A Phase 1 study of the safety, pharmacokinetics and anti-leukemic activity of the anti-CD123 monoclonal antibody CSL360 in relapsed, refractory or high-risk acute myeloid leukemia.

Acute myeloid leukemia (AML) blasts express high levels of interlekin-3 (IL-3) receptor-α (CD123). CSL360 is a recombinant, chimeric immunoglobulin G1 (IgG1), anti-CD123 monoclonal antibody (MoAb) that neutralizes IL-3 and demonstrates anti-leukemic activity in vitro. This phase 1 study assessed safety, pharmacokinetics and bioactivity of weekly intravenous CSL360 for 12 weeks in 40 patients with advanced AML across five dose levels (0.1-10.0 mg/kg). Other than mild infusion reactions, CSL360 was well tolerated. The maximal tolerated dose was not reached. The half-life was 4.9 days, and the area under the curve (AUC) and maximum concentration (Cmax) increased proportionally with dose. Doses ≥ 3.0 mg/kg resulted in complete saturation and down-regulation of CD123 and abolition of ex vivo proliferative responsiveness to IL-3, indicating adequate blockade of IL-3 signaling. Two patients responded, with one remaining in complete remission after 17 doses. CSL360 bound CD123 specifically, but did not induce anti-leukemic activity in most patients. While safe, MoAb blockade of CD123 function is insufficient as a therapeutic strategy.

Evaluation of the bioactivity of influenza vaccine strains in vitro suggests that the introduction of new strains in the 2010 Southern Hemisphere trivalent influenza vaccine is associated with adverse events.

In Australia, during the 2010 Southern Hemisphere (SH) influenza season, there was an unexpected increase in post-marketing adverse event reports of febrile seizures (FS) in children under 5 years of age shortly after vaccination with the CSL trivalent influenza vaccine (CSL 2010 SH TIV) compared to previous CSL TIVs and other licensed 2010 SH TIVs. The present study describes the outcomes of a series of in vitro experiments directed at elucidating the root cause. The scientific investigations found that a subset of paediatric donors displayed elevated cytokine/chemokine responses to the CSL 2010 SH TIV but not to previous CSL TIVs nor other 2010 SH TIVs. The induction of elevated cytokines/chemokines in paediatric whole blood correlated with elevated NF-κB activation in a HEK293 cell reporter assay. The data indicate that the introduction of the B/Brisbane/60/2008 strain within the CSL manufacturing process (such as occurred in the preceding 2009/10 NH season) appears to have raised the pyrogenic potential of the CSL 2009/10 NH TIV but that this was insufficient to elicit FS in children <5 years. The 2010 SH season coincided with the first introduction of the H1N1 A/California/07/2009 in combination with the B/Brisbane/60/2008 strain. Our data demonstrates that the introduction of the H1N1 A/California/07/2009 (and to a much lesser degree, H3N2 A/Wisconsin/15/2009) in combination with B/Brisbane/60/2008 (as expressed through the CSL method of manufacture) combined and likely compounded the bioactivity of the CSL 2010 SH TIV. This was associated with stronger immune responses, which in a proportion of children <5 years were associated with FS. The assays and systems developed during these investigations should greatly assist in determining the bioactivity of new influenza strains, and thus aid with the manufacture of CSL TIVs indicated for use in the paediatric population.

Role of viral RNA and lipid in the adverse events associated with the 2010 Southern Hemisphere trivalent influenza vaccine.

In Australia, during the 2010 Southern Hemisphere (SH) influenza season, there was an unexpected increase in post-marketing adverse event reports of febrile seizures (FS) in children under 5 years of age shortly after vaccination with the CSL 2010 SH trivalent influenza vaccine (CSL 2010 SH TIV) compared to previous CSL TIVs and other licensed 2010 SH TIVs. In an accompanying study, we described the contribution to these adverse events of the 2010 SH influenza strains as expressed in the CSL 2010 SH TIV using in vitro cytokine/chemokine secretion from whole blood cells and induction of NF-κB activation in HEK293 reporter cells. The aim of the present study was to identify the root cause components that elicited the elevated cytokine/chemokine and NF-κB signature. Our studies demonstrated that the pyrogenic signal was associated with a heat-labile, viral-derived component(s) in the CSL 2010 SH TIV. Further, it was found that viral lipid-mediated delivery of short, fragmented viral RNA was the key trigger for the increased cytokine/chemokine secretion and NF-κB activation. It is likely that the FS reported in children <5 years were due to a combination of the new influenza strains included in the 2010 SH TIV and the CSL standard method of manufacture preserving strain-specific viral components of the new influenza strains (particularly B/Brisbane/60/2008 and to a lesser extent H1N1 A/California/07/2009). These combined to heighten immune activation of innate immune cells, which in a small proportion of children <5 years of age is associated with the occurrence of FS. The data also demonstrates that CSL TIVs formulated with increased levels of splitting agent (TDOC) for the B/Brisbane/60/2008 strain can attenuate the pro-inflammatory signals in vitro, identifying a potential path forward for generating a CSL TIV indicated for use in children <5 years.

Scientific investigations into febrile reactions observed in the paediatric population following vaccination with a 2010 Southern Hemisphere Trivalent Influenza Vaccine.

During the 2010 Southern Hemisphere (SH) influenza season, there was an unexpected increase in the number of febrile reactions reported in the paediatric population in Australia shortly after vaccination with the CSL 2010 trivalent influenza vaccine (TIV) compared to previous seasons. A series of scientific investigations were initiated to identify the root cause of these adverse events, including in vitro cytokine/chemokine assays following stimulation of adult and paediatric whole blood, as well as mammalian cell lines and primary cells, profiling of molecular signatures using microarrays, and in vivo studies in rabbits, ferrets, new born rats and rhesus non-human primates (NHPs). Various TIVs (approved commercial vaccines as well as re-engineered TIVs) and their individual monovalent pool harvest (MPH) components were examined in these assays and in animal models. Although the scientific investigations are ongoing, the current working hypothesis is that the increase in febrile adverse events reported in Australia after vaccination with the CSL 2010 SH TIV may be due to a combination of both the introduction of three entirely new strains in the CSL 2010 SH TIV, and differences in the manufacturing processes used to manufacture CSL TIVs compared to other licensed TIVs on the market. Identification of the causal component(s) may result in the identification of surrogate assays that can assist in the formulation of TIVs to minimise the future incidence of febrile reactions in the paediatric population.

A randomized, placebo-controlled, dose-escalation study to determine the safety, tolerability, and immunogenicity of an HPV-16 therapeutic vaccine in HIV-positive participants with oncogenic HPV infection of the anus.

OBJECTIVE: Study aimed to assess safety, tolerability, and immunogenicity of novel therapeutic HPV-16 E6E7 ISCOMATRIX vaccine for treatment of human papilloma virus (HPV)-related anal intraepithelial neoplasia in HIV-infected men who have sex with men with moderate immunosuppression. DESIGN: Randomized, multicenter, blinded, placebo-controlled, dose-escalating study investigating 3 different doses of vaccine and different dose schedule. Primary objective to determine safety and tolerability, including clinical status, maintenance of virological control, and CD4 cell count for more than 252 days. RESULTS: Thirty-five men who have sex with men enrolled; median age 47 years; current CD4 count 627 cells per milliliter; nadir CD4 count 154 cells per milliliter; 94% current antiretrovirals; 100% high-risk HPV types; 69% abnormal anal cytology; and 34% anal intraepithelial neoplasia 1-3 on high-resolution anoscopy. No dose-limiting toxicities or serious adverse events in HPV-16 vaccine recipients. Most HPV-16 vaccine recipients reported moderate/severe short-term injection site reactions and systemic reactions including headache, myalgia, and fatigue. CD4 cell counts remained stable. Five participants had transiently detectable viral loads. Ninety-six percent of vaccine recipients had at least a 4-fold increase in HPV-16 antibody from prevaccination levels. Seventy-one percent had at least a 3-fold increase in interferon-gamma responses to E6E7 peptides. CONCLUSIONS: The novel therapeutic HPV-16 E6E7 ISCOMATRIX vaccine seemed safe and reasonably well tolerated. The therapeutic vaccine induces strong and durable antibody responses and moderate interferon-gamma levels that fell to prevaccination levels by week 24.

Priming of CD4+ and CD8+ T cell responses using a HCV core ISCOMATRIX vaccine: a phase I study in healthy volunteers.

The disease burden and public health impact of chronic HCV infection continues to be a major problem globally. Current treatment for chronic HCV infection is not effective in all patients and is frequently associated with unacceptable side effects. Clearly a need exists for improved treatments and one such strategy is the use of therapeutic vaccines. Although still not completely understood, emerging data indicate that the generation of CD4(+) and CD8(+) T cells are important for the clearance of HCV. We have developed a prototype vaccine with the HCV Core protein and ISCOMATRIX adjuvant (HCV Core ISCOMATRIX vaccine). ISCOMATRIX vaccines have been shown to induce CD4(+) and CD8(+) T cell responses to a range of antigens in both animal models and in human studies. Additionally, ISCOMATRIX vaccines have been shown to be safe and generally well tolerated in several clinical trials. Preliminary studies demonstrated that the prototype HCV Core ISCOMATRIX vaccine induced strong CD4(+) and CD8(+) T cell responses in monkeys following immunization. Here we show the results of a Phase I placebo controlled, dose escalation clinical study designed to evaluate the safety, tolerability and immunogenicity of the HCV Core ISCOMATRIX vaccine in healthy individuals. The 30 subjects received three immunizations of HCV Core ISCOMATRIX vaccines or placebo vaccine on days 0, 28 and 56. The HCV Core ISCOMATRIX vaccines contained 5, 20 or 50 microg HCV Core protein with 120 mug ISCOMATRIX adjuvant. The adverse events reported were generally mild to moderate in severity, of short duration and self-limiting. The most common adverse events were injection site reactions such as pain and redness as well as myalgia. Antibody responses were detected in all but one of the participants receiving the HCV Core ISCOMATRIX vaccine and there was no indication of a dose response. CD8(+) T cell responses were only detected in two of the eight participants receiving the highest dose. T cell cytokines were detected in 7 of the 8 participants in the highest dose group. The results of this study support the further evaluation of this prototype HCV Core ISCOMATRIX vaccine in HCV infected subjects.