Phosphodiesterase-5 Inhibitor PF-03049423 Effect on Stroke Recovery: A Double-Blind, Placebo-Controlled Randomized Clinical Trial.

BACKGROUND: The therapeutic potential of phosphodiesterase-5 inhibitor PF-03049423 was evaluated in a phase 2, multicenter, randomized, double-blind, placebo-controlled study of subjects with acute ischemic stroke ( CLINICAL TRIAL REGISTRATION INFORMATION: http://www.clinicaltrials.gov, unique identifier: NCT01208233; http://www.clinicaltrialsregister.eu, EudraCT number: 2010-021414-32). MATERIALS AND METHODS: Subjects (N = 70) received PF-03049423 6 mg (or placebo, N = 67) once daily, orally, commencing between 24 and 78 hours of stroke onset, and continuing for 90 days. Postbaseline efficacy assessments were performed on Days 7, 14, 30, 60, and 90. Modified Rankin Scale (mRS), Barthel Index, National Institutes of Health Stroke Scale, Box and Blocks Test, Hand-Grip Strength Test, 10-Meter Walk Test, Repeatable Battery Assessment of Neuropsychological Status Naming and Coding Subtests, Line Cancellation Test, and Recognition Memory Test were administered to evaluate poststroke recovery. The primary endpoint was the mRS responder rate (score 0-2 at Day 90). The study included a planned interim analysis of efficacy data. RESULTS: The primary efficacy analysis using logistic regression showed no statistically significant difference between PF-03049423 6 mg and placebo (responder rate of 42.6% and 46.2%, respectively). Although PF-03049423 showed a satisfactory safety and tolerability profile, no signal of efficacy emerged from any of the outcome measures. CONCLUSIONS: PF-03049423 showed no therapeutic potential for acute ischemic stroke.

Vaccination with cancer- and HIV infection-associated endogenous retrotransposable elements is safe and immunogenic.

The expression of endogenous retrotransposable elements, including long interspersed nuclear element 1 (LINE-1 or L1) and human endogenous retrovirus, accompanies neoplastic transformation and infection with viruses such as HIV. The ability to engender immunity safely against such self-antigens would facilitate the development of novel vaccines and immunotherapies. In this article, we address the safety and immunogenicity of vaccination with these elements. We used immunohistochemical analysis and literature precedent to identify potential off-target tissues in humans and establish their translatability in preclinical species to guide safety assessments. Immunization of mice with murine L1 open reading frame 2 induced strong CD8 T cell responses without detectable tissue damage. Similarly, immunization of rhesus macaques with human LINE-1 open reading frame 2 (96% identity with macaque), as well as simian endogenous retrovirus-K Gag and Env, induced polyfunctional T cell responses to all Ags, and Ab responses to simian endogenous retrovirus-K Env. There were no adverse safety or pathological findings related to vaccination. These studies provide the first evidence, to our knowledge, that immune responses can be induced safely against this class of self-antigens and pave the way for investigation of them as HIV- or tumor-associated targets.

Nonreplicating vaccines can protect african green monkeys from the memphis 37 strain of respiratory syncytial virus.

BACKGROUND: We evaluated the immunological responses of African green monkeys immunized with multiple F and G protein-based vaccines and assessed protection against the Memphis 37 strain of respiratory syncytial virus (RSV). METHODS: Monkeys were immunized with F and G proteins adjuvanted with immunostimulatory (CpG) oligodeoxyribonucleotides admixed with either Alhydrogel or ISCOMATRIX adjuvant. Delivery of F and G proteins via replication incompetent recombinant vesicular stomatitis viruses (VSVs) and human adenoviruses was also evaluated. Mucosally or parenterally administered recombinant adenoviruses were used in prime-boost regimens with adjuvanted proteins or recombinant DNA. RESULTS: Animals primed by intranasal delivery of recombinant adenoviruses, and boosted by intramuscular injection of adjuvanted F and G proteins, developed neutralizing antibodies and F/G protein-specific T cells and were protected from RSV infection. Intramuscular injections of Alhydrogel (plus CpG) adjuvanted F and G proteins reduced peak viral loads in the lungs of challenged monkeys. Granulocyte numbers were not significantly elevated, relative to controls, in postchallenge bronchoalveolar lavage samples from vaccinated animals. CONCLUSIONS: This study has validated the use of RSV (Memphis 37) in an African green monkey model of intranasal infection and identified nonreplicating vaccines capable of eliciting protection in this higher species challenge model.

Phase 1 clinical study of an embryonic stem cell-derived retinal pigment epithelium patch in age-related macular degeneration.

Age-related macular degeneration (AMD) remains a major cause of blindness, with dysfunction and loss of retinal pigment epithelium (RPE) central to disease progression. We engineered an RPE patch comprising a fully differentiated, human embryonic stem cell (hESC)-derived RPE monolayer on a coated, synthetic basement membrane. We delivered the patch, using a purpose-designed microsurgical tool, into the subretinal space of one eye in each of two patients with severe exudative AMD. Primary endpoints were incidence and severity of adverse events and proportion of subjects with improved best-corrected visual acuity of 15 letters or more. We report successful delivery and survival of the RPE patch by biomicroscopy and optical coherence tomography, and a visual acuity gain of 29 and 21 letters in the two patients, respectively, over 12 months. Only local immunosuppression was used long-term. We also present the preclinical surgical, cell safety and tumorigenicity studies leading to trial approval. This work supports the feasibility and safety of hESC-RPE patch transplantation as a regenerative strategy for AMD.

Assessment of Cognitive and Neurologic Recovery in Ischemic Stroke Drug Trials: Results from a Randomized, Double-blind, Placebo-controlled Study.

Objective. Ischemic stroke is a serious medical condition with limited therapeutic options. The evaluation of the therapeutic potential of novel pharmacological interventions is carried-out in Phase II trials. The study design, primarily intended to evaluate efficacy and safety, is a balance between utilizing as few patients as possible to minimize safety risk and enrolling sufficient patients to detect unambiguous efficacy signals. We sought to determine whether post-stroke recovery outcomes based on behavioral measures of cognitive and motor impairment yielded additional information beyond that of clinician-based methods. Design. This was a multicenter, multinational, randomized, parallel group, controlled versus placebo, efficacy, and safety study of PF-03049423 for treatment of acute ischemic stroke. Settings and participants. Our study subjects were acute ischemic stroke inpatients. Measurements. Outcome measures were derived from rating scales (Modified Rankin Scale, Barthel Index, and National Institutes of Health Stroke Scale) and behavioral tests (Box and Blocks Test, Hand Grip Strength Test, 10-Meter Walk Test, Repeatable Battery Assessment of Neuropsychological Status Naming and Coding Subtests, Line Cancellation Test, and Recognition Memory Test). Assessments were performed at Days 7, 14, 30, 60, and 90. Post-hoc analyses of correlations among the outcome measures at each measurement time point on a cohort of 137 subjects were conducted. Results. Results support the validity of measures from Box and Blocks Test, Hand Grip Strength Test, 10-Meter Walk Test, and Repeatable Battery Assessment of Neuropsychological Status Coding Subtests to monitor post-stroke recovery in clinical trial settings. Notably, the Recognition Memory Test did not show a correlation with the Modified Rankin Scale, and, in fact, did not show improvement over time. Conclusion. The behavioral measures of cognitive and motor functions included in this study may extend the evaluation of the therapeutic potential of new treatments for stroke recovery. The lack of correlation between Recognition Memory Test and the traditional efficacy endpoints, at least in part due to absence of any improvement in recognition memory, suggests that there may be cognitive elements not detected by the Modified Rankin Scale. This is clinically relevant and memory improvement has potential as an endpoint in future trials aiming to improve certain aspects of cognition.

Acute kidney injury observed during phase 1 clinical trials of a novel xanthine oxidase/URAT1 dual inhibitor PF-06743649.

The objective of these clinical studies was to assess the safety and urate lowering activity of a novel urate transporter 1 (URAT1)/ xanthine oxidase (XO) inhibitor PF-06743649 in healthy subjects and gout patients. Escalating doses of PF-06743649 or placebo were given to healthy young subjects, healthy elderly subjects and gout patients. Serum uric acid (sUA) and urinary pharmacodynamic markers were assayed, and safety was assessed by collection of adverse events and assessment of safety labs, ECGs and vital signs. Administration of PF-06743649 led to rapid decrease in sUA in all cohorts; in gout patients, a change from baseline of 69 % was observed for the 40 mg dose. Urinary and serum biomarkers were consistent with inhibition of both URAT1 and XO. Although dosing was otherwise well tolerated, two subjects experienced serious adverse events of acute kidney injury. Both subjects exhibited increased serum creatinine and blood urea nitrogen in the first 3 days post first dose and were hospitalised. One subject exhibited oliguria for the first 24 h. Both subjects made a complete recovery with minimal intervention. PF-06743649 was effective at rapidly lowering sUA, but further development was terminated for an identified renal safety risk.

Development of vaccines to help treat drug dependence.

The social and economic consequences of drug addiction are immense. Although many methods are adopted to treat addiction, including therapeutic intervention and counseling, the long-term success rate has been limited and there continues to be a need for more effective treatments. A novel approach that has sparked a significant degree of interest recently is the use of vaccines designed to raise specific antibodies against drugs of abuse. Antibodies that prevent addictive substances crossing the blood-brain barrier may prove to be an effective mechanism that will help prevent relapse during efforts to abstain from the drug. Proof-of-principle for this approach has been established in numerous animal models. Currently a cocaine vaccine is in phase II clinical trials and, more recently, two vaccines to nicotine have entered phase I trials. Key efficacy trials are required to establish the true potential of these therapeutic vaccines.

Side-by-side comparison of gene-based smallpox vaccine with MVA in nonhuman primates.

Orthopoxviruses remain a threat as biological weapons and zoonoses. The licensed live-virus vaccine is associated with serious health risks, making its general usage unacceptable. Attenuated vaccines are being developed as alternatives, the most advanced of which is modified-vaccinia virus Ankara (MVA). We previously developed a gene-based vaccine, termed 4pox, which targets four orthopoxvirus antigens, A33, B5, A27 and L1. This vaccine protects mice and non-human primates from lethal orthopoxvirus disease. Here, we investigated the capacity of the molecular adjuvants GM-CSF and Escherichia coli heat-labile enterotoxin (LT) to enhance the efficacy of the 4pox gene-based vaccine. Both adjuvants significantly increased protective antibody responses in mice. We directly compared the 4pox plus LT vaccine against MVA in a monkeypox virus (MPXV) nonhuman primate (NHP) challenge model. NHPs were vaccinated twice with MVA by intramuscular injection or the 4pox/LT vaccine delivered using a disposable gene gun device. As a positive control, one NHP was vaccinated with ACAM2000. NHPs vaccinated with each vaccine developed anti-orthopoxvirus antibody responses, including those against the 4pox antigens. After MPXV intravenous challenge, all control NHPs developed severe disease, while the ACAM2000 vaccinated animal was well protected. All NHPs vaccinated with MVA were protected from lethality, but three of five developed severe disease and all animals shed virus. All five NHPs vaccinated with 4pox/LT survived and only one developed severe disease. None of the 4pox/LT-vaccinated animals shed virus. Our findings show, for the first time, that a subunit orthopoxvirus vaccine delivered by the same schedule can provide a degree of protection at least as high as that of MVA.

The efficacy of HSV-2 vaccines based on gD and gB is enhanced by the addition of ICP27.

DNA vaccines expressing HSV-2 gD, gB, ICP27, VP22 and VP13/14 were shown to be immunogenic in mice; gD and gB elicited neutralising antibody, and all five antigens induced T cell responses measured by IFNγ ELISPOT. In murine HSV-2 challenge studies, gD and gB provided moderate to high levels of protection while ICP27 provided a lower level of protection depending on the model (intravaginal or intranasal) and the challenge dose. Combining vaccines expressing gB or gD with vaccines expressing ICP27 provided greater protection than any antigen alone. We conclude that the addition of ICP27 to enhance the anti-viral T cell response can improve the efficacy of gD- and gB-based vaccines.

HERV-K-specific T cells eliminate diverse HIV-1/2 and SIV primary isolates.

The genetic diversity of HIV-1 represents a major challenge in vaccine development. In this study, we establish a rationale for eliminating HIV-1-infected cells by targeting cellular immune responses against stable human endogenous retroviral (HERV) antigens. HERV DNA sequences in the human genome represent the remnants of ancient infectious retroviruses. We show that the infection of CD4+ T cells with HIV-1 resulted in transcription of the HML-2 lineage of HERV type K [HERV-K(HML-2)] and the expression of Gag and Env proteins. HERV-K(HML-2)-specific CD8+ T cells obtained from HIV-1-infected human subjects responded to HIV-1-infected cells in a Vif-dependent manner in vitro. Consistent with the proposed mode of action, a HERV-K(HML-2)-specific CD8+ T cell clone exhibited comprehensive elimination of cells infected with a panel of globally diverse HIV-1, HIV-2, and SIV isolates in vitro. We identified a second T cell response that exhibited cross-reactivity between homologous HIV-1-Pol and HERV-K(HML-2)-Pol determinants, raising the possibility that homology between HIV-1 and HERVs plays a role in shaping, and perhaps enhancing, the T cell response to HIV-1. This justifies the consideration of HERV-K(HML-2)-specific and cross-reactive T cell responses in the natural control of HIV-1 infection and for exploring HERV-K(HML-2)-targeted HIV-1 vaccines and immunotherapeutics.

Single and combination herpes simplex virus type 2 glycoprotein vaccines adjuvanted with CpG oligodeoxynucleotides or monophosphoryl lipid A exhibit differential immunity that is not correlated to protection in animal models.

Despite several attempts to develop an effective prophylactic vaccine for HSV-2, all have failed to show efficacy in the clinic. The most recent of these failures was the GlaxoSmithKline (GSK) subunit vaccine based on the glycoprotein gD with the adjuvant monophosphoryl lipid A (MPL). In a phase 3 clinical trial, this vaccine failed to protect from HSV-2 disease, even though good neutralizing antibody responses were elicited. We aimed to develop a superior, novel HSV-2 vaccine containing either gD or gB alone or in combination, together with the potent adjuvant CpG oligodeoxynucleotides (CPG). The immunogenic properties of these vaccines were compared in mice. We show that gB/CPG/alum elicited a neutralizing antibody response similar to that elicited by gD/CPG/alum vaccine but a significantly greater gamma interferon (IFN-γ) T cell response. Furthermore, the combined gB-gD/CPG/alum vaccine elicited significantly greater neutralizing antibody and T cell responses than gD/MPL/alum. The efficacies of these candidate vaccines were compared in the mouse and guinea pig disease models, including a novel male guinea pig genital disease model. These studies demonstrated that increased immune response did not correlate to improved protection. First, despite a lower IFN-γ T cell response, the gD/CPG/alum vaccine was more effective than gB/CPG/alum in mice. Furthermore, the gB-gD/CPG/alum vaccine was no more effective than gD/MPL/alum in mice or male guinea pigs. We conclude that difficulties in correlating immune responses to efficacy in animal models will act as a deterrent to researchers attempting to develop effective HSV vaccines.

GM-CSF increases mucosal and systemic immunogenicity of an H1N1 influenza DNA vaccine administered into the epidermis of non-human primates.

BACKGROUND: The recent H5N1 avian and H1N1 swine-origin influenza virus outbreaks reaffirm that the threat of a world-wide influenza pandemic is both real and ever-present. Vaccination is still considered the best strategy for protection against influenza virus infection but a significant challenge is to identify new vaccine approaches that offer accelerated production, broader protection against drifted and shifted strains, and the capacity to elicit anti-viral immune responses in the respiratory tract at the site of viral entry. As a safe alternative to live attenuated vaccines, the mucosal and systemic immunogenicity of an H1N1 influenza (A/New Caledonia/20/99) HA DNA vaccine administered by particle-mediated epidermal delivery (PMED or gene gun) was analyzed in rhesus macaques. METHODOLOGY/PRINCIPAL FINDINGS: Macaques were immunized at weeks 0, 8, and 16 using a disposable single-shot particle-mediated delivery device designed for clinical use that delivers plasmid DNA directly into cells of the epidermis. Significant levels of hemagglutination inhibiting (HI) antibodies and cytokine-secreting HA-specific T cells were observed in the periphery of macaques following 1-3 doses of the PMED HA DNA vaccine. In addition, HA DNA vaccination induced detectable levels of HA-specific mucosal antibodies and T cells in the lung and gut-associated lymphoid tissues of vaccinated macaques. Importantly, co-delivery of a DNA encoding the rhesus macaque GM-CSF gene was found to significantly enhance both the systemic and mucosal immunogenicity of the HA DNA vaccine. CONCLUSIONS/SIGNIFICANCE: These results provide strong support for the development of a particle-mediated epidermal DNA vaccine for protection against respiratory pathogens such as influenza and demonstrate, for the first time, the ability of skin-delivered GM-CSF to serve as an effective mucosal adjuvant for vaccine induction of immune responses in the gut and respiratory tract.

DNA vaccination protects against an influenza challenge in a double-blind randomised placebo-controlled phase 1b clinical trial.

BACKGROUND: We have developed a Trivalent DNA vaccine for influenza consisting of three plasmids expressing haemagglutinin from different seasonal influenza virus strains delivered using PMED (particle mediated epidermal delivery). We set out to determine whether this vaccine (with and without a molecular adjuvant DNA Encoded Immunostimulator-Labile Toxin (DEI-LT)) could protect subjects from a controlled influenza virus challenge. METHODS: Healthy adult subjects were screened for susceptibility to infection with influenza A/H3 Panama/2007/99 then vaccinated with 4microg Trivalent influenza DNA vaccine, 2microg Trivalent influenza DNA vaccine plus DEI-LT or placebo. Safety and serological responses to vaccination were assessed and on Day 56 subjects were challenged with A/H3 Panama/2007/99 virus. RESULTS: Vaccination with 4microg Trivalent or 2microg Trivalent/DEI-LT was well tolerated and induced antibody responses to two of the three influenza virus vaccine strains. Post challenge, subjects in the 4microg Trivalent group (N=27) showed reductions in disease symptoms and viral shedding compared to placebo (N=27), with an overall vaccine efficacy of 41% (95% confidence interval (CI)=?1.5, 67.7) for 'Any illness with or without fever' and 53% for 'Upper respiratory tract infection' (95% CI=8.0, 77.7). CONCLUSION: It was concluded that PMED vaccination with 4microg Trivalent influenza DNA vaccine was safe and elicited immunological responses that protected human subjects from influenza; this is the first report of protection of human subjects from disease by DNA vaccination.

Preclinical evaluation of DISC-GMCSF for the treatment of breast carcinoma.

BACKGROUND: DISC-hGMCSF is a gH-deleted HSV-2 based vector expressing human GM-CSF that has entered clinical trials for the therapy of metastatic melanoma. To determine whether this product also has potential to treat breast carcinoma, a series of in vitro and in vivo studies were made. METHODS: Breast carcinoma cell lines and primary cultures of breast carcinoma cells were infected with DISC-GFP or DISC-human-GMCSF (DISC-hGMCSF) and the number of GFP-positive cells and GM-CSF yields were determined. In vivo efficacy of DISC-murine-GMCSF (DISC-mGMCSF) in combination with systemic chemotherapy was assessed in the murine 4T1 breast carcinoma model by direct injection into subcutaneous tumours. RESULTS: DISC-hGMCSF was able to infect all breast carcinoma cell lines and the majority of primary breast carcinoma cultures with high efficiency, although culture-to-culture variability in infectability was noted in the latter. In the MCF-7 breast carcinoma cell line, expression of hGMCSF was found to peak over the first 24 h post-infection and drop to background levels by 7 to 14 days. In the 4T1 murine breast tumour model, injection of subcutaneous tumours led to a delay in tumour growth and, in rare cases, complete regression of visible tumour. DISC-mGMCSF and DISC-LacZ showed similar levels of efficacy. When mice were given simultaneous 5FU chemotherapy the effectiveness of DISC-mGMCSF treatment was undiminished, and up to three out of ten mice showed complete absence of visible tumour. CONCLUSIONS: DISC-hGMCSF is able to infect human breast carcinoma cells at high efficiency and express GM-CSF. DISC-mGMCSF demonstrated efficacy in the murine 4T1 model, even during concomitant chemotherapy. Taken together these results indicate that DISC-hGMCSF may have potential for the treatment of breast carcinoma.