Replication and Excretion of the Live Attenuated Tetravalent Dengue Vaccine CYD-TDV in a Flavivirus-Naive Adult Population: Assessment of Vaccine Viremia and Virus Shedding.

Background: We assessed replication and excretion of the live attenuated tetravalent dengue vaccine (CYD-TDV) into biological fluids following vaccination in dengue-naive adults in Australia. Methods: Vaccinal viremia/shedding was assessed in a subset of participants enrolled in a lot-to-lot consistency study; 95 participants received 3 subcutaneous doses of CYD-TDV from phase 2/3 lots of the vaccine, and 8 received placebo; doses were administered 6 months apart. Quantitative reverse-transcription polymerase chain reaction (qR-PCR) analysis was used to initially detect the yellow fever virus (YFV) core protein gene in the backbone of CYD-TDV in serum, saliva and urine, followed by serotype-specific qRT-PCR analysis of samples positive for YFV by qRT-PCR (lower limit of detection, 5.16 GEq/mL). Results: YFV viremia was detected by qRT-PCR in 69.5% of participants (66 of 95) who received CYD-TDV, mainly 6-14 days after injection 1. The serotypes detected were serotype 4 (in 68.2% of participants [45 of 95]), serotype 3 (in 19.7% [13 of 95]), and serotype 1 (in 12.1% [8 of 95]); serotype 2 was not detected. None of the placebo recipients had vaccinal viremia/shedding. No participants had detectable viral shedding into saliva at levels above the lower limit of quantitation. Two participants had low-level viral shedding (serotype 3) in urine (5.47 and 5.77 GEq/mL). None of the participants with viremia or shedding experienced concomitant fever. Conclusions: Low-level vaccinal viremia may occur following vaccination with CYD-TDV, but this is not associated with any symptom or adverse event. Clinical Trials Registration: NCT01134263.

Tildrakizumab, a novel anti-IL-23 monoclonal antibody, is unaffected by ethnic variability in Caucasian, Chinese, and Japanese subjects.

OBJECTIVE: To evaluate the effect of ethnicity on the pharmacokinetics (PK) of tildrakizumab, a novel anti-IL-23 monoclonal antibody for the treatment of psoriasis. MATERIALS AND METHODS: This was an open-label, 2-part study in healthy adult subjects. In part 1, Japanese subjects and matched Caucasian and Chinese subjects (to Japanese) were assigned to 1 of 3 cohorts and administered tildrakizumab 50, 200, or 400 mg subcutaneously (SC). In part 2, Japanese subjects received tildrakizumab 10 mg/kg IV. Pre- and post-treatment antidrug antibodies were assessed. Safety and tolerability were assessed throughout the study. RESULTS: 59 subjects were enrolled; 53 in part 1 and 6 in part 2. Overall geometric mean AUC∞ was 6.15, 6.05, and 6.32 day×µg/mL/mg in Japanese, Caucasian, and Chinese subjects, respectively, after administration of a single SC dose. Bioavailability was ~92%. Six out of 58 evaluable subjects were positive for post-treatment ADA; 2 of these positive subjects had reduced tildrakizumab exposure. Most AEs were mild in intensity and the most frequent treatment-related AEs were injection site hematoma (15%), injection site pain (10%), and injection site erythema (8%). CONCLUSIONS: The pharmacokinetics of tildrakizumab were similar in Japanese, Caucasian, and Chinese subjects. Tildrakizumab exposure increased proportionally with dose in the range of 50-400 mg. A single SC dose of 50, 200, and 400 mg or a single IV dose of 10 mg/kg was generally well tolerated.

Pharmacokinetics of macitentan in caucasian and Japanese subjects: the influence of ethnicity and sex.

BACKGROUND/AIMS: Macitentan is a novel dual endothelin receptor antagonist with sustained receptor binding in clinical development for pulmonary arterial hypertension. The present study compared the pharmacokinetics and safety of macitentan in healthy Caucasian and Japanese subjects and explored the potential sex differences. METHODS: In this single-center, open-label, phase I study 10 healthy subjects of each ethnic origin with a male/female ratio of 1:1 in each group were administered a single oral 10-mg dose of macitentan. Blood samples were taken to determine plasma levels of macitentan and its pharmacologically active metabolite, ACT-132577, and safety and tolerability were monitored using standard assessments. RESULTS: For both macitentan and its metabolite, values for Cmax were similar but a shorter half-life was determined in Japanese subjects resulting in an exposure to both compounds being approximately 15% lower in Japanese when compared to Caucasian subjects. The exposure to macitentan was similar in Japanese males and females whereas Caucasian females had an approximately 25% higher exposure than Caucasian males. In both ethnic groups, females had an approximately 15% higher exposure to ACT-132577 than male subjects. Macitentan was well tolerated in both ethnic groups. There were no clinically significant differences in adverse event profile, clinical laboratory, electrocardiographic parameters, and vital signs between both groups. CONCLUSION: The data suggest that the minor differences in pharmacokinetics between the two groups are not clinically relevant and no dose adjustment of macitentan based on Japanese ethnic origin or sex is necessary.

Pharmacokinetics and tolerability of almorexant in Japanese and Caucasian healthy male subjects.

BACKGROUND/AIMS: The aim of this study was to compare the pharmacokinetics and tolerability of single doses of the dual orexin receptor antagonist almorexant in Japanese and Caucasian healthy male subjects (n = 10 in each group, body weight matched ±5%). METHODS: Almorexant (200 mg) was administered in the morning in the fasted state. The pharmacokinetic parameters of almorexant were calculated by noncompartmental analysis from the plasma concentration data. RESULTS: The pharmacokinetics of almorexant in Japanese and Caucasian subjects were similar. The plasma concentration-time profile of almorexant was characterized by a rapid absorption and disposition. Peak plasma concentrations (C(max)) were reached at approximately 1.0 h in both ethnic groups. C(max) was 13% lower (ratio of geometric means [90% CI]: 0.87 [0.53, 1.43]), and the total exposure (AUC(0-)∞) was 15% lower (0.85 [0.54, 1.35]) in the Japanese subjects. There was no difference in the geometric mean ratio for t(1/2) between the two ethnic groups (1.03 [0.84, 1.25]). Almorexant was well tolerated in both ethnic groups. CONCLUSION: The pharmacokinetics and tolerability profiles of almorexant in Japanese and Caucasian healthy male subjects are similar. No dose adjustments for clinical studies with almorexant in Japanese subjects appear to be needed.

Concomitant or sequential administration of live attenuated Japanese encephalitis chimeric virus vaccine and yellow fever 17D vaccine: randomized double-blind phase II evaluation of safety and immunogenicity.

A randomized, double-blind, study was conducted to evaluate the safety, tolerability and immunogenicity of a live attenuated Japanese encephalitis chimeric virus vaccine (JE-CV) co-administered with live attenuated yellow fever vaccine (YF-17D strain; Stamaril®, Sanofi Pasteur) or administered successively. Participants (n = 108) were randomized to receive: YF followed by JE-CV 30 days later, JE followed by YF 30 days later, or the co-administration of JE and YF followed or preceded by placebo 30 days later or earlier. Placebo was used in a double-dummy fashion to ensure masking. Neutralizing antibody titers against JE-CV, YF-17D and selected wild-type JE strains was determined using a 50% serum-dilution plaque reduction neutralization test. Seroconversion was defined as the appearance of a neutralizing antibody titer above the assay cut-off post-immunization when not present pre-injection at day 0, or a least a four-fold rise in neutralizing antibody titer measured before the pre-injection day 0 and later post vaccination samples. There were no serious adverse events. Most adverse events (AEs) after JE vaccination were mild to moderate in intensity, and similar to those reported following YF vaccination. Seroconversion to JE-CV was 100% and 91% in the JE/YF and YF/JE sequential vaccination groups, respectively, compared with 96% in the co-administration group. All participants seroconverted to YF vaccine and retained neutralizing titers above the assay cut-off at month six. Neutralizing antibodies against JE vaccine were detected in 82-100% of participants at month six. These results suggest that both vaccines may be successfully co-administered simultaneously or 30 days apart.

Lot-to-lot consistency of a tetravalent dengue vaccine in healthy adults in Australia: a randomised study.

BACKGROUND: The recombinant yellow fever-17D-dengue virus, live, attenuated, tetravalent dengue vaccine (CYD-TDV) has undergone extensive clinical trials. Here safety and consistency of immunogenicity of phase III manufacturing lots of CYD-TDV were evaluated and compared with a phase II lot and placebo in a dengue-naïve population. METHODS: Healthy 18-60 year-olds were randomly assigned in a 3:3:3:3:1 ratio to receive three subcutaneous doses of either CYD-TDV from any one of three phase III lots or a phase II lot, or placebo, respectively in a 0, 6, 12 month dosing schedule. Neutralising antibody geometric mean titres (PRNT50 GMTs) for each of the four dengue serotypes were compared in sera collected 28 days after the third vaccination-equivalence among lots was demonstrated if the lower and upper limits of the two-sided 95% CIs of the GMT ratio were ≥0.5 and ≤2.0, respectively. RESULTS: 712 participants received vaccine or placebo and 614 (86%) completed the study; 17 (2.4%) participants withdrew after adverse events. Equivalence of phase III lots was demonstrated for 11 of 12 pairwise comparisons. One of three comparisons for serotype 2 was not statistically equivalent. GMTs for serotype 2 in phase III lots were close to each other (65.9, 44.1 and 58.1, respectively). CONCLUSIONS: Phase III lots can be produced in a consistent manner with predictable immune response and acceptable safety profile similar to previously characterised phase II lots. The phase III lots may be considered as not clinically different as statistical equivalence was shown for serotypes 1, 3 and 4 across the phase III lots. For serotype 2, although equivalence was not shown between two lots, the GMTs observed in the phase III lots were consistently higher than those for the phase II lot. As such, in our view, biological equivalence for all serotypes was demonstrated.

A phase 1 trial of MSP2-C1, a blood-stage malaria vaccine containing 2 isoforms of MSP2 formulated with Montanide® ISA 720.

BACKGROUND: In a previous Phase 1/2b malaria vaccine trial testing the 3D7 isoform of the malaria vaccine candidate Merozoite surface protein 2 (MSP2), parasite densities in children were reduced by 62%. However, breakthrough parasitemias were disproportionately of the alternate dimorphic form of MSP2, the FC27 genotype. We therefore undertook a dose-escalating, double-blinded, placebo-controlled Phase 1 trial in healthy, malaria-naïve adults of MSP2-C1, a vaccine containing recombinant forms of the two families of msp2 alleles, 3D7 and FC27 (EcMSP2-3D7 and EcMSP2-FC27), formulated in equal amounts with Montanide® ISA 720 as a water-in-oil emulsion. METHODOLOGY/PRINCIPAL FINDINGS: The trial was designed to include three dose cohorts (10, 40, and 80 µg), each with twelve subjects receiving the vaccine and three control subjects receiving Montanide® ISA 720 adjuvant emulsion alone, in a schedule of three doses at 12-week intervals. Due to unexpected local reactogenicity and concern regarding vaccine stability, the trial was terminated after the second immunisation of the cohort receiving the 40 µg dose; no subjects received the 80 µg dose. Immunization induced significant IgG responses to both isoforms of MSP2 in the 10 µg and 40 µg dose cohorts, with antibody levels by ELISA higher in the 40 µg cohort. Vaccine-induced antibodies recognised native protein by Western blots of parasite protein extracts and by immunofluorescence microscopy. Although the induced anti-MSP2 antibodies did not directly inhibit parasite growth in vitro, IgG from the majority of individuals tested caused significant antibody-dependent cellular inhibition (ADCI) of parasite growth. CONCLUSIONS/SIGNIFICANCE: As the majority of subjects vaccinated with MSP2-C1 developed an antibody responses to both forms of MSP2, and that these antibodies mediated ADCI provide further support for MSP2 as a malaria vaccine candidate. However, in view of the reactogenicity of this formulation, further clinical development of MSP2-C1 will require formulation of MSP2 in an alternative adjuvant. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry 12607000552482.

Phase 1 safety and immunogenicity trial of the Plasmodium falciparum blood-stage malaria vaccine AMA1-C1/ISA 720 in Australian adults.

A Phase 1 trial was conducted in malaria-naïve adults to evaluate the recombinant protein vaccine apical membrane antigen 1-Combination 1 (AMA1-C1) formulated in Montanide ISA 720 (SEPPIC, France), a water-in-oil adjuvant. Vaccinations were halted early due to a formulation issue unrelated to stability or potency. Twenty-four subjects (12 in each group) were enrolled and received 5 or 20 microg protein at 0 and 3 months and four subjects were enrolled and received one vaccination of 80 microg protein. After first vaccination, nearly all subjects experienced mild to moderate local reactions and six experienced delayed local reactions occurring at Day 9 or later. After the second vaccination, three subjects experienced transient grade 3 (severe) local reactions; the remainder experienced grade 1 or 2 local reactions. All related systemic reactogenicity was grade 1 or 2, except one instance of grade 3 malaise. Anti-AMA1-C1 antibody responses were dose dependent and seen following each vaccination, with mean antibody levels 2-3 fold higher in the 20 microg group compared to the 5 microg group at most time points. In vitro growth-inhibitory activity was a function of the anti-AMA1 antibody titer. AMA1-C1 formulated in ISA 720 is immunogenic in malaria-naïve Australian adults. It is reasonably tolerated, though some transient, severe, and late local reactions are seen.

Safety and immunogenicity of an oral inactivated whole-cell pseudomonas aeruginosa vaccine administered to healthy human subjects.

This study examines the safety and immunogenicity of an oral, whole-cell Pseudomonas aeruginosa vaccine administered to healthy volunteers. Thirty subjects received an oral dose of Pseudostat in two timed, measured doses with serological follow-up to 56 days postvaccination. Following vaccination, several individuals were identified as antibody responders for all three immunoglobulin (Ig) isotypes tested, specifically against whole-cell P. aeruginosa extract and outer membrane proteins F and I. The mean pooled lipopolysaccharide antigen-specific IgA showed the most significant and constant increases in titer postdose, with a similar increase in titer for whole-cell P. aeruginosa extract-specific IgA. The results demonstrated an increased phagocytic ability of the selected macrophage cell line in post vaccination sera. Furthermore a significant increase in intracellular macrophage killing of opsonized P. aeruginosa was also demonstrated (82% on day 14 postdose) in the presence of the postvaccination sera. The safety component of the study did not show any vaccine-attributable adverse effects in any of the subjects, as documented by clinical evidence, hematology, and biochemistry profiles. We conclude that Pseudostat is safe and immunogenic in humans at this dose and that further studies to determine the appropriate dosage and efficacy are needed. In our study, we have shown that the most significant and sustained responses to oral vaccination in human adult volunteers were serum IgA levels and that pooled sera collected postimmunization have an increased capacity to promote opsonophagocytotic killing of P. aeruginosa.