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INTRODUCTION: Prophylactic treatment of hemophilia B with recombinant factor IX (rFIX) molecules with enhanced pharmacokinetics including rIX-FP (albutrepenonacog alfa; Idelvion©) and rFIXFc (eftrenonacog alfa; Alprolix©) have commonly been used in the clinic. In the absence of head-to-head comparative trials, the aim of this study was to estimate the efficacy of rIX-FP versus rFIXFc using matching-adjusted indirect comparisons (MAICs). METHODS: MAIC analyses leveraged individual patient data from the PROLONG-9FP trial and published summary-level data from the B-LONG trial for subjects who received weekly prophylaxis regimens. Individual patient data were used to assign weights and balance subjects from PROLONG-9FP with subjects from B-LONG on baseline disease severity, age, prior FIX regimen, and body mass index (BMI). Six efficacy outcomes were analyzed including annualized bleeding rate (ABR), annualized spontaneous bleeding rate (AsBR), annualized joint bleeding rate (AjBR), and the proportion of subjects without bleeding events (for total, spontaneous, and joint bleeding events). RESULTS: After adjustment for baseline disease severity, age, prior FIX regimen, and BMI, rIX-FP was associated with a statistically significant decrease in AsBR (rate ratio [RR] 0.42; 95% confidence interval [CI] 0.22, 0.82; P = 0.0107), and the proportion of patients without bleeding events (odds ratio [OR] 3.24; 95% CI 1.41, 7.45; P = 0.0057), spontaneous bleeding events (OR 3.47; 95% CI 1.56, 7.73; P = 0.0023), and joint bleeding events (OR 2.41; 95% CI 1.10, 5.26; P = 0.0274) compared with rFIXFc. Prophylactic treatment with rIX-FP was also associated with a numerically lower ABR (RR 0.75; 95% CI 0.32, 1.75; P = 0.5095) and AjBR (RR 0.82; 95% CI 0.37, 1.82; P = 0.6178). CONCLUSION: The MAICs demonstrated that weekly prophylaxis treatment of severe hemophilia B with rIX-FP resulted in favorable efficacy outcomes as compared to rFIXFc. These findings suggest rIX-FP may offer improved clinical benefits over rFIXFc.

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The successful expression and secretion of recombinant proteins in cell factories significantly depend on the correct folding of nascent peptides, primarily achieved through disulfide bond formation. Thus, optimizing cellular protein folding is crucial, especially for proteins with complex spatial structures. In this study, protein disulfide isomerases (PDIs) from various species were introduced into Saccharomyces cerevisiae to facilitate proper disulfide bond formation and enhance recombinant protein secretion. The impacts of these PDIs on recombinant protein production and yeast growth metabolism were evaluated by substituting the endogenous PDI1. Heterologous PDIs cannot fully compensate the endogenous PDI. Furthermore, protein folding mediators, PDI and ER oxidoreductase 1 (Ero1), from different species were used to increase the production of complex human serum albumin (HSA) fusion proteins. The validated folding mediators were then introduced into unfolded protein response (UPR)-optimized strains, resulting in a 7.8-fold increase in amylase-HSA and an 18.2-fold increase in albiglutide compared with the control strain. These findings provide valuable insights for optimizing protein folding and expressing HSA-based drugs.

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Hemophilia B is a bleeding disorder caused by a deficiency of coagulation factor IX (FIX). Treatment with FIX replacement products can increase FIX activity levels to minimize or prevent bleeding events. However, frequent dosing with standard-acting FIX products can create a high treatment burden. Long-acting products have been developed to maintain bleed protection with extended dosing intervals. Recombinant factor IX-albumin fusion protein (rIX-FP) is a long-acting product indicated for the treatment and prophylaxis of bleeding events and perioperative management in adult and pediatric patients. This review outlines data from all previously treated patients in the Prophylaxis and On-Demand Treatment using Longer Half-Life rIX-FP (PROLONG-9FP) clinical trial program and summarizes real-world data evaluating the use of rIX-FP in routine clinical practice. In the PROLONG-9FP program, rIX-FP demonstrated effective hemostasis in all patients at dose regimens of up to 21 days in patients aged ≥ 18 years and up to 14 days in patients aged < 12 years. rIX-FP has a favorable pharmacokinetic profile and an excellent safety and tolerability profile. Extended dosing intervals with rIX-FP led to high levels of adherence and reduced consumption compared with other FIX therapies. Data from real-world practice are encouraging and reflect the results of the clinical trials.

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@#This study is performed to analyze the anti-liver fibrosis effect of the fusion protein of human serum albumin and extracellular domain of transforming growth factor beta type II receptor(eTGFBR2)in vivo to looking for the more stable anti-liver fibrosis drug. The mice model of liver fibrosis was constructed by CCl4 induction and the following groups are included in the study: the control group, CCl4 model group, the positive control group, eTGFBR2 treatment group, HSA-eTGFBR2 treatment group, and HSA group. Hematoxylin eosin staining, serum liver function index detection, and western blot are used to identify the anti-liver fibrosis activities. The results showed that: (1)CCl4 caused liver structure disorder, hepatocellular necrosis, collagen fibers proliferation, and induced liver fibrosis at last; (2)HSA-eTGFBR2 and its monomer drug improved the symptoms of liver fibrosis significantly, as well as reduced the damage of liver cells and collagen deposition, and recovered the liver basic structure to normal. Both of HSA-eTGFBR2 and its monomer drug improved liver function and reduced the expression level of liver fibrosis marker α-SMA and COL I. Moreover, the anti-liver fibrosis effect of the fusion protein is comparable to the monomer drug. In contrast, the albumin had no effect on therapeutic effect; (3)Reducing the injection frequency of HSA-eTGFBR2 achieved the comparable effects to the monomer drug with the normal injection frequency. In summary, the fusion protein HSA-eTGFBR2 has good anti-liver fibrosis effect. In addition, reducing the injection frequency of the fusion protein could also achieve the comparable treatment with the monomer drug, indicating that the fusion protein is stable and has longer half-lives and then a relatively positive application prospect in future.

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Human serum albumin (HSA) fusion protein is a viable and effective approach to target and inhibit essential intracellular pathways. It has previously been shown that an HSA fusion protein containing a p53-reactivating peptide (rHSA-p53i) retains the binding activity to MDM2 and MDMX, resulting in p53 transcription-dependent apoptosis. Here, we demonstrate that rHSA-p53i is able to bind and neutralize anti-apoptotic Bcl-2 family proteins, Bcl-xL and Mcl-1. This interaction displaces pro-apoptotic Bak and subsequently leads to intrinsic apoptosis via mimicking a p53 transcription-independent pathway. Cytotoxicity induced by rHSA-p53i, via p53 transcription dependent and independent apoptotic pathways, is irrespective of the p53 status in MDA-MB-231, HeLa, and SJSA-1 cells possessing either mutant, deficient, or wild-type p53. The therapeutic potential is also confirmed by treating SJSA-1 and MDA-MB-231 xenograft mouse tumors with rHSA-p53i. These data reveal that rHSA-p53i interferes with at least four intracellular targets, making it a viable therapeutic protein for the treatment of a variety of cancers, as well as a carrier to deliver fatty acid-modified chemotherapeutics.

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The neonatal Fc receptor (FcRn) has a pivotal role in albumin and IgG homeostasis. Internalized IgG captured by FcRn under acidic endosomal conditions is recycled to the cell surface where exocytosis and a shift to neutral pH promote extracellular IgG release. Although a similar mechanism is proposed for FcRn-mediated albumin intracellular trafficking and recycling, this pathway is less well defined but is relevant to the development of therapeutics exploiting FcRn to extend the half-life of short-lived plasma proteins. Recently, a long-acting recombinant coagulation factor IX-albumin fusion protein (rIX-FP) has been approved for the management of hemophilia B. Fusion to albumin potentially enables internalized proteins to engage FcRn and escape lysosomal degradation. In this study, we present for the first time a detailed investigation of the FcRn-mediated recycling of albumin and the albumin fusion protein rIX-FP. We demonstrate that following internalization via FcRn at low pH, rIX-FP, like albumin, is detectable within the early endosome and rapidly (within 10-15 min) traffics into the Rab11+ recycling endosomes, from where it is exported from the cell. Similarly, rIX-FP and albumin taken up by fluid-phase endocytosis at physiological pH traffics into the Rab11+ recycling compartment in FcRn-positive cells but into the lysosomal compartment in FcRn-negative cells. As expected, recombinant factor IX (without albumin fusion) and an FcRn interaction-defective albumin variant localized to the lysosomal compartments of both FcRn-expressing and nonexpressing cells. These results indicate that FcRn-mediated recycling via the albumin moiety is a mechanism for the half-life extension of rIX-FP observed in clinical studies.

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Pichia pastoris is generally considered as an expression host for heterologous proteins with the coding gene under control of the alcohol oxidase 1 (AOX1) promoter. The secretion of heterologous proteins in P. pastoris can be potentially affected by many factors. Based on our previous results, the secretion levels of human albumin (HSA) fusion protein IL2-HSA were only around 500 mg/L or less in fermentor cultures, which decreased more than 50% compared with that of HSA (>1 g/L). In this study, we selected five potential secretion helper factors, in which Ero1, Pdi1 and Kar2 were involved in protein folding and Sec1 and Sly1 were involved in vesicle trafficking. We evaluated the possible effects of individual overexpression of these secretion helper factors on the secretion of IL2-HSA in P. pastoris. Constitutive overexpression of the five selected secretion factors did not have an obvious negative effect on cell growth of the IL2-HSA secreting strain. Individual co-overexpression of Ero1, Kar2, Pdi1, Sec1 and Sly1 improved the secretion level of IL2-HSA to ~2.3-, 1.9-, 2.2-, 2.5- and 1.9-fold that in the control strain respectively in shake flasks. We evaluated the changes in mRNA and protein levels of the intracellular IL2-HSA, as well as the secretion helper factor genes in the co-overexpressing strains. Our results indicated that manipulating the expression level of ER resident protein Pdi1, Ero1, Kar2 and SM protein Sec1 and Sly1 could improve the secretion level of IL2-HSA fusion protein in P. pastoris, which provided new candidates for combinatorial engineering in future study. Copyright © 2016 John Wiley & Sons, Ltd.

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Self-reactive antibodies represent a significant force in autoimmune disease induction. In antibody-dependent autoimmune syndromes such as immune thrombocytopenia (ITP), systemic lupus erythematosus (SLE), myasthenia gravis and rheumatoid arthritis (RA), autoantibodies exert their inflammatory effect through FcγRs, a well-established class of cell surface receptors that interact with the Fc domain of IgG. Down-regulating FcγR functionality presents an attractive strategy to treat antibody-dependent autoimmune diseases. Various approaches, including nonspecific blocking of the IgG binding site as well as specific targeting using antagonistic monoclonal antibodies, have been explored to modulate the interaction between the Fc portion of IgG and FcγRs. The exquisite specificity and favorable pharmacokinetics of IgG make monoclonal antibodies a preferred choice. Indeed, the first antagonistic monoclonal antibody against the human FcγRIIIA had shown efficacy in refractory ITP patients; however, the practicality of using anti-FcγRIII antibody as a therapeutic was hindered by its associated adverse events, a phenomenon recapitulated in animal models. In this review, we discuss the role of FcγRs in autoimmune diseases, and focus on a novel monovalent approach to target FcγRs to resolve antibody-mediated autoimmunity.

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