A universal UHPLC-CAD platform for the quantification of polysaccharide antigens

Several glycoconjugate-based vaccines against bacterial infections have been developed and licensed for human use. Polysaccharide (PS) analysis and characterization is therefore critical to profile the composition of polysaccharide-based vaccines. For PS content quantification, the majority of Ultra High Performance Liquid Chromatography (UHPLC) methods rely on the detection of selective monosaccharides constituting the PS repeating unit, therefore requiring chemical cleavage and tailored development: only a few methods directly quantify the intact PS. The introduction of charged aerosol detector (CAD) technology has improved the response of polysaccharide analytes, offering greater sensitivity than other detector sources (e.g., ELSD). Herein, we report the development of a universal UHPLC-CAD method (UniQS) for the quantification and quality evaluation of polysaccharide antigens (e.g., Streptococcus Pneumoniae, Neisseria meningitidis and Staphylococcus aureus). This work laid the foundation for a universal UHPLC-CAD format that could play an important role in future vaccine research and development helping to reduce time, efforts, and costs.

AB1586-PARE MULTI-CENTER, RANDOMIZED, OPEN-LABEL, 2-ARM PARALLEL STUDY TO COMPARE THE PHARMACOKINETICS, SAFETY AND TOLERABILITY OF AVT02 ADMINISTERED SUBCUTANEOUSLY VIA PREFILLED SYRINGE OR AUTOINJECTOR IN HEALTHY ADULT VOLUNTEERS

Background

AVT02 is an investigational biosimilar to adalimumab. It is approved in Europe, Canada, and the UK. It is not approved by the US Food and Drug Administration (FDA).

Objectives

To evaluate the pharmacokinetic similarity of 100 mg/mL AVT02, an investigational biosimilar of adalimumab, when administered either via a pre-filled syringe, or with a newly developed autoinjector in healthy adult subjects.

Methods

This was a Phase 1, randomized, open-label, parallel-group study in which 207 healthy adult subjects were randomized in a 1:1 ratio to receive 100 mg/mL AVT02 either via a pre-filled syringe, or with an autoinjector, stratified by body weight. Subjects received a single subcutaneous 40 mg dose on Day 1. Pharmacokinetics, immunogenicity, local injection site reactions, and adverse events were assessed prior to, and up to 64 days after, study drug administration.

Results

The results observed supported the assessment of pharmacokinetic similarity of investigational AVT02 administered by pre-filled syringe or with an autoinjector. The 90% CIs for the ratios of geometric least square means for the primary pharmacokinetic parameters Cmax, AUC0-t, and AUC0-∞ were contained within prespecified margins 80% and 125%, based on an analysis of variance model with treatment as a fixed effect. The mean serum concentration-time profile of adalimumab by treatment group is shown in Figure 1.

Figure 1.

Mean Serum Concentration-Time Profile of Adalimumab by Treatment Group on Semilogarithmic Scale (Pharmacokinetic Population)

Binding anti-drug antibodies were detectable at the end of study visit on Day 64 in 100% and 97.0% of subjects in the pre-filled syringe administration and the autoinjector groups, respectively. Of those subjects positive for anti-drug antibodies, 85.7% and 86.5% further tested positive for neutralizing antibodies in the pre-filled syringe administration and autoinjector groups, respectively. The frequency of local administration site reactions was 11.8% overall and similar between treatment groups. The most frequently reported treatment-emergent adverse events in both treatment groups were under the SOC: Infections and infestations (56.0% in the AVT02-pre-filled syringe group and 45.2% in the AVT02-autoinjector group). The safety profiles were generally similar between treatment groups.

Conclusion

The results observed supported the assessment of pharmacokinetic similarity between the pre-filled syringe and autoinjector delivery systems after a single subcutaneous 40 mg dose. The autoinjector delivery system was generally well tolerated in healthy subjects, with a safety and immunogenicity profile similar to that observed with 100 mg/mL AVT02 administered using a pre-filled syringe.

ClinicalTrials.gov Identifier: NCT03983876

Disclosure of Interests

Christopher Wynne: None declared, Heimo Stroissnig Employee of: Alvotech, Roshan Dias Employee of: Alvotech, Joanna Sobierska Employee of: Alvotech, Eric Guenzi Employee of: Alvotech, Hendrik Otto Employee of: Alvotech, Abid Sattar Employee of: Alvotech, Halimu N. Haliduola Employee of: Alvotech, Elin Edwald Employee of: Alvotech, Fausto Berti Employee of: Alvotech

AB0350 ASSESSMENT OF REAL-LIFE PATIENT HANDLING EXPERIENCE OF AVT02 ADMINISTERED SUBCUTANEOUSLY VIA AUTOINJECTOR IN PATIENTS WITH MODERATE-TO-SEVERE ACTIVE RHEUMATOID ARTHRITIS: AN OPEN-LABEL, SINGLE-ARM CLINICAL TRIAL, THEN AN EXTENSION PHASE OF AVT02 ADMINISTERED WITH A PRE-FILLED SYRINGE (ALVOPAD-PEN)

Background

AVT02 is an investigational biosimilar to adalimumab. It is approved in Europe, Canada, and the UK. It is not approved by the US Food and Drug Administration (FDA).

Objectives

To assess the real-life patient handling of an autoinjector (AI) in adult patients with moderate-to-severe active rheumatoid arthritis (RA) who self-inject AVT02 subcutaneously (s.c.).

Methods

This open-label study enrolled 107 adalimumab-naïve subjects with moderate-to-severe active RA to self-inject AVT02 with the proposed AI 40 mg s.c. in Week 1, and every other week thereafter through Week 8. In an optional extension phase through Week 56, subjects were switched from AVT02 AI to pre-filled syringe and followed for safety and efficacy. The primary endpoint was the percentage of successful self-injections as reported by both the trial site and by subjects using standardized questionnaires at Week 8. Additional endpoints included ease of use and robustness of the AI at Week 8, and efficacy in RA, assessment of serum trough levels of AVT02, and detection of antidrug antibodies (ADA) throughout the study.

Results

The AI success rate was 100% as reported by both the trial site and by subjects. No handling events were noted through Week 8. Approximately 80% (78.1–84.9%) of subjects found the AI ‘very easy’ to use and, in general, less difficulty was reported as the study progressed. The first 110 AIs used were inspected for robustness and none showed any sign of damage or malfunction.

All subjects who completed Week 8 (n = 106) took part in and completed the optional extension phase through Week 56.

At Week 8, 49.1%, 5.7% and 0.9% subjects achieved ACR20, -50 and -70 responses, respectively. Improvement was also reported for the SDAI, DAS28 CRP and HAQ, with scores consistently decreasing through Week 8. In the extension phase, 70.8%, 47.2% and 13.2% subjects achieved ACR20, -50 and -70 responses at Week 56. Improvement was also reported for the SDAI, DAS28 CRP and HAQ, with scores consistently decreasing through Week 56.

From Baseline through Week 8 the mean serum concentrations of investigational AVT02 increased consistently at each visit, reaching a peak at Week 24. There was no significant difference in serum concentrations of AVT02 based on injection subsite (abdomen or thigh).

ADAs were detected in 65.1% of subjects through Week 8, reducing to 49.1% by Week 56. Of ADA-positive subjects, most were also positive for neutralizing antibodies through Week 8 (62.3%) increasing through Week 56 (90.4%). Subjects who were ADA-positive had lower serum concentrations of study drug compared with the overall population at Week 8 and Week 56 as expected.

There were no clinically relevant safety or tolerability issues. Overall, treatment-emergent adverse events reported in at least 5% of subjects at the PT level were anaemia and influenza (6 subjects [5.6%)] reported 6 events each), and no local ISRs were reported.

Conclusion

The fully successful self-injection with the AI in this study supported the use of the device while administering AVT02. Furthermore, subjects typically found the AI easy to use, with ease of use increasing as time progressed.

The ACR20, -50, and -70, SDAI, DAS28 CRP and HAQ results supported the use of AVT02 to treat adult patients with moderate-to-severe RA, with the treatment effect persisting beyond Week 8 and through Week 56.

The safety and immunogenicity profiles were as expected for adalimumab.

ClinicalTrials.gov Identifier: NCT04224194

Disclosure of Interests

Nemanja Damjanov: None declared, Heimo Stroissnig Employee of: Alvotech, Matjaz Steiger Employee of: Alvotech, Joanna Sobierska Employee of: Alvotech, Eric Guenzi Employee of: Alvotech, Hendrik Otto Employee of: Alvotech, Abid Sattar Employee of: Alvotech, Halimu N. Haliduola Employee of: Alvotech, Elin Edwald Employee of: Alvotech, Fausto Berti Employee of: Alvotech

The Use of Prophylactic Somatostatin Therapy Following Pancreaticoduodenectomy: A Meta-analysis of Randomised Controlled Trials

BACKGROUND

Prophylactic administration of somatostatin analogues (SA) to reduce the incidence of post-operative pancreatic fistula (POPF) remains contentious. This meta-analysis evaluated its impact on outcomes following pancreaticoduodenectomy (PD).

METHODS

The EMBASE, MEDLINE and Cochrane databases were searched for randomised controlled trials (RCTs) investigating prophylactic SA following PD. Comparative effects were summarised as odds ratio and weighted mean difference based on an intention to treat. Quantitative pooling of the effect sizes was derived using the random-effects model.

MAIN RESULTS

Twelve RCTs were included involving 1615 patients [SA-treated group (n = 820) and control group (n = 795)]. The SA used included somatostatin-14, pasireotide, vapreotide and octreotide. Pooling of the data showed no significant benefit of its use for the primary outcome measure of all grades of POPF, odds ratio (OR) 0.73 [95% confidence interval (CI), 0.51-1.05, p = 0.09] and clinically relevant POPF, OR 0.48 [95% CI, 0.22-1.06, p = 0.07]. There were no benefits in the secondary outcome measures of delayed gastric emptying, OR 0.98 [95% CI, 0.57-1.69, p = 0.94]; infected abdominal collections, OR 0.80 [95% CI, 0.44-1.43, p = 0.80]; reoperation rates, OR 1.24 [95% CI, 0.73-2.13, p = 0.42]; duration of hospital stay, - 0.23 [95% CI - .59 to 1.13, p = 0.74]; and mortality, 1.78 [95% CI, 0.94-3.39, p = 0.08].

CONCLUSION

SA did not improve the post-operative outcomes following PD, including reducing the incidence of POPF. The routine administration of SA cannot be recommended following PD.

Spontaneous symmetry breaking on ordered, racemic monolayers of achiral theophylline: formation of unichiral stripes on Au(111)

We report the observation of spontaneous chiral symmetry breaking within ordered, racemic monolayers of theophylline, manifesting itself as extended, nanoscale unichiral stripes at the interface between molecular domains. Theophylline is a xanthine derivative playing an important role in several biochemical processes. Molecular chirality is induced by adsorption on the Au(111) surface, resulting in extended domains with two different racemic, ordered structures, coexisting with a disordered phase. By combining low-temperature scanning tunneling microscopy (LT-STM) and ab initio density functional theory calculations, we first provide a detailed picture of the interactions within the ordered assemblies, and we uncover the origin of the distinct contrast features in STM images. Secondly, experiments reveal the existence of nanoscale stripes of unichiral molecules separating racemic domains of one of the two ordered phases, giving rise to a local enantiomeric imbalance. Systematic theoretical investigation of their structure and chiral composition confirm their unichirality, with the specific handedness related to the registry between the two ordered domains facing the stripes. These findings can open the way to new insights into the elusive mechanisms leading to local chiral imbalances in racemic systems, possibly at the origin of biomolecular homochirality, as well as suggest novel approaches for stereoselective heterogeneous catalysis.

Preclinical studies on new proteins as carrier for glycoconjugate vaccines

Glycoconjugate vaccines are made of carbohydrate antigens covalently bound to a carrier protein to enhance their immunogenicity. Among the different carrier proteins tested in preclinical and clinical studies, five have been used so far for licensed vaccines: Diphtheria and Tetanus toxoids, the non-toxic mutant of diphtheria toxin CRM197, the outer membrane protein complex of Neisseria meningitidis serogroup B and the Protein D derived from non-typeable Haemophilus influenzae. Availability of novel carriers might help to overcome immune interference in multi-valent vaccines containing several polysaccharide-conjugate antigens, and also to develop vaccines which target both protein as well saccharide epitopes of the same pathogen. Accordingly we have conducted a study to identify new potential carrier proteins. Twenty-eight proteins, derived from different bacteria, were conjugated to the model polysaccharide Laminarin and tested in mice for their ability in inducing antibodies against the carbohydrate antigen and eight of them were subsequently tested as carrier for serogroup meningococcal C oligosaccharides. Four out of these eight were able to elicit in mice satisfactory anti meningococcal serogroup C titers. Based on immunological evaluation, the Streptococcus pneumoniae protein spr96/2021 was successfully evaluated as carrier for serogroups A, C, W, Y and X meningococcal capsular saccharides.

Carrier priming with CRM 197 or diphtheria toxoid has a different impact on the immunogenicity of the respective glycoconjugates: biophysical and immunochemical interpretation

Glycoconjugate vaccines play an enormous role in preventing infectious diseases. The main carrier proteins used in commercial conjugate vaccines are the non-toxic mutant of diphtheria toxin (CRM197), diphtheria toxoid (DT) and tetanus toxoid (TT). Modern childhood routine vaccination schedules include the administration of several vaccines simultaneously or in close sequence, increasing the concern that the repeated exposure to conjugates based on these carrier proteins might interfere with the anti-polysaccharide response. Extending previous observations we show here that priming mice with CRM197 or DT does not suppress the response to the carbohydrate moiety of CRM197 meningococcal serogroup A (MenA) conjugates, while priming with DT can suppress the response to DT-MenA conjugates. To explain these findings we made use of biophysical and immunochemical techniques applied mainly to MenA conjugates. Differential scanning calorimetry and circular dichroism data revealed that the CRM197 structure was altered by the chemical conjugation, while DT and the formaldehyde-treated form of CRM197 were less impacted, depending on the degree of glycosylation. Investigating the binding and avidity properties of IgGs induced in mice by non-conjugated carriers, we found that CRM197 induced low levels of anti-carrier antibodies, with decreased avidity for its MenA conjugates and poor binding to DT and respective MenA conjugates. In contrast, DT induced high antibody titers able to bind with comparable avidity both the protein and its conjugates but showing very low avidity for CRM197 and related conjugates. The low intrinsic immunogenicity of CRM197 as compared to DT, the structural modifications induced by glycoconjugation and detoxification processes, resulting in conformational changes in CRM197 and DT epitopes with consequent alteration of the antibody recognition and avidity, might explain the different behavior of CRM197 and DT in a carrier priming context.

Meningococcal X polysaccharide quantification by high-performance anion-exchange chromatography using synthetic N-acetylglucosamine-4-phosphate as standard

A method for meningococcal X (MenX) polysaccharide quantification by high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) is described. The polysaccharide is hydrolyzed by strong acidic treatment, and the peak of glucosamine-4-phosphate (4P-GlcN) is detected and measured after chromatography. In the selected conditions of hydrolysis, 4P-GlcN is the prevalent species formed, with GlcN detected for less than 5% in moles. As standard for the analysis, the monomeric unit of MenX polysaccharide, N-acetylglucosamine-4-phosphate (4P-GlcNAc), was used. This method for MenX quantification is highly selective and sensitive, and it constitutes an important analytical tool for the development of a conjugate vaccine against MenX.

A scalable method for O-antigen purification applied to various Salmonella serovars

The surface lipopolysaccharide of gram-negative bacteria is both a virulence factor and a B cell antigen. Antibodies against O-antigen of lipopolysaccharide may confer protection against infection, and O-antigen conjugates have been designed against multiple pathogens. Here, we describe a simplified methodology for extraction and purification of the O-antigen core portion of Salmonella lipopolysaccharide, suitable for large-scale production. Lipopolysaccharide extraction and delipidation are performed by acetic acid hydrolysis of whole bacterial culture and can take place directly in a bioreactor, without previous isolation and inactivation of bacteria. Further O-antigen core purification consists of rapid filtration and precipitation steps, without using enzymes or hazardous chemicals. The process was successfully applied to various Salmonella enterica serovars (Paratyphi A, Typhimurium, and Enteritidis), obtaining good yields of high-quality material, suitable for conjugate vaccine preparations.

Sandwich ELISA assay for the quantitation of palytoxin and its analogs in natural samples

Palytoxins are potent marine biotoxins that have recently become endemic to the Mediterranean Sea, and are becoming more frequently associated with seafood. Due to their high toxicity, suitable methods to quantify palytoxins are needed. Thus, we developed an indirect sandwich ELISA for palytoxin and 42-hydroxy-palytoxin. An intralaboratory study demonstrated sensitivity (limit of detection, LOD = 1.1 ng/mL; limit of quantitation, LOQ = 2.2 ng/mL), accuracy (bias of 2.1%), repeatability (RSDr = 6% and 9% for intra- and interassay variability, respectively) and specificity: other common marine toxins (okadaic acid, domoic acid, saxitoxin, brevetoxin-3, and yessotoxin) do not cross-react in this assay. It performed well in three different matrices: observed LOQs were 11.0, 9.6, and 2.4 ng/mL for mussel extracts, algal net samples and seawater, respectively, with good accuracy and precision. The LOQ in seafood is 11 μg palytoxin/kg mussel meat, lower than that of the most common detection technique, LC-MS/MS.

Relative stability of meningococcal serogroup A and X polysaccharides

Prior to the introduction of the MenAfriVac™ serogroup A glycoconjugate vaccine in September 2010, serogroup A was the major epidemic disease-causing meningococcal serogroup in the African meningitis belt. However, recently serogroup X meningococcal (MenX) disease has received increased attention because of outbreaks recorded in this region, with increased endemic levels of MenX disease over the past 2 years. Whereas polysaccharide-protein conjugate vaccines against meningococcal serogroups A, C, W and Y (MenA, MenC, MenW, MenY) are on the market, a vaccine able to protect against MenX has never been achieved. The structure of serogroup A, C, W and Y meningococcal polysaccharides has been already fully elucidated by NMR. MenX capsular polysaccharide (MenX CPS) structure is also documented but fewer characterization data have been published. We have applied here (1)H NMR, (31)P NMR and HPLC to evaluate the stability of MenX CPS in aqueous solution as compared to MenA capsular polysaccharide (MenA CPS). The stability study demonstrated that MenA CPS is more susceptible to hydrolytic degradation than MenX CPS. The different stereochemistry of the N-acetyl group at position C(2) of mannosamine (MenA CPS) and glucosamine (MenX CPS) respectively might play a fundamental role in this susceptibility to polysaccharide chain degradation. The satisfactory stability of MenX CPS predicts the possibility that a stable fully-liquid MenX polysaccharide or glycoconjugate vaccine could be developed.

Internal auditory canal metastasis

Metastasis of the inner auditory canal is a really rare event. Clinically, it usually presents with rapid worsening cranial nerve palsy. Authors present a review of the literature reporting clinical features, radiological findings, intraoperative aspects of an illustrative case. A 56-year-old female patient presented with a peripheral facial nerve palsy. MRI showed two left p-fossa tumors whose one into the inner canal. Rapid worsening of facial damage despite corticosteroid treatment and the possibility to remove both tumors in the same surgical step suggested authors to operated on the patient. Intraoperatively, inner canal tumor looked totally involving the VII-VIII nerve complex so surgical extirpation was only partially feasible. Posterior wall drilling of the meatus was performed which improved facial palsy. Leptomeningeal spinal seeding occurred and spinal irradiation was performed. The case highlights the importance of maintaining a high degree of awareness of the auditory canal metastasis in patients with a previous history of malignancy who develop a rapid progressive peripheral VII nerve palsy. Furthermore, our case and literature data suggest that inner canal metastasis is a distinct entity from temporal bone and ponto-cerebellar angle metastasis on the base of the peculiarity of clinical features, prognosis, therapeutic strategies. In fact, inner canal metastases usually arise in patients apparently cured, and they imply a better prognosis even if with an higher risk of leptomeningeal seeding. Moreover, surgery rarely allows the removal of the lesion, also if symptoms relief may be achieved, as in our case.

The hydrogen sulphide-releasing derivative of diclofenac protects against ischaemia-reperfusion injury in the isolated rabbit heart

BACKGROUND AND PURPOSE

Hydrogen sulphide (H(2)S) is an endogenous gaseous mediator active in the multilevel regulation of pathophysiological functions in mammalian cardiovascular tissues.

EXPERIMENTAL APPROACH

This study investigated the pharmacological activity of a new H(2)S-releasing derivative of diclofenac, S-diclofenac (2-[(2,6-dichlorophenyl)amino]benzeneacetic acid 4-(3H-1,2-dithiole-3-thione-5-yl)-phenyl ester) in the isolated rabbit heart submitted to low-flow ischaemia-reperfusion damage.

KEY RESULTS

S-diclofenac (3, 10 and 30 microM), despite inhibiting prostacyclin generation by cardiac tissues, achieved dose-dependent normalization of coronary perfusion pressure, reducing left ventricular contracture during ischaemia and improving left ventricular developed pressure and +/-dP/dt(max) at reperfusion. Creatine kinase and lactate dehydrogenase activities in heart perfusates were significantly reduced during reperfusion. These effects were accompanied by substantial release of reduced glutathione (GSH), indicating that the H(2)S moiety may have up-regulated cysteine transport. The anti-ischaemic activities of S-diclofenac and the H(2)S-donor sodium hydro sulphide (NaHS) were partially prevented by the K(ATP) channel antagonist glibenclamide, suggesting a mechanism similar to H(2)S-induced cardioprotection in metabolic ischaemic preconditioning. Perfusion with the nitric oxide (NO) synthase inhibitor N(G)-monomethyl-L-arginine worsened the myocardial ischaemia-reperfusion damage, but this was dose-dependently prevented by S-diclofenac and NaHS, suggesting that the released H(2)S may have overcome NO deficiency.

CONCLUSION AND IMPLICATIONS

These data show that S-diclofenac had marked anti-ischaemic activity in ischaemic-reperfused rabbit hearts despite inhibition of prostaglandin generation. Increased GSH formation leading to activation of K(ATP) channels may have contributed to this beneficial effect. The pharmacological profile of S-diclofenac and its anti-inflammatory activity, with diminished gastrointestinal side effects, offer therapeutic applications in cardiovascular disease.

Endothelium-mediated modulation of ergoreflex and improvement in exercise ventilation by acute sildenafil in heart failure patients

Reflex neural oversignaling sensitive to muscle by-products (ergoreflex) causes exercise hyperventilation in heart failure (HF). We probed whether an improved endothelial function with sildenafil intake may prevent this effect. In 16 chronic heart failure patients and 16 normal subjects, before and after sildenafil intake (50 mg) or placebo, we measured ergoreflex, flow-mediated brachial artery dilation (FMD, an index of endothelial function), and, during maximal exercise, the slope of ventilation to carbon dioxide production (VE/VCO2, an index of ventilatory efficiency), the ratio of changes in O2 uptake (VO2) versus work rate (WR) (deltaVO2/deltaWR, an index of aerobic efficiency). After sildenafil intake, patients, unlike controls, showed a significant decrease in ergoreflex and VE/VCO2 slope and an increase in FMD and deltaVO2/deltaWR. Ergoreflex changes with sildenafil intake correlated with those in FMD and VE/VCO2. Phosphodiesterase-5 inhibition, by improving endothelial activity and muscle perfusion, modulates signaling and improves ventilatory and aerobic efficiencies, potentially indicating a novel pathway in the HF therapeutic management.

Sildenafil reduces L-NAME-induced severe hypertension and worsening of myocardial ischaemia-reperfusion damage in the rat

BACKGROUND AND PURPOSE

Phosphodiesterase-5 inhibitors are beneficial in pulmonary hypertension and congestive heart failure, the two conditions associated with coronary heart disease and ischaemia. We investigated whether sildenafil counteracts the cardiovascular alterations induced by N -nitro-L-arginine methyl ester (L-NAME) in the rat.

EXPERIMENTAL APPROACH

Sildenafil was given orally to rats at doses of 0.37, 0.75 or 1.5 mg kg-1day-1 for four weeks, either alone or with L-NAME (35-40 mg kg-1 day-1 in the drinking water). Systolic blood pressure and urinary parameters (6-keto-prostaglandin F1alpha, thromboxane B2, 8-isoprostane-prostaglandin F2 and nitrite/nitrate) were measured in conscious rats. Isolated hearts were subjected to low flow ischaemia-reperfusion, and myocardial levels of guanosine 3', 5'cyclic monophosphate (cGMP) were determined. Endothelial vascular dysfunction was examined in aortic rings.

KEY RESULTS

Sildenafil dose-dependently prevented the rise in systolic blood pressure in L-NAME-treated rats. This activity was associated with a normalization of urinary 8-isoprostane-prostaglandin F2alpha and other biochemical parameters. In perfused hearts, the post-ischaemic ventricular dysfunction was worse in preparations from L-NAME-treated rats than in controls. Sildenafil dose-dependently reduced this effect, and creatine kinase and lactate dehydrogenase release were lower too. cGMP levels, which were low in myocardial tissue from L-NAME-treated rats, were restored by sildenafil. In noradrenaline-precontracted aortic rings from L-NAME-treated rats acetylcholine lost its vasorelaxant effect, and sildenafil restored it.

CONCLUSION AND IMPLICATIONS

In a rat model of chronic nitric oxide deprivation, where hypertension and aggravation of post-ischaemic ventricular dysfunction are associated with loss of vascular endothelium-relaxant function, sildenafil provided significant cardiovascular protection, primarily by maintaining tissue cGMP levels.

Temozolomide (TMZ) 3 weeks on/1 week off in the treatment of progressive low grade gliomas: A phase II GICNO study

1514

Background: Encouraging results have been obtained inlow grade glioma (LGG) patients (pts) following TMZ therapy at the standard schedule of 200 mg/m2 for five-days every 28 days. A continuous dose TMZ schedule leads to DNA repair enzyme AGAT level depletion in tumor cells. By removing TMZ-produced methyl adducts, AGAT contributes to the development of resistance to alkylating agents. Methods: Pts with a diagnosis of LGG received TMZ 75 mg/m2/d for 21 days every 28 days at clinical or radiological progression. MiniMax Simon’s design with P0=0.2, P1=0.4, α=0.1, β=0.1 was used and a sample size of 36 pts was planned. The primary end-point was to assess the response rate (RR=CR+PR), and the secondary end-point to investigate the correlations between 1p/19q deletions by FISH and MGMT promoter methylation by methylation specific PCR (MSP). Results: 22 oligodendroglioma (O), 4 oligoastrocytoma (OA) and 10 astrocytoma pts (A) were enrolled (median age of pts 47 years, range 24–69 years; median KPS 90, range 50–100). Eleven pts were pre-treated with radiotherapy; 5 (13.5%) had enhancing lesion at MRI scan. RR was 30.5% (11 PR), all RR being obtained in pts with non-enhancing lesions; 20 pts (55.5%) had disease stabilization; 8/11 responders were assessable for 1p/19 q deletions and, of these, 6 pts (75%) had combined 1p/19q deletion. Median PFS was 17.4 months (interquartile ranges, 9.3–25). PFS at 1 year was 73% (SE 8%). Preliminary data on molecular assessment are: 29 pts were assessable for 1p and 19q deletions, both being present in 19 pts (65.5%). 1p/19 q loss was significantly greater in pts with O/OA than A (p=0.01). Of 11 assessable pts, 7 (63.6%) presented MGMT promoter gene methylation and all 7 pts presented 1p and 19q deletions (p=0.03). Grade 3 lymphopenia was observed in 4 pts (11.1%) and 1 patient had G2 reversible renal toxicity. Conclusion: TMZ for 21 days every 28 is an active and well tolerated regimen in pts with LGG. The analysis to verify any correlation between molecular markers and clinical outcome is ongoing.

[Table: see text]

A mixture of isothiocyanates induces cyclin B1- and p53-mediated cell-cycle arrest and apoptosis of human T lymphoblastoid cells

As with other candidate chemopreventive agents, most of our knowledge on the biological effects of isothiocyanates (the many sulfur-containing metabolites found in cruciferous vegetables) comes from studies of single natural or synthetic compounds. To investigate whether the biological/chemopreventive effects of administration of single isothiocyanates can differ from those of a mixture of isothiocyanates, we tested the effects of a mixture of four different isothiocyanates on cell-cycle progression and apoptosis in human T leukemia Jurkat cells, and identified some of the molecular pathways triggered by the mixture. The mixture affected critical points of the cell cycle via modulation of the expression of cyclin B1. Moreover, it induced apoptosis, mediated by an increase in p53 and bax (expression of bcl-2 was unaffected). Comparison of the data with those previously obtained with the single isothiocyanates under identical experimental conditions provides evidence that the quantitative effects of a single, specific isothiocyanate can be significantly different from those of an isothiocyanate mixture at realistic doses.

How effective is BCNU in recurrent glioblastoma in the modern era?: A phase II trial

BACKGROUND

The initial studies on nitrosoureas were performed >30 years ago. These drugs remain the standard chemotherapy for glioblastoma. However, because the criteria used to evaluate the activity of nitrosoureas in a neuro-oncologic setting have changed, new data on their activity are needed.

METHODS

The authors conducted a phase II study on 40 patients with recurrent glioblastoma following surgery and standard radiotherapy. They analyzed progression-free survival at 6 months (PFS-6), time to progression (TTP), response rate, and toxicity. Patients were treated with 80 mg/m2 carmustine on days 1 to 3, every 8 weeks for a maximum of six cycles.

RESULTS

Median TTP was 13.3 weeks (95% CI, 10.26 to 16.86 weeks), and PFS-6 was 17.5% (95% CI, 8.9 to 34.3). Response to chemotherapy, age < or =40 years, and performance status > or =90 were significant prognostic factors for TTP; however, with multivariate analysis, only response to chemotherapy was significant. The major side effects were reversible hematologic and long-lasting hepatic and pulmonary toxicity.

CONCLUSION

The activity of this BCNU regimen is comparable with that reported in the past and with the newest therapies, such as temozolomide. However, BCNU toxicity is high and recovery is slow, thus compromising the administration of further drugs in patients with progressive disease.

Procyanidins from Vitis vinifera seeds display cardioprotection in an experimental model of ischemia-reperfusion damage

Since the early 1970s, increasing evidence has suggested that the consumption of moderate amounts of alcohol is inversely correlated with mortality from myocardial infarction. There is also some evidence that the protective effects of wine might be more pronounced than those of other alcoholic beverages. These observations prompted us to investigate the cardioprotective activity of Vitis vinifera seeds in experimental ischemia-reperfusion injury. An isolated rabbit heart preparation paced electrically was used to evaluate the effects of a highly purified, high molecular weight fraction of oligomeric procyanidins isolated from Vitis vinifera seeds on myocardial reperfusion injury after 40 min of low-flow (1 ml/min) ischemia. Infusion of the heart with 100 or 200 microg/ml procyanidins dose-dependently reduced left ventricular end-diastolic pressure during ischemia, decreased coronary perfusion pressure, improved cardiac mechanical performance upon reperfusion, increased the release of 6-Keto-prostaglandin F1alpha into the perfusate in both the preischemic and the reperfusion periods and suppressed rhythm irregularity. Procyanidins dose-dependently relaxed human internal mammary aortic (IMA) rings (with intact endothelium) precontracted with norepinephrine. This effect was completely abolished in IMA-rings without functional endothelium or when this vascular tissue was pretreated with nitric oxide synthase inhibitor (NG-monomethyl-L-arginine) or with guanylate cyclase inhibitor (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one). In conclusion, these results indicate that procyanidins could be of therapeutical potential in cardiovascular diseases. However, further investigations are required for a better definition of the mode of action of these oligomers.

Moexipril and quinapril inhibition of tissue angiotensin-converting enzyme activity in the rat: evidence for direct effects in heart, lung and kidney and stimulation of prostacyclin generation

The activation of angiotensin converting enzyme (ACE) may contribute to the development of vascular and myocardial structural changes. The level of ACE is stable in human plasma, and only limited data are available on its regulation at the tissue level. The aim of this study was to characterize the effects of two ACE inhibitors, moexipril and quinapril on tissue ACE activity. Adult male rats were treated intragastrically once daily for 6 days either with 2 mg/kg moexipril or quinapril. After single treatment, moexipril and quinapril effectively inhibited ACE activity in plasma and slightly in heart and aorta, whereas after 6 days of treatment they inhibited ACE activity in plasma (87% and 94%, respectively), lung (92% and 93%), myocardium (26% and 23%), kidney (21% and 20%), and aorta (39% and 40%), but not in skeletal muscle. Interestingly, the two ACE-inhibitors also induced a significant increase in cardiac homogenates of 6-keto-PGF1alpha levels, an important index of PGI2 generation. To test whether the reduced effects of ACE inhibitors in heart and kidney were caused by a limited availability of the drugs, 100 microl of lung, heart and kidney homogenates from control rats were incubated in vitro with moexipril and quinapril immediately before assay. Both drugs were more effective in lung than heart and kidney homogenates, with inhibition values superimposable to those obtained in vivo. These results clearly indicate that inhibition of tissue ACE activity does not depend primarily on the availability of ACE inhibitors in each organ.

Cyclin D3 and p53 mediate sulforaphane-induced cell cycle delay and apoptosis in non-transformed human T lymphocytes

Despite experimental evidence that sulforaphane can exert chemopreventive effects, whether these effects are specific for neoplastic cells is not known. Following our previous demonstration that sulforaphane induces cell cycle arrest and apoptosis in human T lymphoblastoid Jurkat leukemia cells and increases p53 and bax protein expression, we tested sulforaphane on non-transformed phytohemagglutinin-stimulated human lymphocytes. Here, we demonstrate that sulforaphane arrested cell cycle progression in G, phase, through a decrease in the protein expression of cyclin D3. Moreover, sulforaphane induced apoptosis (and also necrosis), mediated by an increase in the expression of p53. These findings suggest that sulforaphane is a growth modulator for T cells. Our in vitro evidence that sulforaphane is active and even cytotoxic in normal as well as transformed lymphocytes raises important questions regarding its suitability for cancer chemoprevention.

Synthesis of N-terminal substituted anthranilic acid dimer derivatives for evaluation on CCK receptors

A series of new N-substituted anthranilic acid dimer derivatives having a C-terminal Phe residue was synthesized and evaluated for their affinity for CCK receptors. These compounds resulted from a blended approach based firstly on the use of an alternative substructure embedded within asperlicin and secondly on the derivatization of this template with substituents chosen considering the C-terminal primary structure of the endogenous ligand. Although these compounds exhibited a regnylogical-type organization similar to that of CCK-4, they are characterized by about 1000-fold greater affinity for CCK-A receptor than the C-terminal tetrapeptide.