Lawrence Segal

Non-clinical safety and biodistribution of AS03-adjuvanted inactivated pandemic influenza vaccines.

Pandemic‐influenza vaccines containing split‐inactivated‐virus antigen have been formulated with the immunostimulatory Adjuvant System AS03 to enhance the antigen immunogenicity and reduce antigen content per dose. AS03 is an oil‐in‐water emulsion containing α‐tocopherol, squalene and polysorbate 80. To support the clinical development of AS03‐adjuvanted pandemic‐influenza vaccines, the local and systemic toxicity of test articles containing split‐influenza A(H5N1) and/or AS03 were evaluated after 3–4 intramuscular (i.m.) injections in rabbits. Treatment‐related effects were restricted to mild inflammatory responses and were induced primarily by the test articles containing AS03. The injection‐site inflammation was mild at 3 days, and minimal at 4 weeks after the last injection; and was reflected by signs of activation in the draining lymph nodes and by systemic effects in the blood including a transient increase of neutrophils. In addition, a study in mice explored the biodistribution of A(H5N1) vaccines or AS03 through radiolabelling the antigen or constituents of AS03 prior to injection. In this evaluation, 57–73% of AS03s principal constituents had cleared from the injection site 3 days after injection, and their different clearance kinetics were suggestive of AS03s dissociation. All these AS03 constituents entered into the draining lymph nodes within 30 min after injection. In conclusion, the administration of repeated doses of the H5N1/AS03 vaccine was well tolerated in the rabbit, and was primarily associated with transient mild inflammation at the injection site and draining lymph nodes. The biodistribution kinetics of AS03 constituents in the mouse were consistent with AS03 inducing this pattern of inflammation. Copyright

Cutaneous Toxicity of Surfactants in Normal Human Keratinocytes Assessed by Cytotoxicity, Arachidonic Acid Release, and Regulation of Interleukin-lα mRNA

Development and validation of in vitro methods for cutaneous irritation testing is aimed at establishing simple and reliable assays that eliminate the need for animals in toxicity testing. It is therefore important to identify in vitro end points that are predictive of in vivo toxicity. Identification of proinflamma-tory mediators and cytokines in keratinocytes may represent an early event in cutaneous inflammation. Three end points were evaluated: cytotoxicity [(crystal violet staining (CVS)], the release of [3H]arachidonic acid (AAR), and the regulation of the proinflammatory cytokine interleukin-1α (IL-lα) message in keratinocytes as a potential in vitro assay for surfactants. Cultured normal human epidermal keratinocytes were treated with various concentrations of three surfactants (SDS, Triton X-100, and Tween 20) of different in vivo potencies. The CVS50 1 h (surfactant concentrations yielding 50% viability) and AAR50 (surfactant concentrations causing 50% release of labelled arachidonic acid), both...

Local tolerance and systemic toxicity of single and repeated intramuscular administrations of two different formulations of the RTS,S malaria candidate vaccine in rabbits

RTS,S malaria antigen is weakly immunogenic as such and needs to be formulated with an adjuvant to improve the magnitude and duration of the immune responses to RTS,S. Two Adjuvant Systems, AS01 and AS02 were evaluated during the development of the RTS,S vaccine. The evaluation included non-clinical studies in rabbits to evaluate the local intramuscular tolerance following administration on a single occasion, and the local and systemic effects following repeated administrations of RTS,S/AS01 or RTS,S/AS02 formulations. In the first study, rabbits were injected on one occasion with RTS,S/AS01, RTS,S/AS02 or controls, and the local intramuscular tolerance was evaluated up to 3 days after injection. In the second study, the different formulations were injected on Days 0, 14, 28 and 42. General health status, haematology and blood chemistry parameters were monitored on a regular basis. Macroscopic and microscopic evaluations were made after termination of the study. No sign of toxicity was detected following single or repeated administrations of the adjuvanted RTS,S formulations. Changes in haematology or clinical chemistry parameters were indicative of a developing immune response in the groups receiving either RTS,S formulation. All examined parameters returned to normal within 28 days after the last injection. The absence of toxicological effects following the injection of RTS,S/AS01 or RTS,S/AS02 in rabbits was supportive of further clinical evaluation of these two formulations.

Non‐clinical safety assessment of single and repeated intramuscular administration of a human papillomavirus‐16/18 vaccine in rabbits and rats

The human papillomavirus (HPV)‐16/18 vaccine (Cervarix®) is a prophylactic vaccine for the prevention of cervical cancer. The vaccine contains recombinant virus‐like particles assembled from the L1 major capsid proteins of the cervical cancer‐causing viral types HPV‐16 and HPV‐18, and Adjuvant System 04 (AS04), which contains the immunostimulant MPL and aluminium salt. To evaluate potential local and systemic toxic effects of the HPV‐16/18 vaccine or AS04 alone, three repeated‐dose studies were performed in rabbits and rats. One rabbit study also included a single‐dose evaluation. In rabbits (~2.5 kg), the full human dose (HD) of the vaccine was evaluated (0.5 ml per injection site), and in rats (~250 g), 1/5 HD of vaccine was evaluated, corresponding to ≥ 12 times the dosage in humans relative to body weight. In both animal models, the treatment‐related changes included a slight transient increase in the number of circulating neutrophils as well as a local inflammatory reaction at the injection site. These treatment‐related changes were less pronounced after four doses of AS04 alone than after four doses of the HPV‐16/18 vaccine. Additional treatment‐related changes in the rat included lower albumin/globulin ratios and microscopic signs of inflammation in the popliteal lymph nodes. In both animal models, 13 weeks after the fourth dose, recovery was nearly complete, although at the injection site in some animals there were signs of discoloration, muscle‐fibre regeneration and focal points of macrophage infiltration. Therefore, in these non‐clinical models, the single and repeated dose administrations of the HPV‐16/18 vaccine or AS04 alone were safe and well tolerated. Copyright

Non-clinical safety assessment of single and repeated administration of gE/AS01 zoster vaccine in rabbits

HZ/su is an investigational recombinant subunit vaccine for the prevention of shingles, a disease resulting from the reactivation of varicella zoster virus. The vaccine is composed of recombinant varicella zoster virus glycoprotein E (gE), and liposome‐based Adjuvant System AS01. To evaluate the potential local and systemic effects of this vaccine, three studies were performed in rabbits. In the first two studies, rabbits received a single intramuscular (IM; study 1) or subcutaneous (SC; study 2) dose of gE/AS01, AS01 alone (in study 2 only) or saline, and the local tolerance was evaluated up to 3 days after administration. Under these conditions, only local inflammatory reactions at the injection sites were detected by microscopic evaluation. In the third study, gE/AS01, AS01 alone or saline, were injected SC or IM on four occasions at 2 week intervals. General health status, local tolerance, ophthalmology, haematology and blood chemistry parameters were monitored. Macroscopic and microscopic evaluations were performed after termination of the study. The only treatment‐related changes included a transient increase in neutrophils, C‐reactive protein and fibrinogen levels and microscopic signs of inflammation at the injection sites, which are expected observations related to the elicited inflammatory reaction. The SC and IM routes of administration produced similar systemic effects. However, microscopic findings at the injection sites differed. One month after the last injection, recovery was complete in all groups. In conclusion, the single and repeated SC and IM administration of the gE/AS01 vaccine were locally and systemically well‐tolerated in rabbits and support the clinical development of the vaccine. Copyright

Effects of Adjuvant Systems on the cardiovascular and respiratory functions in telemetered conscious dogs and anaesthetised rats

Adjuvants Systems (AS) containing immunostimulant combinations are used in human vaccines. Safety pharmacology studies evaluated the cardiorespiratory effects of AS in conscious telemetered dogs and in anaesthetised rats. Sixteen telemetered beagle dogs (4/group) received intramuscular injections of saline at Day 0, and one clinical dose of AS01, AS03, AS04 or AS15 at Day 7 (7× the equivalent human dose on a bodyweight basis). Bodyweights were measured through Day 14 and cardiorespiratory parameters and body temperature through 72 h post-treatment. Anaesthetised rats (4/group) received one intravenous injection of AS01, AS03 or AS15 at 1 mL/kg bodyweight (140× the equivalent human dosages), or saline. Cardiorespiratory parameters were measured for 120 min post-dose. In dogs, food consumption and mean bodyweight decreased with AS03, and mean body temperature slightly increased with AS01, AS03 and AS15, but were not considered to be adverse. Cardiovascular effects (a slight, reversible increase in mean heart rate and shortened mean RR/PR/QT-intervals) were observed with AS15. No relevant clinical effects or effects on QRS-complex/QTc-interval durations, arterial pressure or respiratory parameters were observed. In rats, there were no consistent treatment-related effects. Collectively, this suggests that AS01, AS03, AS04 and AS15 are not associated with potentially deleterious effects on ventricular repolarisation, atrio/intra-ventricular conductivities or respiratory functions.

Signal management in pharmacovigilance and human risk assessment of CpG 7909, integrating embryo-fetal and post-natal developmental toxicity studies in rats and rabbits

The potential reproductive and developmental toxicity of the synthetic oligodeoxynucleotide (ODN) CpG 7909, a component of GSKs AS15 immunostimulant, was examined in rat and rabbit studies following intermittent intramuscular injections. Previous studies using subcutaneous and intraperitoneal injections in mice, rats and rabbits revealed that CpG ODNs induced developmental effects. To analyze the safety signal, GSK conducted additional animal studies using the intended clinical route of administration. CpG 7909 injections were administered intramuscularly to rats or rabbits 28 and 14days before pairing, on 4 or 5 occasions during gestation, and on lactation day 7. The No Observed Adverse Effect Level for female fertility, embryo-fetal and pre- and post-natal development was 4.2mg/kg in both species, approximately 500-fold higher than the anticipated human dose. In conclusion, the anticipated risk to humans is considered low for sporadic intramuscular exposure to CpG 7909.

Intramuscularly administered herpes zoster subunit vaccine has no effects on fertility, pre- and post-natal development in Sprague-Dawley rats

The herpes zoster subunit vaccine (HZ/su) is an investigational vaccine for the prevention of shingles, a disease caused by the varicella zoster virus (VZV). It is composed of recombinant VZV glycoprotein E (gE) and AS01. We assessed the potential toxic effects of gE/AS01 and AS01 alone on female and male fertility, and on embryo-fetal, pre- and post-natal development in Sprague-Dawley rats. Females were immunized before pairing and during gestation. Half of the pregnant rats were used for embryo-fetal investigations. The ones that gave birth were immunized during lactation and offspring were analysed. In a male fertility study, rats were immunized before pairing. After mating, the untreated females were sacrificed and the fetuses examined. In addition, male fertility parameters were evaluated. Results indicated that female mating performance and fertility, pre- and post-natal survival and offspring development, male mating performance and fertility were unaffected by intramuscular administration of the zoster candidate vaccine gE/AS01.