Sustained Therapeutic Levels Research Articles

In Vivo Secretion of Bispecific Antibodies Recruiting Lymphocytic Effector Cells

Engineered Fc-lacking bispecific antibodies have shown an exceptionally high potency for recruiting lymphocyte effector cells and enhancing antitumor activity, which is under evaluation in several clinical trials. However, current treatment regimens raise some issues that should be considered, such as the high cost of clinical-grade bispecific antibodies and the achievement of sustained therapeutic plasma levels. The use of gene transfer methods may circumvent problems related to large-scale production and purification, and result in sustained therapeutic plasma concentrations of the Fc-lacking bispecific antibodies. In fact, terminally differentiated cells and non-terminally differentiated cells can be genetically modified to secrete functionally active bispecific antibodies exerting clear anti-tumor effects. This review highlights the relevance of different promising strategies for in vivo delivery of therapeutic bispecific antibodies.

Preparation and Evaluation of Novel Expandable Drug Delivery System

Aims: The purpose of this research is to develop a novel expandable gastroretentive dosage form (GRDF), based on unfolding mechanism. It consists of a drug loaded bilayer polymeric film, folded into a hard gelatin capsule. Gastric retention is achieved due to unfolding of the dosage form within 15-20 min. Furosemide is selected as the drug candidate for this work. Due to its narrow absorption window, Furosemide has to be administered to the upper parts of the intestine in order to maintain sustained therapeutic levels. This may be achieved by a GRDF. Methodology: Films were prepared by solvent-casting technique using Ethyl cellulose, HPMC E15 and Eudragit RLPO as polymers and dibutyl phthalate as the plasticizer in both layers. The film with zigzag folding in the capsule was shown to unfold in the gastric juice and provide drug release up to 12 h in the acidic medium. The films were evaluated for weight & thickness variation, mechanical properties, in vitro drug release and unfolding behavior based on the mechanical shape memory of polymers. Absence of drug polymer interaction and uniform drug dispersion in the polymeric layers was revealed by DSC, XRD studies and SEM. The GRDF location in the gastrointestinal tract was determined by X-ray studies. Results: X-ray studies revealed that the GRDF is retained in the stomach up to 6± 0.5 h in fasting condition and 8 h in fed state. Conclusion: The polymers used in the development of GRDFs were safe and proper combination of these polymers will yield a novel expandable GRDF with good in vitro drug release in acidic media, mechanical properties, and unfolding behaviour. These outcomes demonstrate that the GRDF may be used to improve furosemide therapy and can be applied to extend the absorption of other narrow absorption window drugs that require continuous input.

Target-Mediated Disposition Model Describing the Dynamics of IL12 and IFNγ after Administration of a Mifepristone-Inducible Adenoviral Vector for IL-12 Expression in Mice

Interleukin-12 (IL12) is a cytokine with potential applications in the treatment of cancer given the potent immune response that it triggers, in part due to its ability to stimulate expression of interferon-γ (IFNγ). To avoid the toxicity associated with systemic exposure to IL12, a high-capacity adenoviral vector carrying a liver-specific, mifepristone-inducible IL12 expression system (HC-Ad/RUmIL12) has been developed. However, the maintenance of IL12 expression at therapeutic levels is compromised by the inhibitory effect of IFNγ on inducible systems. The aim of this work is to develop a semi-mechanistic model to characterize the relationship between IL12 and IFNγ in wild-type and knock-out mice for the IFNγ receptor treated with HC-Ad/RUmIL12 under different dosing regimens in order to better understand the key mechanisms controlling the system. Rapid binding was considered to account for target-mediated disposition exhibited by both cytokines (equilibrium dissociation constant were 18 and 2.28pM for IL12 and IFNγ, respectively). The final model included: (1) IFNγ receptor turnover, (2) irreversible free cytokine elimination from the serum compartment, (3) internalization of the IL12 receptor complex, (4) IL12 expression upregulated by the co-administration of the adenoviral vector and mifepristone and downregulated by the IFNγ receptor, and (5) synthesis of IFNγ controlled by the relative increments in the bound IL12. In conclusion, a model simultaneously describing the kinetics of IL12 and IFNγ in the context of gene therapy was developed and validated with additional data. The model was applied to design an experimental dosing protocol intended to maintain sustained therapeutic IL12 levels.

Ribosomal DNA Integrating rAAV-rDNA Vectors Allow for Stable Transgene Expression

Although recombinant adeno-associated virus (rAAV) vectors are proving to be efficacious in clinical trials, the episomal character of the delivered transgene restricts their effectiveness to use in quiescent tissues, and may not provide lifelong expression. In contrast, integrating vectors enhance the risk of insertional mutagenesis. In an attempt to overcome both of these limitations, we created new rAAV-rDNA vectors, with an expression cassette flanked by ribosomal DNA (rDNA) sequences capable of homologous recombination into genomic rDNA. We show that after in vivo delivery the rAAV-rDNA vectors integrated into the genomic rDNA locus 8-13 times more frequently than control vectors, providing an estimate that 23-39% of the integrations were specific to the rDNA locus. Moreover, a rAAV-rDNA vector containing a human factor IX (hFIX) expression cassette resulted in sustained therapeutic levels of serum hFIX even after repeated manipulations to induce liver regeneration. Because of the relative safety of integration in the rDNA locus, these vectors expand the usage of rAAV for therapeutics requiring long-term gene transfer into dividing cells.

Unfractionated heparin dosing in young infants: clinical outcomes in a cohort monitored with anti‐factor Xa levels

Unfractionated heparin (UFH) is a widely used anticoagulant. Current American College of Chest Physicians guidelines for infants extrapolated from adults recommend 28 U kg(-1) h(1) of UFH to achieve an anti-factor Xa level of 0.35-0.7 IU mL(-1). To assess the profile of anti-FXa-based UFH dosing guidelines in infants. We included all infants aged < 6 months treated with per-protocol intravenous UFH at the Hospital for Sick Children, Toronto, over a 3.5-year period. Of 100 infants, 11% achieved sustained therapeutic anti-FXa levels with current dose recommendations. Only 15% achieved target anti-FXa levels within 24 h with per-protocol dose escalations. Seventeen per cent of patients never achieved therapeutic anti-FXa levels, despite up to 60 days of therapy and triple the recommended dose. The median dose needed to achieve therapeutic anti-FXa levels in the remaining 83 infants was 33 U kg(-1) h(-1) (interquartile range, 30-36). Two in three infants had decreased thrombus size at completion of therapy and no thrombus progression/recurrence, and 11/100 infants suffered major bleeding. Without exclusion of extracorporeal membrane oxygenation patients, an activated partial thromboplastin time (APTT) of > 180 s was detected as a risk factor for major bleeding. UFH monitoring is challenging in infants. Despite their delay in reaching therapeutic anti-FXa levels, infants monitored with the adult-based anti-FXa range have a high thrombus resolution rate, no thrombus progression, but a relatively high bleeding rate. Extreme APTT elevation may contribute to this bleeding risk, particularly in critically ill patients. Current UFH guidelines for young infants may still be inadequate, and laboratory methods with age-appropriate ranges may be required to further improve clinical outcomes within this population.

A Multi‐Institutional Observational Study of Testosterone Levels after Testosterone Pellet (Testopel®) Insertion

Implantable testosterone pellets were approved by the Food and Drug Administration in 1972 for the treatment of testosterone deficiency syndrome (TDS). Clinical use of this testosterone delivery modality has been limited until its recent reintroduction (Testopel(®) , Slate Pharmaceuticals, Durham, NC, USA). Six academic institutions collaborated and combined their databases to more fully characterize serum testosterone levels after the pellet implantations. To assess the time-dependent serum testosterone levels after subcutaneous testosterone pellets in clinical practice for the treatment of TDS. Data were retrospectively pooled and analyzed from data in six academic institutions. Variables included patient age, total testosterone concentrations before and after implantation, the number of testosterone pellets implanted, and the time from implantation to measurement of serum testosterone concentrations. Three hundred eighty men undergoing 702 insertions were included for analysis using JMP (version 4.0.4; SAS Institute, Cary, NC, USA). Main outcome measures were postimplantation total testosterone levels and investigator-reported adverse events. Testosterone levels as a function of the number of pellets implanted and time from implantation were assessed. Implantation of six to ≥10 testosterone pellets (450 to ≥750 mg) increased total testosterone into the therapeutic range at 1 month postimplantation and sustained therapeutic levels (>300) for 4-6 months. Higher pellet numbers (10-12 pellets) were associated with higher, more consistent, and longer maintenance of testosterone levels within the therapeutic range. Four extrusions and three hematomas were reported early in our experience; other investigator-reported adverse events were generally mild to moderate in nature and transient in duration. No subjects required analgesics. Testosterone pellets (Testopel(®) , Slate Pharmaceuticals) provide sustained levels of testosterone for at least 4 months and up to 6 months in men with TDS. Implantation of ≥8 pellets achieved optimal results with respect to peak mean testosterone level and duration of effect. Testosterone pellets were generally well tolerated.

IPX066: a novel carbidopa–levodopa extended-release formulation

Levodopa (LD) remains the most effective medication to treat Parkinson’s disease (PD). However, most patients develop motor fluctuations and dyskinesias with long-term LD use. It is thought that these response complications are due, at least in part, to LD’s short half-life. Thus, there is great interest in long-acting LD preparations that might be able to provide robust antiparkinsonian benefit through the day and potentially avoid the development of motor fluctuations and dyskinesias. IPX066 is an investigational extended-release carbidopa–levodopa (CD–LD) formulation. It is designed to achieve rapid absorption and onset of clinical benefit, similar to CD–LD immediate release, and to provide more sustained therapeutic LD levels and longer duration of clinical benefit. In Phase III clinical trials, IPX066 was demonstrated to be efficacious in early PD compared with placebo, and in moderate-to-advanced PD, it provided more sustained clinical benefit with fewer dose administrations than CD–LD immediate release, as reported in published abstracts.

Recent Advances and Future Perspectives in Lentiviral Gene Therapy for Hemophilia A and B

Hemophilia A and B are rare incurable hereditary diseases due to deficiencies in clotting factor VIII (FVIII) and factor IX (FIX), respectively. These genetic defects result in potentially life-threatening, uncontrolled bleeding episodes. Current treatment by protein substitution therapy does not constitute a cure making gene therapy an attractive alternative. Lentiviral vectors (LVs) have many distinctive features that make them especially well suited for FVIII or FIX gene delivery. This includes the lack of vector-specific pre-existing immunity, their ability to permanently transduce both dividing and non-dividing cells and their capacity to readily accommodate FIX and FVIII expression cassettes, consistent with their packaging capacity of 10 kb. LVs have been used to achieve sustained therapeutic clotting factor expression levels and hemostatic correction in preclinical hemophilic mouse models. The liver has been the target organ of choice for direct in vivo LV transduction of FVIII or FIX genes, resulting in sustained therapeutic effects. Nevertheless, the potential development of neutralizing antibodies to the clotting factors following ex vivo or in vivo gene therapy with LVs can preclude long-term phenotypic correction. These risks can be minimized by preventing ectopic expression in antigen-presenting cells. LVs are well suited to deliver the clotting factor genes into hematopoietic stem/progenitor cells, allowing for stable FVIII or FIX expression upon hematopoietic reconstitution. In addition, therapeutic FVIII and FIX expression levels have been achieved in vivo after transplantation of lentivirally transduced endothelial and mesenchymal stem/progenitor cells. Current challenges relate primarily to the translation of these findings to larger preclinical animal models and ultimately to patients suffering from hemophilia.

Transdermal delivery of alprazolam from a monolithic patch: formulation based on in vitro characterization

Alprazolam, a benzodiazepine widely used for the treatment of psychiatric disorders, has been aimed to be formulated in a transdermal delivery system (TDS) prototype. A series of TDS prototypes dosed in all cases at 0.35 mg·cm−2 of alprazolam were prepared as a monolithic drug in adhesive matrix using acrylic pressure-sensitive adhesives (PSA) of acrylate vinyl acetate (Duro-tack®). The effects of several permeation enhancers as azone, transcutol, propylene glycol, dodecyl alcohol, decyl alcohol, diethanolamine, N-methyl pyrrolidone and lauric acid were studied. Prototypes have been characterized based on adhesion parameters (peel adhesion and shear adhesion), in vitro human skin permeation and in vitro drug release according to European Pharmacopoeia for the selected prototype. Best results show that a combination of permeation enhancers from different chemical groups is able to provide almost a 33 fold increase in the transdermal alprazolam flux of an aqueous saturated dispersion (from 0.054 ± 0.019 to 1.76 ± 0.21 μg h.cm−2). Based on these in vitro flux data, a predictive simulation of the achievable plasmatic levels was performed assuming a constant systemic infusion of drug. In summary, it is possible to obtain a prototype of a TDS of alprazolam with adequate adhesive properties (peel adhesion and shear adhesion) and able to predict sustained therapeutic plasmatic levels.

Hemophilia Gene Therapy

Abstract SCI-48 Over the last decade, five clinical studies on gene therapy for hemophilia A and B using viral and nonviral vectors for liver-restricted or ectopic expression of clotting factor demonstrated safety with no inhibitor formation. Although efficacy in these early phase trials was not achieved because of sustained levels of clotting factor below 1%, these studies form the basis for the second generation of clinical trials. To date, two studies on adeno-associated viral (AAV) vector encoding a FIX transgene for liver-restricted expression are ongoing. In one study using a modified AAV genome pseudotyped with serotype 8, emerging data are encouraging and sustained therapeutic levels of FIX have been obtained in a dose-dependent manner. Novel approaches for hemophilia have been explored targeting hematopoietic stem cells (HSC) using lentiviral vectors for expressing FVIII or FIX genes. Transgene expression under the control of either a non-lineage specific promoter or a platelet-specific promoter showed biological activity and improvement of the disease phenotype. The platelet-restricted approaches did not increase circulating plasma clotting factor levels, but they resulted in enrichment of the factor at the injury site upon platelet activation. An advantage of targeting FVIII expression and storage in platelets is the protection of FVIII from neutralizing antibodies (inhibitors). In this model, platelet-FVIII provided superior hemostasis than elevated plasma FVIII levels upon hemostatic challenges in the microcirculation and macrocirculation. Recently, platelet-restricted expression of human FVIII gene using a lentiviral vector for ex vivo transduction of canine HSC resulted in improvement of the disease phenotype in severe hemophilia A dogs without unwanted immune responses to the transgene. Additional strategies to optimize gene- and/or cell-based approaches have also focused on use of clotting factors with enhanced biological activities will be discussed. Together with the generation of novel vectors, further enhancement of both the efficacy the safety of these approaches is envisioned. Disclosures: Arruda: Pfizer: Research Funding.

Assessing Response and Loss of Response to Biological Therapies in IBD

The advent of biological therapies for inflammatory bowel disease (IBD) began in 1998 with the approval of infliximab for the treatment of refractory (to conventional agents) Crohn's disease (CD). Since then, the indications for anti-tumor necrosis factor-α (anti-TNFα) therapy have increased to include induction and maintenance of clinical responses and remissions for luminal and fistulizing CD, the treatment of children with CD, and the treatment of adults with ulcerative colitis. Additional utilities of biological therapies have included demonstrable mucosal healing, improvement in quality of life, reduction in surgeries and hospitalizations, and the treatment of extraintestinal manifestations of IBD including central and peripheral arthritis and pyoderma gangrenosum. Natalizumab has also been approved for the treatment of refractory Crohn's in patients who have failed conventional agents and anti-TNFα therapies. Unfortunately, despite the overall effectiveness of biological agents in a spectrum of indications for IBD, a significant proportion of patients do not respond or lose response over time. In this review, we intend to appraise the latest evolution in treatment strategies in IBD and to suggest an evidence-based approach and risk stratification while coping with cases of non-responders or loss of response to biological therapies. We conducted a literature search of English publications listed in the electronic databases of MEDLINE (source PUBMED) and constructed an analytical review based on definitions of response and loss of response, considering potential responsible mechanisms, clinical assessment tools, and finally recommending a practical approach for its prevention and management. Favorable clinical outcome appears to be the consequence of sustained therapeutic drug levels, and the current literature supports a practice of dose adjustments. When immunogenicity develops to a single biological agent, response can be regained by introduction of an alternative biological agent of the same or different class. Efficacy is reduced with second-line agents either within or across classes compared with naive patients. In the absence of direct measurement of drug levels and anti-drug antibodies, clinical judgment is necessary to assess the mechanisms of loss of response, and more empiric decision making may be necessary to determine the choice of second-line biological agents. Optimal treatment strategies are still controversial. It is essential to recognize the spectrum of mechanisms affecting response and loss of response to form a logical and efficient management algorithm, and, perhaps, it is time to incorporate the measurement of trough levels and anti-drug antibodies in the strategy of such an assessment. Prospective controlled trials are direly needed to investigate the optimal tailored management in individual patients who lose response.

Treatment of Yellow Fever Virus with an Adenovirus-Vectored Interferon, DEF201, in a Hamster Model

Interferon (IFN) is an innate immune response protein that is involved in the antiviral response during viral infection. Treatment of acute viral infections with exogenous interferon may be effective but is generally not feasible for clinical use due to many factors, including cost, stability, and availability. To overcome these limitations, an adenovirus type 5-vectored consensus alpha IFN, termed DEF201, was constructed as a potential way to deliver sustained therapeutic levels of systemic IFN. To demonstrate the efficacy of DEF201 against acute flaviviral disease, various concentrations of the construct were administered as a single intranasal dose prior to virus infection, which resulted in a dose-responsive, protective effect in a hamster model of yellow fever virus (YFV) disease. A DEF201 dose of 5×10(7) PFU/animal administered intranasally just prior to YFV challenge protected 100% of the animals, while a 10-fold lower DEF201 dose exhibited lower, although significant, levels of protection. Virus titers in the liver and serum and levels of serum alanine aminotransferase were all significantly reduced as a result of DEF201 administration at all doses tested. No toxicity, as indicated by weight loss or gross morbidity, was observed in non-YFV-infected animals treated with DEF201. Protection of YFV-infected animals was observed when DEF201 was delivered as early as 7 days prior to virus challenge and as late as 2 days after virus challenge, demonstrating effective prophylaxis and therapy in a hamster model of disease. Overall, it appears that DEF201 is effective in the treatment of YFV in a hamster model.

Drug Delivery to the Posterior Segment of the Eye

Drug delivery into the posterior segment of the eye is complicated by the presence of the blood-ocular barrier. Strategies for delivering drugs to the posterior segment include systemic administration, modification of the blood-eye barrier, and local drug delivery. Recently, new topical treatments have emerged for the treatment of posterior eye disease. Iontophoretic, juxtascleral, and intravitreal routes can be used to achieve therapeutic levels in the posterior segment. Extended-release intravitreal drug delivery systems can achieve sustained therapeutic levels with the goal of providing a prolonged clinical benefit.

Rescue of a Dystrophin-like Protein by Exon Skipping In Vivo Restores GABAA-receptor Clustering in the Hippocampus of the mdx Mouse

Dystrophin, the cytoskeletal protein whose defect is responsible for Duchenne muscular dystrophy (DMD), is normally expressed in both muscles and brain. Genetic loss of brain dystrophin in the mdx mouse model of DMD reduces the capacity for type A gamma-aminobutyric acid (GABA(A))-receptor clustering in central inhibitory synapses, which is thought to be a main molecular defect leading to brain and cognitive alterations in this syndrome. U7 small nuclear RNAs modified to encode antisense sequences and expressed from recombinant adeno-associated viral (rAAV) vectors have proven efficient after intramuscular injection to induce skipping of the mutated exon 23 and rescue expression of a functional dystrophin-like product in muscle tissues of mdx mice in vivo. Here, we report that intrahippocampal injection of a single dose of rAAV2/1-U7 can rescue substantial levels of brain dystrophin expression (15-25%) in mdx mice for months. This is sufficient to completely restore GABA(A)-receptor clustering in pyramidal and dendritic layers of CA1 hippocampus, suggesting exon-skipping strategies offer the prospect to investigate and correct both brain and muscle alterations in DMD. This provides new evidence that in the adult brain dystrophin is critical for the control of GABA(A)-receptor clustering, which may have an important role in activity-dependent synaptic plasticity in hippocampal circuits.

Safety of AAV Factor IX Peripheral Transvenular Gene Delivery to Muscle in Hemophilia B Dogs

Muscle represents an attractive target tissue for adeno-associated virus (AAV) vector–mediated gene transfer for hemophilia B (HB). Experience with direct intramuscular (i.m.) administration of AAV vectors in humans showed that the approach is safe but fails to achieve therapeutic efficacy. Here, we present a careful evaluation of the safety profile (vector, transgene, and administration procedure) of peripheral transvenular administration of AAV-canine factor IX (cFIX) vectors to the muscle of HB dogs. Vector administration resulted in sustained therapeutic levels of cFIX expression. Although all animals developed a robust antibody response to the AAV capsid, no T-cell responses to the capsid antigen were detected by interferon (IFN)-γ enzyme-linked immunosorbent spot (ELISpot). Interleukin (IL)-10 ELISpot screening of lymphocytes showed reactivity to cFIX-derived peptides, and restimulation of T cells in vitro in the presence of the identified cFIX epitopes resulted in the expansion of CD4+FoxP3+IL-10+ T-cells. Vector administration was not associated with systemic inflammation, and vector spread to nontarget tissues was minimal. At the local level, limited levels of cell infiltrates were detected when the vector was administered intravascularly. In summary, this study in a large animal model of HB demonstrates that therapeutic levels of gene transfer can be safely achieved using a novel route of intravascular gene transfer to muscle.

Aerosol and nasal delivery of vaccines and antiviral drugs against seasonal and pandemic influenza

Influenza is primarily a respiratory tract infection involving the exacerbation and inflammation of the respiratory tract, which can progress to life-threatening pneumonia, hypercytokinemia, edema, acute lung injury, respiratory failure and death. Viral mutations and drug resistance are the leading challenges in influenza prevention and treatment. Aerosol inhalation provides rapid availability and sustained therapeutic levels of antiviral drugs in the respiratory tract, without causing a systemic burden to unaffected tissues and organs. Furthermore, aerosol delivery enhances the bioavailability of antiviral drugs with poor oral adsorption. Nasal spray delivery of vaccines provides a safe and needle-free means of vaccination, and contains live-attenuated virus that induces mucosal immunity and provides long-lasting immunity relative to injectable inactivated vaccines. Since influenza is a disease with respiratory clinical manifestations, specific delivery of antiviral drugs or vaccines to the respiratory tract may represent a safe and effective approach to combat influenza.

Pharmacokinetics of intramuscular microparticle depot of valdecoxib in an experimental model

Aim: We did a prospective study to investigate pharmacokinetics of a single intramuscularly (i.m.) administered Valdecoxib (VC) polymeric microparticles in New Zealand white rabbits. Method: Poly[lac(glc-leu)] microparticles encapsulating a potent cyclooxygenase-2- selective inhibitor, VC, were prepared by emulsion and solvent evaporation technique and administered i.m. to rabbits for pharmacokinetic study. Results: A single i.m. dose of drug-loaded poly[lac(glc-leu)] microparticles resulted in sustained therapeutic drug levels in the plasma for 49 days. The relative bioavailability was increased severalfold as compared with unencapsulated drug. Conclusions: Injectable poly[lac(glc-leu)] microparticles hold promise for increasing drug bioavailability and reducing dosing frequency for better management of rheumatoid arthritis.

Bioavailability and In-vivo Transdermal Delivery of Haloperidol

Background: Sustained blood level with effective therapeutic blood level inpsychotic patients in the range of usual therapeutic dose is favorable.Objectives: To investigate where this sustained and effective therapeutic blood level and improve in bioavailability could be achieved by usinghaloperidol/transdermal gel formulation.Materials and Methods: In-vivo transdermal delivery of haloperidol wasstudied in rabbits comparing transdermal gel formulation containing 1, 8-cineole as penetration enhancer and oral tablet. Concentrations of haloperidol in plasma were measured by reverse phase HPLC. The pharmacokinetic parameters generated from this study were evaluatedstatistically using one-way analysis of variance (ANOVA).Result: The results showed that transdermal gel formulation increased rate and extent of absorption and improve bioavailability of haloperidol. The plasma concentrations of haloperidol were declined in biexponential fashion where the area under the curves and absorption rate Cmax/AUC elimination rate constant Kel, Tmax, mean residence time (MRT), mean absorption time (MAT), and total clearance (CLtotal) were significantly different p < 0.05, but volume of distribution (Vd) did not differ significantly p >0.05.The absolute bioavailability from the oral tablet, and the transdermal formulation was 38% and 57% respectively and highly significant P < 0.01.Conclusion: This study suggest that it is possible to achieve significant sustained therapeutic blood levels for longer time and also suggest that further human investigations of the transdermal dosage are warranted.Key words: Haloperidol/Transdermal gel formulation, Oral tablet, Rabbits, Bioavailability,Pharmacokinetic.

Correction of ADAMTS13 Deficiency by In Utero Gene Transfer of Lentiviral Vector encoding ADAMTS13 Genes

Deficiency of A Disintegrin And Metalloprotease with ThromboSpondin (ADAMTS13) results in thrombotic thrombocytopenic purpura (TTP). Plasma infusion or exchange is the only effective treatment to date. We show in this study that an administration of a self-inactivating lentiviral vector encoding human full-length ADAMTS13 and a variant truncated after the spacer domain (MDTCS) in mice by in utero injection at embryonic days 8 and 14 resulted in detectable plasma proteolytic activity (approximately 5-70%), which persisted for the length of the study (up to 24 weeks). Intravascular injection via a vitelline vein at E14 was associated with significantly lower rate of fetal loss than intra-amniotic injection, suggesting that the administration of vector at E14 may be a preferred gestational age for vector delivery. The mice expressing ADAMTS13 and MDTCS exhibited reduced sizes of von Willebrand factor (vWF) compared to the Adamts13(-/-) mice expressing enhanced green fluorescent protein (eGFP). Moreover, the mice expressing both ADAMTS13 and MDTCS showed a significant prolongation of ferric chloride-induced carotid arterial occlusion time as compared to the Adamts13(-/-) expressing eGFP. The data demonstrate the successful correction of the prothrombotic phenotypes in Adamts13(-/-) mice by a single in utero injection of lentiviral vectors encoding human ADAMTS13 genes, providing the basis for developing a gene therapy for hereditary TTP in humans.

AAV2/1-TNFR:Fc gene delivery prevents periodontal disease progression

SUMMARYPeriodontal disease is a chronic inflammatory condition induced by tooth-associated microbial biofilms that induce a host immune response. Therapeutic control of progressive tissue destruction in high-risk patients is a significant challenge in therapy. Soluble protein delivery of antagonists to tumor necrosis factor alpha (TNF-α) inhibits alveolar bone resorption due to periodontitis. However, protein therapy raises several concerns, such as recurrence of disease activity after treatment cessation and repeated dosing regimens. In this study, we used pseudotyped adeno-associated virus vector based on serotype 1 (AAV2/1) to deliver the TNF receptor-immunoglobulin Fc (TNFR:Fc) fusion gene to rats subjected to experimental Porphyromonas gingivalis (Pg)-lipopolysaccharide (LPS)-mediated bone loss. Animals received Pg-LPS delivered to the gingivae thrice weekly for 8 weeks, vehicle alone, Pg-LPS and intramuscular delivery of pseudotyped AAV2/1-TNFR:Fc vector (1×1011 DNase I-resistant particles) or AAV2/1-TNFR:Fc vector delivered to naïve animals. AAV2/1-TNFR:Fc therapy led to sustained therapeutic levels of serum TNFR protein and protected against Pg-LPS-mediated loss of bone volume and density. Furthermore, AAV2/1-TNFR:Fc administration reduced local levels of multiple pro-inflammatory cytokines and osteoclast-like cells at the periodontal lesions. These findings suggest that delivery of AAV2/1-TNFR:Fc may be a viable approach to modulate periodontal disease progression.