88 Prevalence Of SARS-COVID-19 Serum Igg Antibodies Amongst Staff on An Acute Surgical Unit

Background

The United Kingdom now has one of the highest death rates from COVID 19, with over 40,000 deaths (1). It has been posited that the identification of care workers with immunity or increased resistance could be important in developing future strategies.

Method

This was a retrospectively conducted survey of general surgical staff at a tertiary surgical unit.

Results

We surveyed 215 staff that had undergone antibody testing. Of the 175/215 who reported contact with COVID-19 positive patients, 6/215 had a positive PCR result and 15/215 reported a positive antibody test. Only 3/6 that had a positive PCR test demonstrated antibodies.

Conclusions

Our “immunity” rate of 7% is extremely low and is concerning especially in respect of the anticipated “herd immunity” which would mitigate many of the issues presently being confronted and it is likely to be many months at least before this makes realistic contribution. Continued testing for the presence of COVID-19 antibodies will contribute to crucial seroprevalence data that can be used by public health bodies whose advice will necessarily evolve as increasing data sets become available.

A phase 1/1b study of PUR1900, an inhaled formulation of itraconazole, in healthy volunteers and asthmatics to study safety, tolerability and pharmacokinetics

AIMS

Oral itraconazole has variable pharmacokinetics and risks of adverse events associated with high plasma exposure. An inhalation formulation of itraconazole (PUR1900) is being developed to treat allergic bronchopulmonary aspergillosis, an allergic inflammatory disease occurring in asthmatics and patients with cystic fibrosis.

METHODS

A 3-part, open-label Phase 1 study was conducted to evaluate safety, tolerability and pharmacokinetics of PUR1900. Healthy volunteers (n = 5-6/cohort) received either single (Part 1) or multiple (Part 2) ascending doses of PUR1900 for up to 14 days. In Part 3 stable, adult asthmatics received a single dose of 20 mg PUR1900 or 200 mg of oral Sporanox (itraconazole oral solution) in a 2-period randomized cross-over design. Itraconazole plasma and sputum concentrations were evaluated.

RESULTS

None of the adverse events considered as at least possibly related to study treatment were moderate or severe, and none were classed as serious. The most common was the infrequent occurrence of mild cough. Itraconazole plasma exposure increased with increasing doses of PUR1900. After 14 days, PUR1900 resulted in plasma exposure (area under the concentration-time curve up to 24 h) 106- to 400-fold lower across doses tested (10-35 mg) than steady-state exposure reported for oral Sporanox 200 mg. In asthmatics, PUR1900 geometric mean maximum sputum concentrations were 70-fold higher and geometric mean plasma concentrations were 66-fold lower than with oral Sporanox.

CONCLUSION

PUR1900 was safe and well-tolerated under the study conditions. Compared to oral dosing, PUR1900 achieved higher lung and lower plasma exposure. The pharmacokinetic profile of PUR1900 suggests the potential to improve upon the efficacy and safety profile observed with oral itraconazole.

A Phase 1b Trial to Assess the Pharmacokinetics of Ezutromid in Pediatric Duchenne Muscular Dystrophy Patients on a Balanced Diet

Ezutromid (SMT C1100) is a small-molecule utrophin modulator that was developed to treat Duchenne muscular dystrophy (DMD). Previous clinical trials of this agent revealed lower exposure in DMD patients compared with healthy volunteers, which may reflect differences in diet. This study evaluated the pharmacokinetics of ezutromid in patients with DMD who followed a balanced diet. This was a multicenter, double-blind, placebo-controlled, ascending single and multiple oral dose study. Twelve pediatric patients were randomly allocated to 1 of 3 treatment sequences within which were 3 treatment periods of 2 weeks each. Each patient received, in a dose-escalating fashion, 1250 mg and 2500 mg twice daily (BID) of ezutromid administered orally as a microfluidized suspension (F3) with placebo in the other treatment period. Throughout the study, patients followed a balanced diet including recommended proportions of major food groups and administration of drug accompanied with 100 mL of full-fat milk. This approach improved the absorption of ezutromid, resulting in higher systemic exposure, with considerable variability in exposure between patients at each dose level. Single and multiple oral doses of 1250 mg and 2500 mg BID were considered safe and well tolerated. No severe or serious adverse events and no study discontinuations due to adverse events were reported. This study provides assurance that, with the formulation tested (F3) and instructions regarding food (balanced diet and whole-fat milk), 2500 mg BID of ezutromid achieves plasma concentrations that, based on preclinical studies, should be able to modulate utrophin expression in future clinical trials.

Efficacy and safety of the histamine H4 receptor antagonist ZPL-3893787 in patients with atopic dermatitis

BACKGROUND

H₄ receptor antagonists are potential novel treatments for inflammatory skin diseases, including atopic dermatitis (AD).

OBJECTIVE

We sought to study the efficacy and safety of ZPL-3893787 (a selective H₄ receptor antagonist) in patients with moderate-to-severe AD.

METHODS

A randomized, double-blind, placebo-controlled, parallel-group study was conducted to evaluate ZPL-3893787 (30 mg) once-daily oral therapy in adults with moderate-to-severe AD. Patients were randomized (2:1) to ZPL-3893787 (n = 65) or placebo (n = 33) for 8 weeks. Patients had a history of AD for more than 12 months, Eczema Area and Severity Index (EASI) scores of 12 or greater and 48 or less, Investigator's Global Assessment (IGA) scores of 3 or greater, pruritus scores of 5 or greater (0- to 10-point scale), and AD on 10% or greater of body surface area. Efficacy parameters included EASI, IGA, SCORAD, and pruritus assessment.

RESULTS

Treatment with oral ZPL-3893787 showed a 50% reduction in EASI score compared with 27% for placebo. The placebo-adjusted reduction in EASI score at week 8 was 5.1 (1-sided P = .01). Clear or almost-clear IGA scores were 18.5% with ZPL-3893787 versus 9.1% with placebo. SCORAD scores exhibited 41% reduction with ZPL-3893787 versus 26% with placebo (placebo-adjusted reduction of 10.0, P = .004). There was a 3-point reduction (scale, 1-10) in pruritus with ZPL-3893787, but there was a similar reduction with placebo, resulting in a nonsignificant difference (P = .249). Patient-reported pruritus subscores obtained from SCORAD were reduced with ZPL-3893787 compared with placebo at week 8 (nonsignificant). ZPL-3893787 was well tolerated.

CONCLUSION

For the first time, these results showed that ZPL-3893787 improved inflammatory skin lesions in patients with AD, confirming H₄ receptor antagonism as a novel therapeutic option.

Safety, Tolerability, and Pharmacokinetics of SMT C1100, a 2-Arylbenzoxazole Utrophin Modulator, following Single- and Multiple-Dose Administration to Pediatric Patients with Duchenne Muscular Dystrophy

Purpose

SMT C1100 is a utrophin modulator being evaluated as a treatment for Duchenne muscular dystrophy (DMD). This study, the first in pediatric DMD patients, reports the safety, tolerability and PK parameters of single and multiple doses of SMT C1100, as well as analyze potential biomarkers of muscle damage.

Methods

This multicenter, Phase 1 study enrolled 12 patients, divided equally into three groups (A–C). Group A were given 50 mg/kg on Days 1 and 11, and 50 mg/kg bid on Days 2 to 10. Group B and C received 100 mg/kg on Days 1 and 11; Group B and Group C were given 100 mg/kg bid and 100 mg/kg tid, respectively, on Days 2 to 10. A safety review was performed on all patients following the single dose and there was at least 2 weeks between each dose escalation, for safety and PK review. Adverse events (AEs) were monitored throughout the study.

Results

Most patients experienced mild AEs and there were no serious AEs. Two patients required analgesia for pain (headache, ear pain and toothache). One patient experienced moderate psychiatric AEs (abnormal behaviour and mood swings). Plasma concentrations of SMT C1100 at Days 1 and 11 indicated a high degree of patient variability regardless of dose. Unexpectedly the SMT C1100 levels were significantly lower than similar doses administered to healthy volunteers in an earlier clinical study. In general, individual baseline changes of creatine phosphokinase, alanine aminotransferase, aspartate aminotransferase levels fell with SMT C1100 dosing.

Conclusions

SMT C1100 was well tolerated in pediatric DMD patients.

Trial Registration

ClinicalTrials.gov NCT02383511

P2X3 receptor antagonist (AF-219) in refractory chronic cough: a randomised, double-blind, placebo-controlled phase 2 study

BACKGROUND

Preclinical studies suggest that P2X3 receptors are expressed by airway vagal afferent nerves and contribute to the hypersensitisation of sensory neurons. P2X3 receptors could mediate sensitisation of the cough reflex, leading to chronic cough. We aimed to investigate the efficacy of a first-in-class oral P2X3 antagonist, AF-219, to reduce cough frequency in patients with refractory chronic cough.

METHODS

We did a double-blind, placebo-controlled, two-period, crossover study at one UK centre. With a computer-generated sequence, we randomly assigned patients with refractory chronic cough to AF-219, 600 mg twice a day, or to placebo (1:1), and then, after a 2 week washout, assigned patients to receive the other treatment. Patients, health-care providers, and investigators were masked to sequence assignment. We assessed daytime cough frequency (primary endpoint) at baseline and after 2 weeks of treatment using 24 h ambulatory cough recordings. The primary analysis used a mixed effects model with the intention-to-treat population. This study was registered at ClinicalTrials.gov, number NCT01432730.

FINDINGS

Of 34 individuals assessed between Sept 22, 2011, and Nov 29, 2012, we randomly assigned 24 patients (mean age 54·5 years; SD 11·1). In the observed case analysis, cough frequency was reduced by 75% when patients were allocated to AF-219 compared when allocated to placebo (p=0·0003). Daytime cough frequency fell from a mean 37 coughs per h (SD 32) to 11 (8) coughs per h after AF-219 treatment versus 65 (163) coughs per h to 44 (51) coughs per h after placebo. Six patients withdrew before the end of the study because of taste disturbances, which were reported by all patients taking AF-219.

INTERPRETATION

P2X3 receptors seem to have a key role in mediation of cough neuronal hypersensitivity. Antagonists of P2X3 receptors such as AF-219 are a promising new group of antitussives.

FUNDING

Afferent Pharmaceuticals.

Effects of multiple doses of voriconazole on the vision of healthy volunteers: a double-blind, placebo-controlled study

PURPOSE

To investigate the effects, and their reversibility, of multiple oral voriconazole doses on a variety of visual tests in healthy male volunteers.

METHODS

Single-center, double-blind, randomized, placebo-controlled, parallel-group study in 36 volunteers who received voriconazole (n=18, 400 mg every 12 h on day 1, then 300 mg every 12 h for 27.5 days) or matched placebo (n=18). Electroretinograms (ERGs) and ophthalmological examinations were performed at screening, throughout the study and at follow-up.

RESULTS

Fifteen (83.3%) volunteers treated with voriconazole experienced ≥1 treatment-related visual adverse events (AEs); these included enhanced visual perceptions, blurred vision, color vision changes and photophobia. No serious AEs were reported. Voriconazole reduced from baseline scotopic maximal a- and b-wave amplitude, shortened implicit time and decreased oscillatory potential amplitude compared with placebo. Under photopic conditions, the 30-Hz flicker response amplitude was significantly reduced and was accompanied by a slight but nonsignificant prolongation of peak time. These effects did not progress in degree over the treatment period, and mean changes from baseline in ERG parameters were similar to placebo by day 43 (14 days after end of treatment). In the first week, color vision discrimination was impaired in the tritan axis, although this resolved by end of treatment and was similar to placebo by day 43. Mean deviation in the static visual field indicated increased sensitivity following voriconazole treatment, correlating with decreased amplitude in conjunction with shortened implicit time.

CONCLUSIONS

Effects of voriconazole on altered visual perception, ERG, color vision and static visual field thresholds are nonprogressive over a treatment period and reversible. It is hypothesized that voriconazole has a pharmacological effect on rod and cone pathways including a possible mechanism of disinhibition that reversibly puts the retina in a more light-adapted state and leads to increased relative contrast sensitivity.

Pharmacokinetic interactions between lersivirine and zidovudine, tenofovir disoproxil fumarate/emtricitabine and abacavir/lamivudine

BACKGROUND

To investigate pharmacokinetic interactions associated with coadministration of lersivirine with zidovudine, tenofovir disoproxil fumarate (DF)/emtricitabine (Truvada(®)) or abacavir/lamivudine (Epzicom(®)/Kivexa(®)).

METHODS

Three Phase I, open, crossover studies with two (studies 1 and 3) or three (study 2) treatment periods were conducted in healthy individuals. In study 1, individuals received zidovudine and placebo or zidovudine and lersivirine on days 1-14. In study 2, individuals received lersivirine and tenofovir DF/emtricitabine, lersivirine and placebo or tenofovir DF/emtricitabine and placebo on days 1-10. In study 3, individuals received abacavir/lamivudine only in period 1 (5 days) and abacavir/lamivudine and lersivirine in period 2 (10 days). Blood samples were taken on days 1-14 (study 1) or day of final dose (studies 2 and 3) and analysed using high performance liquid chromatography/dual mass spectrometry. Pharmacokinetic parameters were calculated by standard non-compartmental methods.

RESULTS

When coadministered with lersivirine, zidovudine exposure increased by 35%, and exposure of its metabolite zidovudine-glucuronide decreased by 19%. Following coadministration of lersivirine and tenofovir DF/emtricitabine, tenofovir exposure increased by 30%, and lersivirine exposure decreased by 12%. Coadministration of lersivirine and abacavir/lamivudine increased abacavir exposure by 27% and decreased lamivudine exposure by 8%. Adverse events were predominantly mild in these Phase I studies.

CONCLUSIONS

Coadministration of lersivirine with zidovudine, tenofovir DF/emtricitabine or abacavir/lamivudine influenced the systemic exposure of all nucleoside reverse transcriptase inhibitor agents investigated (except for lamivudine; emtricitabine pharmacokinetics were not assessed). Changes were not considered clinically meaningful for zidovudine and abacavir. The clinical relevance of the effect on tenofovir pharmacokinetics is currently unknown.

Effects of ketoconazole and valproic acid on the pharmacokinetics of the next generation NNRTI, lersivirine (UK-453,061), in healthy adult subjects

AIMS

To investigate the effect of inhibitors of cytochrome P450 (CYP) 3A4 and glucuronidation (UGT2B7) on the pharmacokinetics of lersivirine (UK-453,061), a next generation non-nucleoside reverse transcriptase inhibitor with a unique resistance profile, and to investigate the safety and tolerability of co-administration of lersivirine with these inhibitors.

METHODS

Two open-label, randomized, placebo-controlled, crossover studies were conducted in healthy subjects. Study 1 investigated the effect of ketoconazole (400 mg once daily) on the pharmacokinetics of lersivirine (250 mg once daily). Subjects received ketoconazole 400 mg once daily or placebo on days 1-2 and received lersivirine 250 mg once daily and ketoconazole 400 mg once daily or placebo on days 3-9. Study 2 investigated the effect of valproic acid (VPA, sodium valproate, 1000 mg once daily) on the PK of lersivirine (500 mg once daily). On days 1-7, subjects received lersivirine 500 mg once daily plus either VPA 1000 mg or placebo.

RESULTS

Compared with lersivirine alone, co-administration with ketoconazole increased the lersivirine mean area under the curve (AUC(0,24 h)) and maximum plasma concentration (C(max) ) by 82% (90% CI 74%, 91%) and 61% (90% CI 41%, 83%), respectively. VPA increased the mean lersivirine AUC(0,24 h) by 25% (90% CI 16%, 35%), with little effect on C(max) (2.5%, 90% CI -9%, 16%). There were no serious adverse events and no treatment-related discontinuations from either study.

CONCLUSIONS

Inhibition of CYP3A4 and UGT2B7 by ketoconazole increased lersivirine exposure. Inhibition of UGT2B7-mediated glucuronidation by VPA had a modest effect on lersivirine exposure. Co-administration of lersivirine with either ketoconazole or VPA appeared to be well tolerated.

Long-term treatment with sildenafil citrate in pulmonary arterial hypertension: the SUPER-2 study

BACKGROUND

The long-term safety and tolerability of sildenafil treatment of pulmonary arterial hypertension (PAH) were assessed.

METHODS

Two hundred fifty-nine of 277 randomized and treated patients completed a 12-week, double-blind, placebo-controlled trial (SUPER-1 [Sildenafil Use in Pulmonary Arterial Hypertension]) of oral sildenafil in treatment-naive patients with PAH (96% functional class II/III) and entered an open-label uncontrolled extension study (SUPER-2) that continued until the last patient completed 3 years of sildenafil treatment. Patients titrated to sildenafil 80 mg tid; one dose reduction for tolerability was allowed during the titration phase.

RESULTS

The median duration of sildenafil treatment across SUPER-1 and SUPER-2 was 1,242 days (range, 1-1,523 days); 170 patients (61%) completed both studies, and 89 patients discontinued from SUPER-2. After 3 years, 87% of 183 patients on treatment were receiving sildenafil 80 mg tid. Of patients remaining under follow-up, 3%, 10%, and 18% were receiving a second approved PAH therapy at 1, 2, and 3 years, respectively. At 3 years post-SUPER-1 baseline, 127 patients had an increased 6-min walk distance (6MWD); 81 improved and 86 maintained functional class. Most adverse events were of mild or moderate severity. At 3 years, 53 patients had died (censored, n = 37). Three-year estimated survival rate was 79%; if all censored patients were assumed to have died, 3-year survival rate was 68%. No deaths were considered to be treatment related.

CONCLUSIONS

Long-term treatment of PAH initiated as sildenafil monotherapy was generally well tolerated. After 3 years, the majority of patients (60%) who entered the SUPER-1 trial improved or maintained their functional status, and 46% maintained or improved 6MWD.

Safety, tolerability and pharmacokinetics of an intravenous bolus of sildenafil in patients with pulmonary arterial hypertension

AIMS

To assess pharmacokinetics and pharmacodynamics of a 10 mg intravenous sildenafil bolus in pulmonary arterial hypertension (PAH) patients stabilized on 20 mg sildenafil orally three times daily.

METHODS

Pharmacokinetic parameters were calculated using noncompartmental analysis.

RESULTS

After an acute increase, plasma concentrations stabilized within the range reported previously for a 20 mg oral tablet. At 0.5 h, mean ± SD changes from baseline were -8.4 ± 11.7 mmHg (systolic pressure), -2.6 ± 7.3 mmHg (diastolic pressure) and -3.5 ± 10.4 beats min(-1) (heart rate). There was no symptomatic hypotension.

CONCLUSIONS

Although further research is warranted, a 10 mg sildenafil intravenous bolus appears to provide similar exposure, tolerability and safety to the 20 mg tablet.

A randomized, controlled, multicentre trial comparing pegvisomant alone with combination therapy of pegvisomant and long-acting octreotide in patients with acromegaly

OBJECTIVE

For patients with acromegaly who are suboptimally controlled on long-acting octreotide (LAR), treatment options are to switch to pegvisomant monotherapy (PM) or add pegvisomant to LAR (P-LAR). Our objective was to evaluate if the safety and efficacy of these regimens differ.

DESIGN

This was an open-label, multicentre, randomized, 40-week outpatient study. The control arm consisted of patients controlled on LAR (n = 28).

PATIENTS

A total of 27 patients with suboptimally controlled acromegaly [as indicated by a serum IGF-I level > or = 1.3 x upper limit of normal (ULN) of the age-related reference range] were randomized to PM (10 mg once daily initially, then adjusted in 5-mg increments every 8 weeks based on IGF-I levels) and 29 to P-LAR (LAR dosing remained fixed).

MEASUREMENTS

The primary end-point was adverse events (AEs). The secondary end-point was biochemical IGF-I-based efficacy. The RIA for IGF-I was discontinued by the manufacturer during the study and a chemiluminescent assay was subsequently used. Previously obtained IGF-I levels were re-analysed.

RESULTS

PM and P-LAR were well tolerated and there were no differences in the number of AEs. Patients receiving P-LAR tended to be more likely to have clinically significant increases in hepatic transaminase levels, especially those receiving high-dose LAR. Normalization of IGF-I was similar with both regimens (56% and 62% of patients for PM and P-LAR respectively). The change in IGF-I assay resulted in lower rates of IGF-I normalization than expected. Reductions in fasting glucose levels were greater with PM than with P-LAR (-0.8 mmol/l; 95% confidence interval -1.16, -0.53 mmol/l).

CONCLUSIONS

In patients suboptimally controlled on LAR, PM and P-LAR were equally well tolerated and effective in normalizing IGF-I, and overall clinical improvement was observed with both regimens. Thus, pegvisomant monotherapy and adjunctive therapy are equally viable options for the treatment of LAR-resistant acromegaly.

Effect of single doses of maraviroc on the QT/QTc interval in healthy subjects

AIMS

To assess the effect of a single dose of maraviroc on the QTc interval in healthy subjects and to evaluate the QTc interval-concentration relationship.

METHODS

A single-dose, placebo- and active-controlled, five-way crossover study was conducted to investigate the effects of maraviroc (100, 300, 900 mg) on QTc in healthy subjects. Moxifloxacin (400 mg) was used as the active comparator. The study was double-blind with respect to maraviroc/placebo and open label for moxifloxacin. There was a 7-day wash-out period between each dose. QT interval measurements obtained directly from the electrocardiogram (ECG) recorder were corrected for heart rate using Fridericia's correction (QTcF). A placebo run-in day was conducted before period 3, when ECGs were collected at intervals while subjects were resting or during exercise. These ECGs plus other predose ECGs were used to evaluate the QT/RR relationship for each subject to enable calculation of an individual's heart rate correction for their QT measurements (QTcI). ECGs were taken at various intervals pre- and postdose in each study period. Pharmacokinetic parameters were determined for each maraviroc dose. The end-points that were evaluated were QTcF at median time to maximum concentration (T(max)) based on the machine readings and QTcI at median T(max) based on manual over-reads of the QT/RR data. A separate analysis of variance was used for each of the pair-wise comparisons for each end-point. The relationship between QTc interval and plasma concentration was also investigated using a mixed-effects modelling approach, as implemented by the NONMEM software system. A one-stage model was employed in which the relationship between QT and RR and the effects of maraviroc plasma concentration on QT were estimated simultaneously.

RESULTS

The mean difference from placebo in machine-read QTcF at median T(max) for maraviroc 900 mg was 3.6 ms [90% confidence interval (CI) 1.5, 5.8]. For the active comparator, moxifloxacin, the mean difference from placebo in machine-read QTcF was 13.7 ms. The changes from placebo for each of the end-points were similar for men and women. No subjects receiving maraviroc or placebo had a QTcF > or = 450 ms (men) or QTcF > or = 470 ms (women), nor did any subject experience a QTcF increase > or = 60 ms from baseline at any time point. Analysis based on the QTcI data obtained from the manual over-readings of the ECGs gave numerically very similar results. The QT:RR relationship was similar pre- and postdose and was not related to maraviroc concentration. The population estimate of the QT:RR correction factor was 0.324 (95% CI 0.309, 0.338). The population estimate of the slope describing the QT-concentration relationship was 0.97 micros ml ng(-1) (95% CI -0.571, 2.48), equivalent to an increase of 0.97 ms in QT per 1000 ng maraviroc plasma concentration. Most adverse events were mild to moderate in severity.

CONCLUSIONS

Single doses of maraviroc, up to and including 900 mg, had no clinically relevant effect on QTcF or QTcI. At all maraviroc doses and for both end-points, the mean difference from placebo for QTc was < 4 ms. There was no apparent relationship between QT interval and maraviroc plasma concentration up to 2363 ng ml(-1). This conclusion held in both male and female subjects, and there was no evidence of a change in the QT/RR relationship with concentration.

Efficacy and tolerability of sumanirole in restless legs syndrome: a phase II, randomized, double-blind, placebo-controlled, dose-response study

OBJECTIVE

To compare the efficacy, safety and tolerability of sumanirole with placebo in patients with idiopathic restless legs syndrome (RLS).

METHODS

In this double-blind, placebo-controlled, randomized, parallel-group, dose-response study, 270 patients with idiopathic RLS were enrolled and randomized to receive sumanirole 0.5, 1.0, 2.0, or 4.0mg, or placebo. The primary efficacy endpoint was mean change of the total score of the International Restless Legs Scale (IRLS-10), a 10-item scale, from baseline to end of maintenance. Secondary assessments included polysomnography (PSG) variables.

RESULTS

Treatment with sumanirole was well tolerated. Mean change in IRLS-10 showed no statistically significant change compared with placebo at any dose, although the mean change with the 4.0-mg dose was numerically greater than the other doses and placebo. PSG variables, specifically the periodic leg movements during sleep, showed statistically significant dose-related improvement in favor of sumanirole. Consistent with earlier multinational, multicenter studies in RLS, high placebo response rates were seen with IRLS-10 but not with PSG variables.

CONCLUSIONS

Given data published in Parkinson's disease, the dose range of sumanirole selected here may have been too low. Alternatively, dopamine D(2) selective agents could be intrinsically less effective than agonists with combined D(2)/D(3) activity. Sumanirole demonstrated an excellent safety profile.

A comparison of sumanirole versus placebo or ropinirole for the treatment of patients with early Parkinson's disease

To assess the safety and efficacy of sumanirole, a highly selective dopamine agonist, versus placebo and demonstrate its noninferiority to ropinirole, 614 patients with early Parkinson's disease (PD) were treated with sumanirole, 1 to 16 mg/day; ropinirole, 0.75 to 24 mg/day; or placebo. Primary end point in this flexible-dose, double-blind, double-dummy, parallel-group study of 40 weeks was the change in total sum of the United Parkinson's Disease Rating Scale (UPDRS) Parts II + III scores from baseline to end of maintenance. Approximately half the subjects in the sumanirole and placebo groups withdrew early from the study, most (51.8% and 68.5%, respectively) due to lack of efficacy. Of the ropinirole subjects who withdrew (50.5%), most discontinued because of adverse events. In sumanirole and ropinirole groups, mean changes from baseline of -2.48 and -5.20 in UPDRS II + III mean scores were significant versus 0.38 in the placebo group (P </= 0.006). Sumanirole and ropinirole are effective in the treatment of patients with early PD when compared with placebo. Noninferiority of sumanirole to ropinirole was not demonstrated, with a difference of 2.70 (90% CI, 0.92-4.49). Sumanirole was better tolerated than ropinirole.

Man versus machine: is there an optimal method for QT measurements in thorough QT studies?

Electrocardiographic (ECG) recordings from 3 placebo-controlled thorough QT healthy volunteer studies were used to compare QT intervals obtained by manual measurement with those generated by ECG machines. The effect of the positive control was compared to placebo at each time point for data obtained from both sources. Both manual and automated techniques consistently demonstrated statistically significant prolongation of QTcF with the positive controls. The proportion of outlier values was small for both methods. The pairwise comparison between manual and automated uncorrected QT intervals demonstrated clear differences, with intervals derived from one machine on average 16 to 19 milliseconds shorter and from the other 7 milliseconds longer than the manually measured QT intervals, but these differences disappeared when analyzing QT change from baseline. Both manual and automated, commercially available QT algorithms demonstrated small statistically significant effects on the QTc interval induced by positive controls.

Pharmacokinetics of fosfluconazole and fluconazole following multiple intravenous administration of fosfluconazole in healthy male volunteers

AIMS

To assess the bioavailability of fluconazole (FLCZ) from phosphate pro-drug (fosfluconazole), to investigate the effect of loading doses on the time to achieve FLCZ steady state plasma concentrations and on safety, and to investigate the pharmacokinetics of fosfluconazole following once daily multiple bolus injection of fosfluconazole in healthy male volunteers.

METHODS

The first study was a randomized, double-blind, double dummy, two-period crossover study. Subject received either 1000 mg fosfluconazole or 800 mg FLCZ once daily for 14 days in random order. The second study was an open label, randomized parallel group study. Subjects received one of three fosfluconazole once daily treatments: 500 mg for 10 days (no loading dose), a loading dose of 1000 mg on day 1 followed by 500 mg for 9 days (one loading dose), or loading doses of 1000 mg on days 1 and 2 followed by 500 mg for 8 days (two loading doses).

RESULTS

The estimated mean (90% CI) bioavailability of FLCZ from fosfluconazole was 96.8% (94.5, 99.2), with a C(max,ss) ratio of 98.3% (93.3, 103.5) in the first study. Less than 1% of the administered dose of fosfluconazole was excreted unchanged in the urine and the majority (85.6%) was eliminated in the urine as FLCZ. In the second study two loading doses regimen led to earlier achievement of target steady state plasma concentrations (by day 3) compared with use of one or no loading dose (towards the end of the dosing period). Similar adverse event profiles were seen in all three treatment groups. Fosfluconazole did not accumulate after multiple dosing.

CONCLUSIONS

Multiple administration of 1000 mg fosfluconazole and 800 mg FLCZ produced equivalent systemic exposure to FLCZ. Steady state FLCZ plasma concentrations were achieved earliest when two loading doses were used.

The effects of renal impairment on the pharmacokinetics and safety of fosfluconazole and fluconazole following a single intravenous bolus injection of fosfluconazole

AIMS

Fosfluconazole is a phosphate prodrug of fluconazole (FLCZ). This study was conducted to investigate the effect of renal impairment on the pharmacokinetics of fosfluconazole and FLCZ, and to assess the safety and toleration of fosfluconazole following a single intravenous bolus injection of fosfluconazole in subjects with normal and impaired renal function.

METHODS

In an open, parallel-group, two-centre study, subjects with normal and impaired renal function received a single 1000-mg bolus intravenous injection of fosfluconazole. Subjects were categorized as Normal (> 80 ml min(-1)), Mild (51-80 ml min(-1)), Moderate (30-50 ml min(-1)) or Severe (< 30 ml min(-1)) impairment group according to their Cockcroft and Gault creatinine clearance (CLcr) values. Concentrations of fosfluconazole and FLCZ were determined in plasma and urine samples taken up to 240 h and 48 h postdose, respectively.

RESULTS

Fosfluconazole plasma concentrations were very similar across the four groups, and there was no apparent relationship between any of the fosfluconazole pharmacokinetic parameters with increasing renal impairment. The conversion of fosfluconazole to FLCZ was unaffected by the degree of renal impairment. Only small amounts of fosfluconazole were excreted in the urine suggesting almost complete conversion to FLCZ. FLCZ concentrations were still detected in plasma after 240 h postdose and remained higher at the later sampling times in subjects in the Moderate and Severe groups. The area under the plasma concentration vs. time curve between time zero and infinity (AUC), the terminal elimination phase half-life (t(1/2)) and the mean residence time (MRT) of FLCZ all increased with the degree of renal impairment. The ratios (95% confidence interval) for AUC (Renal impairment group/Normal group) were 112.8% (89.5, 142.1), 240.6% (128.2, 451.4) and 355.1% (259.3, 486.3) for the Mild, Moderate and Severe impairment groups, respectively. There was a linear relationship between CLcr with AUC, t(1/2), MRT and the total plasma clearance of FLCZ (CL/F). Both the amount excreted over 48 h in the urine and the renal clearance of FLCZ decreased with an increase in renal impairment. The adverse events reported were mild to moderate in intensity, and there was no observed relationship with impairment group. There were no severe or serious adverse events, and in general fosfluconazole was well tolerated.

CONCLUSIONS

The pharmacokinetics of fosfluconazole, including its efficient conversion into FLCZ, were unaffected by renal impairment. For FLCZ, there was a significant linear relationship between CLcr and AUC, t(1/2), MRT and CL/F, with AUC, t(1/2) and MRT increasing and CL/F decreasing as renal impairment increased. The dose adjustment used for FLCZ (half normal dose for patients with CLcr at <or= 50 ml min(-1)) can be applied to fosfluconazole as well. There were no safety concerns for any subject in this study, and fosfluconazole and FLCZ were well tolerated by all the treatment groups.

Comparison of the pharmacokinetics of fosfluconazole and fluconazole after single intravenous administration of fosfluconazole in healthy Japanese and Caucasian volunteers

OBJECTIVES

To investigate the bioavailability of fluconazole (FLCZ) from fosfluconazole (phosphate pro-drug of FLCZ) and to compare the pharmacokinetics of fosfluconazole and FLCZ in Japanese and Caucasian subjects.

METHODS

In a randomised, double-blind, double-dummy, single-dose, two-period, crossover study, 12 Japanese and 12 Caucasian healthy subjects received a bolus intravenous injection of 1000 mg fosfluconazole or an intravenous infusion of 800 mg FLCZ in random order. Concentrations of fosfluconazole and FLCZ were determined in plasma and urine samples taken up to 144 h and 48 h post-dose, respectively.

RESULTS

The bioavailability of FLCZ after administration of fosfluconazole was 95.2% (95% confidence interval: 89.0, 102.0) in Japanese subjects and 100.6% (94.0, 107.7) in Caucasian subjects. The ratio of bioavailabilities (Japanese/Caucasian) was 94.7% (86.0, 104.3). There were no statistically significant differences in the pharmacokinetic parameters of fosfluconazole (except for AUC(inf)) and FLCZ between Japanese and Caucasian subjects. Although mean AUC(inf) of fosfluconazole was 25.6% (5.6, 49.2) greater in Japanese subjects, the lack of a statistically significant difference in weight-adjusted CL of fosfluconazole demonstrates that the difference in AUC(inf) was due to a difference in body weight. The adverse-event profile was similar in Japanese and Caucasian subjects after both fosfluconazole and FLCZ dosing, and both treatments were well tolerated in each group.

CONCLUSIONS

The pharmacokinetics of fosfluconazole and FLCZ were similar in Japanese and Caucasian subjects. Fosfluconazole is almost completely converted to FLCZ and similar systemic exposure to FLCZ is achieved after single doses of fosfluconazole in both Japanese and Caucasian subjects.

Effect of omeprazole on the steady-state pharmacokinetics of voriconazole

AIMS

Voriconazole, a novel triazole antifungal agent, is metabolized by the cytochrome P450 isoenzymes CYP2C19, CYP2C9, and to a lesser extent by CYP3A4. Omeprazole, a proton pump inhibitor used widely for the treatment of gastric and duodenal ulcers, is predominantly metabolized by CYP2C19 and CYP3A4. The aim of this study was to determine the effects of omeprazole on the steady-state pharmacokinetics of voriconazole. A secondary objective was to characterize the pharmacokinetic profile of an oral loading dose regimen of 400 mg twice-daily voriconazole on day 1.

METHODS

This was an open, randomized, placebo-controlled, two-way crossover study of 18 healthy male volunteers. Subjects received oral voriconazole (400 mg twice daily on day 1 followed by 200 mg twice daily on days 2-9 and a single 200-mg dose on day 10) with either omeprazole (40 mg once daily) or matched placebo for 10 days. There was a minimum 7-day washout between treatment periods.

RESULTS

Mean Cmax and AUCtau of voriconazole were increased by 15%[90% confidence interval (CI) 5, 25] and 41% (90% CI 29, 55), respectively, with no effect on tmax during coadministration of omeprazole. Visual inspection of predose plasma concentrations (Cmin) indicated that steady-state plasma concentrations were achieved following the second loading dose. One subject withdrew from the study during the voriconazole + omeprazole treatment period because of treatment-related abnormal liver function test values. All other treatment-related adverse events resolved without intervention.

CONCLUSIONS

Omeprazole had no clinically relevant effect on voriconazole exposure, suggesting that no voriconazole dosage adjustment is necessary for patients in whom omeprazole therapy is initiated. Administration of a 400-mg twice-daily oral loading dose regimen on day 1 resulted in steady-state plasma levels of voriconazole being achieved following the second loading dose.

No clinically significant effect of erythromycin or azithromycin on the pharmacokinetics of voriconazole in healthy male volunteers

AIMS

The antibiotic erythromycin is a potent inhibitor of cytochrome P450 CYP3A4 metabolism. As CYP isozymes, including CYP3A4, are involved in the metabolism of the new triazole voriconazole, this study investigated the effects of multiple-dose erythromycin or azithromycin on the steady-state pharmacokinetics of voriconazole in healthy male subjects.

METHODS

In an open, randomized, parallel-group, single-centre study, 30 healthy male subjects aged 20-41 years received oral voriconazole 200 mg twice daily for 14 days plus either erythromycin (1 g twice daily on days 8-14), azithromycin (500 mg once daily on days 12-14) or placebo (twice daily on days 8-14). Only morning doses were administered on day 14. Plasma concentrations of voriconazole were measured up to 12 h postdose on days 7 and 14, and plasma pharmacokinetic parameters were calculated. Adverse events and standard laboratory test results were recorded before and throughout the study.

RESULTS

Comparison of the voriconazole Cmax day 14/day 7 ratio for the voriconazole + erythromycin group with that of the voriconazole + placebo group yielded a ratio of 107.7%[90% confidence interval (CI) 90.6, 128.0]; for the voriconazole + azithromycin group, the ratio was 117.5% (90% CI 98.8, 139.7). Comparison of the voriconazole AUCtau day 14/day 7 ratios of the voriconazole + erythromycin and voriconazole + azithromycin groups with that of the voriconazole + placebo group showed ratios of 101.2% (90% CI 89.1, 114.8) and 107.9% (90% CI 95.1, 122.4), respectively. For voriconazole tmax, the differences between the day 14-day 7 calculations for the voriconazole + erythromycin or the voriconazole + azithromycin groups and that of the voriconazole + placebo group were - 0.2 h (90% CI - 0.8, 0.3) and - 0.1 h (90% CI - 0.7, 0.5), respectively. None of these changes was considered clinically relevant. The study drugs were well tolerated by subjects in all groups; the most common study drug-related adverse events were visual disturbances, reported in all groups, and abdominal pain, present in the voriconazole + erythromycin group.

CONCLUSIONS

Coadministration of erythromycin or azithromycin does not affect the steady-state pharmacokinetics of voriconazole in a clinically relevant manner in healthy male subjects.

Immunization with a DNA expression vector encoding the varicella zoster virus glycoprotein E (gE) gene via intramuscular and subcutaneous routes

In this study we constructed a plasmid containing the gene encoding varicella-zoster virus transmembrane glycoprotein gE (VZV gE) and evaluated its utility for DNA immunization in mice. Our initial work demonstrates that intramuscular and subcutaneous injection of VZV gE DNA, without the use of costimulatory molecules or other adjuvant materials, results in the generation of antigen-specific antibodies of primarily the IgG2a subclass, indicating that this vaccine can stimulate Th1 type immunity. This is the first report of a prototype DNA vaccine for varicella-zoster virus.

Intratype sequence variation among clinical isolates of the human papillomavirus type 6 L1 ORF: clustering of mutations and identification of a frequent amino acid sequence variant

Human papillomavirus type 6 (HPV-6) is the causative agent of condyloma acuminata, a common sexually transmitted disease. Virus-like particles (VLPs) assembled from the L1 major capsid protein represent promising candidates for prophylactic vaccines. However, any intratype sequence variation among HPV-6 L1 ORFs will influence which sequence is used for a vaccine according to its prevalence in the population and its propensity for VLP production. Therefore, we have analysed the entire L1 nucleotide sequence of 17 clinical isolates of HPV-6 from the London area. We found 28 positions where changes from the prototype HPV-6b L1 occurred, showing that HPV-6 L1 intratype variation is greater than previously reported. The most frequently observed substitutions are clustered into three discrete regions: R1 (nt 5920-6075), R2 (nt 6590-6670) and R3 (nt 7070-7230). Indeed, most of the nucleotide substitutions within the HPV-6 L1 reported worldwide also map to these regions. The R3 region contains predominantly non-silent substitutions, the most common of which is a G-to-C substitution at position 7079. This results in a Glu-to-Gln change at aa 431, although this change had no effect on VLP yield or stability. This substitution defines a new HPV-6 L1 amino acid sequence that is more abundant in the isolates examined than any other reported sequence.

Protection from Plasmodium berghei infection by priming and boosting T cells to a single class I-restricted epitope with recombinant carriers suitable for human use

The desirability of inducing cytotoxic T cell responses to defined epitopes in humans has led to the development of a variety of recombinant delivery systems. Recombinant protein particles derived from a yeast retrotransposon (Ty) and the modified Ankara vaccinia (MVA) virus can deliver large epitope strings or even whole proteins. Both have previously been administered safely in humans. Immunization with recombinant Ty and MVA containing a single Plasmodium berghei class I-binding epitope provided 95% sterile protection against malaria in mice. The sequence of immunization, Ty followed by MVA, was critical to elicit high levels of IFN-gamma-producing cells and protection. The reciprocal sequence (MVA/TY) or homologous boosting was not protective. Both constructs (Ty and MVA) contain the H-2Kd-restricted pb9 CTL epitope from the circumsporozoite protein of P. berghei among a string of 8-15 human P. falciparum-derived CTL epitopes restricted through 7 common HLA alleles as well as widely recognized CD4 T cell epitopes. Thus, the novel recombinant Ty/MVA prime/boost combination with these constructs provides a safe alternative for evaluation for human vaccination against P. falciparum malaria.

Effect of food and gender on the pharmacokinetics of tucaresol in healthy volunteers

AIMS

The potential effects of food and gender on the pharmacokinetics of tucaresol were investigated in healthy volunteers.

METHODS

Ten males (mean weight 76.5 kg, age 27-42 years) and eight females (mean weight 58.9 kg, age 18-44 years) received a single oral dose of 200 mg tucaresol on two occasions in random order. On one occasion, tucaresol was given after an overnight fast and on the other, immediately after ingestion of a standard breakfast.

RESULTS

There were no significant differences in standard pharmacokinetic parameters between the two occasions but the rate of tucaresol absorption was faster after food intake. Female subjects had higher Cmax (ratio 1.25 with 95% CI 1.10-1.44) and AUC (ratio 1.25 with 95% CI 1.05-1.49) values than males but the differences were due to the higher body weights of the males; weight-adjusted apparent total clearance values (CL/F) were not different between genders (ratio 1.03 with 95% CI 0.87-1.21).

CONCLUSIONS

Food intake and gender have no significant effect on the exposure to orally administered tucaresol.

The novel anti-migraine compound zolmitriptan (Zomig 311C90) has no clinically significant interactions with paracetamol or metoclopramide

OBJECTIVE

This study investigated potential pharmacokinetic or pharmacodynamic interactions between the novel anti-migraine compound zolmitriptan (Zomig, formerly 311C90) and paracetamol and/or metoclopramide.

METHODS

In an open-label, randomised, crossover study, 15 healthy volunteers received single oral doses of 10 mg zolmitriptan alone, 1 g paracetamol alone, 10 mg zolmitriptan + 1 g paracetamol, 10 mg zolmitriptan + 10 mg metoclopramide or 10 mg zolmitriptan + 1 g paracetamol + 10 mg metoclopramide on five separate occasions.

RESULTS

Metoclopramide had no significant effects on the pharmacokinetics of zolmitriptan or the active zolmitriptan metabolite 183C91, nor did it affect interactions between zolmitriptan and paracetamol. Paracetamol marginally increased the maximum plasma concentration (Cmax) (11%) and the area under the curve (AUC) (11%) and reduced the renal clearance of zolmitriptan (9%); similar small effects were seen on 183C91. The AUC, Cmax and half-life of paracetamol were reduced by concomitant zolmitriptan (by 11%, 31% and 8%, respectively), whilst the mean residence time showed a small increase (+0.7 h). There was a trend towards a transient increase in blood pressure following all regimens containing zolmitriptan; this effect was small, was consistent between all zolmitriptan regimens as well as with previous studies, and was considered to be clinically insignificant. Zolmitriptan was well tolerated after all treatment regimens.

CONCLUSION

Concomitant administration of zolmitriptan and paracetamol resulted in a slight increase in bioavailability of zolmitriptan and a reduced rate and extent of paracetamol absorption. These findings are considered to be of no clinical significance and there is no reason to avoid concomitant administration of paracetamol and/or metoclopramide with zolmitriptan.

Lack of interaction between valaciclovir, the L-valyl ester of aciclovir, and digoxin

AIMS

Changes in both digoxin and aciclovir renal clearance following coadministration with some other renally eliminated drugs have been reported. The potential interaction of valaciclovir, with its antiherpetic metabolite aciclovir, and digoxin was investigated.

METHODS

Twelve healthy volunteers (seven males, five females) participated in an open, randomized, four-period crossover study. Valaciclovir, 1000 mg, was given alone on one occasion, and on another, after the second of two 0.75 mg digoxin doses administered 12 h apart. Blood samples and all urine were collected up to 12 h following the valaciclovir dose for aciclovir radioimmunoassay. On a third occasion, digoxin was given alone and on a fourth, with 1000 mg valaciclovir three times/day for 8 days starting 12 h before the first digoxin dose. Blood samples were taken up to 168 h and all urine collected up to 24 h following the second dose for digoxin radioimmunoassay.

RESULTS

There were no clinically significant differences in digoxin or aciclovir pharmacokinetic parameters when digoxin or valaciclovir was given alone or in combination.

CONCLUSIONS

No dosage adjustment is required when valaciclovir and digoxin are coadministered.

The interaction between propranolol and the novel antimigraine agent zolmitriptan (311C90)

AIMS

Zolmitriptan (Zomig, formerly known as 311C90), a selective 5HT1B/1D agonist is under development as an acute oral treatment for migraine. Despite the use of prophylactic medication, such as propranolol, breakthrough attacks often occur in patients. Consequently we investigated the effects of propranolol on the pharmacokinetics of, and cardiovascular responses to, zolmitriptan.

METHODS

A double-blind, randomized, crossover study of the effects of pre-treatment with propranolol 160 mg daily for 7 days or placebo on the pharmacokinetics and effects on blood pressure of a single 10 mg dose of zolmitriptan in 12 healthy volunteers.

RESULTS

Propranolol increased mean zolmitriptan Cmax and AUC by 56% and 37% respectively; mean t1/2 was prolonged from 3.1 to 4.0 h. Mean Cmax and AUC of the pharmacologically active N-desmethyl metabolite were reduced by 24% and 11% respectively and the metabolite:parent AUC ratio (AUCm/AUCp) fell from 0.46 to 0.26. Mean Cmax and AUC for the inactive indole acetic acid metabolite were both reduced by 13% and AUCm/AUCp from 1.04 to 0.59. A small pressor effect of short duration was observed following zolmitriptan with mean peak rises of 13 and 11 mmHg in systolic and diastolic pressures respectively; propranolol had no effect on the pressor response.

CONCLUSIONS

The results suggest that propranolol inhibits biotransformation of zolmitriptan but with no change in the small pressor response to zolmitriptan. It is therefore unlikely that the pharmacokinetic changes will lead to clinically important changes in pharmacological effects and dosage adjustment of zolmitriptan is not required in patients taking propranolol for migraine prophylaxis.

Mucosal or targeted lymph node immunization of macaques with a particulate SIVp27 protein elicits virus-specific CTL in the genito-rectal mucosa and draining lymph nodes

The major routes of HIV transmission are through the rectal and cervico-vaginal mucosa. To prevent dissemination of HIV to the regional lymph nodes (LNs), an effective vaccine may need to stimulate CTL in the rectal or genital tract and the draining LNs. We report that mucosal immunization by the recto-oral and vagino-oral route or s.c. immunization targeting the iliac LNs with a particulate SIVp27:Ty-VLP vaccine elicits SIVgag-specific CTL in the regional LNs as well as in the spleen and PBMC. Targeted LN immunization with this vaccine elicited MHC class I-restricted CD8+ CTL responses, and the highest frequency of CTL was found in the iliac LNs. Moreover, SIVgag-specific CTL activity was detected in short term T cell lines established in mononuclear cells eluted from the rectal and cervico-vaginal mucosa. The relative frequency of CTL in short term cell lines prepared from the rectal mucosa (21/113 or 18.6%) was similar to that obtained from the cervico-vaginal mucosa (16/79 or 20.3%). Examination of the relative frequency of CTL to the T cell epitopes residing within SIVp27 showed a higher frequency in iliac LN cells to peptide aa 41-70 than in that to peptide aa 121-150, and this was significant after both recto-oral (chi-squared 6.500, p < 0.02) and vagino-oral (chi-squared = 10.391, p < 0.01) immunization. In contrast, the relative frequency of CTL in PBMC to peptide aa 41-70 (15.5%) was comparable to that elicited by peptide aa 121-150 (17.6%). This study provides novel evidence that mucosal or targeted LN immunization can generate anti-SIV CTL in the rectal and genital mucosa, in the draining LNs, and in the central lymphoid system.

Mucosal or targeted lymph node immunization of macaques with a particulate SIVp27 protein elicits virus-specific CTL in the genito-rectal mucosa and draining lymph nodes

The major routes of HIV transmission are through the rectal and cervico-vaginal mucosa. To prevent dissemination of HIV to the regional lymph nodes (LNs), an effective vaccine may need to stimulate CTL in the rectal or genital tract and the draining LNs. We report that mucosal immunization by the recto-oral and vagino-oral route or s.c. immunization targeting the iliac LNs with a particulate SIVp27:Ty-VLP vaccine elicits SIVgag-specific CTL in the regional LNs as well as in the spleen and PBMC. Targeted LN immunization with this vaccine elicited MHC class I-restricted CD8+ CTL responses, and the highest frequency of CTL was found in the iliac LNs. Moreover, SIVgag-specific CTL activity was detected in short term T cell lines established in mononuclear cells eluted from the rectal and cervico-vaginal mucosa. The relative frequency of CTL in short term cell lines prepared from the rectal mucosa (21/113 or 18.6%) was similar to that obtained from the cervico-vaginal mucosa (16/79 or 20.3%). Examination of the relative frequency of CTL to the T cell epitopes residing within SIVp27 showed a higher frequency in iliac LN cells to peptide aa 41-70 than in that to peptide aa 121-150, and this was significant after both recto-oral (chi-squared 6.500, p &lt; 0.02) and vagino-oral (chi-squared = 10.391, p &lt; 0.01) immunization. In contrast, the relative frequency of CTL in PBMC to peptide aa 41-70 (15.5%) was comparable to that elicited by peptide aa 121-150 (17.6%). This study provides novel evidence that mucosal or targeted LN immunization can generate anti-SIV CTL in the rectal and genital mucosa, in the draining LNs, and in the central lymphoid system.

Comparison of numerous delivery systems for the induction of cytotoxic T lymphocytes by immunization

A variety of vaccine delivery systems including peptides with various adjuvants, recombinant particles, live recombinant viruses and bacteria and plasmid DNA were tested for their ability to induce CD8+ cytotoxic T lymphocytes (CTL) against a well-defined epitope (amino acids 252-260) from the circumsporozoite (CS) protein of Plasmodium berghei. We compared routes of immunization that would be applicable for the administration of a malaria vaccine in humans. The majority of these vaccines did not induce high CTL responses in the spleens of immunized mice. However, both a yeast-derived Ty virus-like particle expressing the optimal nine-amino acid epitope SYIPSAEKI from the CS protein (CSP-VLP) and a lipid-tailed peptide of this same sequence induced high levels of the major histocompatibility complex (MHC) class I-restricted CTL with one and three subcutaneous immunizations, respectively. Moreover, these CTL were able to recognize naturally processed antigen expressed by a recombinant vaccinia virus. The levels of CTL induced by CSP-VLP could be augmented by co-immunization with certain cytokines. Target cells pulsed with CSP-VLP were recognized and lysed, showing that the particles were effectively processed and presented through MHC class I presentation pathway. The levels of CTL induced using CSP-VLP and lipopeptides are comparable to those observed after immunization with multiple doses of irradiated sporozoites.

Generation of diversity in the hierarchy of T-cell epitope responses following different routes of immunization with simian immunodeficiency virus protein

OBJECTIVES

To examine whether the route of immunization determines the hierarchy of T-cell epitope proliferative responses in macaques.

DESIGN

Macaques were immunized with a recombinant simian immunodeficiency virus (SIV) p27 core protein by the intramuscular, male and female genital or rectal route, each of which was augmented by oral immunization, and by the novel targeted lymph-node immunization route. Overlapping peptides were used to identify the proliferative T-cell epitopes and to determine their hierarchy in the circulation, spleen and lymph nodes.

METHODS

T-cell epitope mapping of the proliferative responses was studied in short-term cell lines. Dendritic cells and macrophages were enriched by metrizamide gradient and adherence to plastic, respectively.

RESULTS

Intramuscular immunization elicited in the circulating T cells a hierarchy of T-cell epitopes within four peptides in the following descending order of frequency: peptides 121-140 (57.9%), 41-60 (28.9%), 61-80 (18.9%) and 101-120 (5.4%). The hierarchy of these four T-cell epitope responses differed significantly with each of the five routes of immunization, when circulating (P < 0.001), splenic (P < 0.02-< 0.001) or iliac lymph-node cells (P < 0.001) were analysed. The effect of antigen-presenting cells was then investigated and enriched dendritic cells were more effective than macrophages in processing and presenting the p27 antigen and the immunodominant (121-140) and 61-80 T-cell epitopes.

CONCLUSIONS

The route of immunization may determine the hierarchy of T-cell epitopes in the lymph nodes draining the mucosa in the circulating and splenic lymphocytes. The diversity of T-cell epitopes may affect the control of HIV at different anatomical sites, the administration route of the vaccine, and selection of polypeptides or recombinant antigens for immunization.