrelated (195) and haploidentical donor (30) for malignant or nonmalignant diseases. TMA diagnosis was performed by homogeneous clinical and laboratory criteria.

RESULTS

Sixty-four of 539 patients presented TMA (11,87%) and the five-year cumulative incidence of TMA was 14% (HR=0.13). Fifty nine of 64 patients were affected by malignant and 5/64 by non-malignant diseases. On multivariate analysis, TMA occurrence was influenced by graft versus host disease >grade II (P=0.0001), donor type (P=0.029), gender (P=0.0233), total body irradiation based conditioning regimen (P=0.0041). Three factors for TMA outcome proved to be statistically significant by multivariate analysis: age (P=0.009), donor type (P=0.0187) and TMA index (P=0.029). The TMA mortality rate was 50%. The outcome was influenced by defibrotide (P=0.02 in univariate analysis).

CONCLUSIONS

The study underlines the possibility of finding out which patients are more prone to developing post-HSCT TMA, and identifies which risk factors are more frequently associated with a dismal outcome after TMA.

Defibrotide, a polydisperse mixture of single-stranded phosphodiester oligonucleotides with lifesaving activity in severe hepatic veno-occlusive disease: clinical outcomes and potential mechanisms of action

Veno-occlusive disease of the liver (VOD) remains a troubling and potentially fatal complication of high-dose chemotherapy and hematopoietic stem cell transplantation conditioning regimens. No effective therapy has been available for these patients to date, and the best supportive care measures remain woefully inadequate. Defibrotide (DF) (Gentium, S.p.A., Como, Italy), a polydisperse mixture of all the single-stranded phosphodiester oligodeoxyribonucleotides that can be obtained from the controlled depolymerization of porcine intestinal mucosal genomic DNA, seems to offer a safe and effective treatment for some patients suffering from severe VOD, a condition for which no accepted standard therapy currently exists. Early clinical studies evaluating the efficacy of DF for the treatment of severe VOD in patients undergoing hematopoietic stem cell transplantation have been very encouraging. Approximately 45% of the patients treated in multiple initial phase II clinical trials achieved a complete response at day +100, demonstrating normalization of serum bilirubin and resolution of the clinical syndrome. However, although multi-institutional, these represented single arm studies. A large, FDA-approved, pivotal, prospective, multi-institutional, global phase III trial of DF vs. historical controls (best available therapy) commenced in the first quarter of 2006 and should provide further validation of DF's efficacy. The drug seems to have few significant side effects, and almost all test subjects who have received this treatment have tolerated it well. Although the mechanism of action remains unclear, the drug exerts minimal systemic anticoagulant effects yet appears to induce numerous antithrombotic and profibrinolytic effects both in vitro and in vivo. It may function as an adenosine receptor agonist and causes increased concentrations of endogenous prostaglandins, which modulate thrombomodulin, platelets, and fibrinolysis. It also appears to block lipopolysaccharide (LPS)-induced tissue factor (TF) expression. However, despite the fact the DF is composed of oligonucleotides, its mechanism of action, which at the present time is unclear, is not related to Watson-Crick base pair-dependent downregulation of gene expression but is rather likely a result of its polyanionic nature.

Limiting the number of injected oocytes to three impairs ICSI outcomes in patients with nonobstructive azoospermia

BACKGROUND

Since March 2004, only a maximum of three oocytes were allowed to be subjected to ICSI at one time in Italy. A previous study failed to show an impact of this restriction on fresh embryo transfer outcomes. The objective of this study was to compare ICSI outcomes before and after this restriction in patients with nonobstructive azoospermia.

METHODS

Patients underwent testicular sperm extraction followed by ICSI. Biological (fertilization rate and the percentage of good-morphology zygotes and embryos) and clinical (clinical pregnancy and implantation rates) outcomes of the last 100 ICSI attempts before the restriction and outcomes of the first 100 ICSI attempts after the restriction were compared.

RESULTS

Despite comparable fertilization rates (58.8% versus 59.2%; P > 0.05), there was a significant decrease in the percentage of good-morphology zygotes (41.1% versus 88.4%; P < 0.05) and embryos (36.7% versus 74.0%; P < 0.05) in the cohort of embryos transferred, clinical pregnancy rate (22.7% versus 42.4%; P < 0.05) and cumulative pregnancy rate from fresh and frozen embryo transfers (22.7% versus 53.5%; P < 0.05) after the restriction.

CONCLUSION

The oocyte number restriction reduces dramatically the chance of achieving a clinical pregnancy in cases of nonobstructive azoospermia.

Strategies and clinical outcome of 250 cycles of Preimplantation Genetic Diagnosis for single gene disorders

BACKGROUND

We report on our experience with preimplantation genetic diagnosis (PGD) for single gene disorders (SGDs), from 1999 to 2004, describing strategies and overall clinical outcome of 250 cycles in 174 couples for 23 different genetic conditions.

METHODS

PGD cycles included 15 for autosomal dominant, 148 for autosomal recessive and 19 for X-linked SGDs. In addition, 68 cycles of PGD for SGDs were performed in combination with HLA matching. The strategy in each case used an initial multiplex PCR, followed by minisequencing to identify the mutation(s) combined with multiplex PCR for closely linked informative markers to increase accuracy. Linkage analysis, using intragenic and/or extragenic polymorphic microsatellite markers, was performed in cases where the disease-causing mutation(s) was unknown or undetectable.

RESULTS

In 250 PGD cycles, a total of 1961 cleavage stage embryos were biopsied. PCR was successful in 3409 out of 3149 (92.4%) biopsied blastomeres and a diagnosis was possible in 1849 (94.3%) embryos. Four hundred and twenty-seven embryos were transferred in 211 cycles, resulting in 71 pregnancies (33.6% per embryo transfer), including 15 biochemical pregnancies, six spontaneous miscarriages, two ectopic pregnancies, which were terminated, and nine pregnancies which are still ongoing. The remaining pregnancies were confirmed to be unaffected and went to term without complications, resulting in the birth of 35 healthy babies.

CONCLUSIONS

Minisequencing for mutation detection combined with multiplex fluorescence PCR for linkage analysis is an efficient, accurate and widely applicable strategy for PGD of SGDs. Our experience provides a further demonstration that PGD is an effective clinical tool and a useful option for many couples with a high risk of transmitting a genetic disease.

Oligotide, a defibrotide derivative, protects human microvascular endothelial cells against fludarabine-induced activation, damage and allogenicity

Fludarabine is a nonmyeloablative immunosuppressant increasingly used as a component of alternative reduced-intensity conditioning regimens prior to allogeneic stem cell transplantation (SCT). However, we have previously shown that 2-fluoroadenine 9-beta-D-arabinofuranoside (F-Ara) as the active metabolized form of fludarabine induces damage, activation and allogenicity in human microvascular endothelial cells (HMEC). We had also identified the pharmaceutic compound Defibrotide (DF), originally used in the treatment of veno-occlusive disease and thrombotic microangiopathy, as being protective against F-Ara-induced dysfunction of HMEC, importantly, without affecting the antileukemic effect of F-Ara. In the present report, we show that a recently developed derivative of DF, Oligotide, similarly downregulates F-Ara-induced activation and damage of HMEC as well as their antigenicity for allogeneic CD8+ T cells. In addition, Oligotide could also block F-Ara-mediated transendothelial migration of peripheral blood cells across the HMEC barrier. Taken together, these observations argue for a potential clinical use of both DF and Oligotide in pre transplant conditioning.

Clinical application of laser-assisted ICSI: a pilot study

Human oocyte survival after intracytoplasmic sperm injection (ICSI) can be compromised by abnormal oolemma breakage patterns during the penetration of the microinjection needle. We previously reported a case of repeated ICSI failures associated with abnormal oolemma breakage in which a substantial improvement and successful pregnancy were achieved by performing ICSI through a laser-drilled hole in the zona pellucida (laser-assisted ICSI). This study was undertaken to compare the efficacy of laser-assisted ICSI with that of conventional ICSI in patients whose oocytes present this particular feature. Oocytes treated by laser-assisted ICSI (n=140) survived better (97.9% versus 85.7%; P<0.05) and tended to form more two-pronucleated zygotes (78.6% versus 69.2%; P=0.07) and less zygotes with three or more pronuclei (2.8% versus 7.8%; P=0.06) as compared with sibling oocytes treated by conventional ICSI (n=140). These data show that laser-assisted ICSI is suitable for oocytes with propensity for sudden oolemma breakage during conventional ICSI. The reduction of oocyte damage with laser-assisted ICSI as compared to conventional ICSI may be useful in other clinical indications where only few oocytes are available or when the oocyte survival after ICSI can be supposed to be compromised.