BIOCHEMISTRY, BIOMEDICINE & PHARMACEUTICS

Vestronidase alfa, an enzyme replacement therapy, is an approved drug for the treatment of MPS VII. The approval of this drug has set a precedent for future drug development for the regulators and drug developers. First, the pivotal clinical trial was conducted to evaluate the totality of the clinical data for determining the efficacy of the treatment, therefore, no primary clinical endpoint was established. Second, the drug obtains approval positive outcome on the secondary endpoint; changes in the urinary glycosaminoglycan, from placebo control. The glycosaminoglycan is also the pharmacodynamic biomarker that reflected the efficacy of the drug. Third, the novel multi-domain clinical responder index was designed to evaluate the treatment outcomes and included six minutes walk test (6MWT), forced vital capacity (FVC), shoulder range motion, visual acuity, BOT-2 fine, and gross motor activity. While MRDI evaluation per subject suggested the stabilization of clinical condition if no...

Immune response associated adverse events and hypersensitivity reactions are the major safety concerns related to enzyme replacement therapies. The immunogenicity against these therapeutic enzymes depends on structural similarities, manufacturing processes, formulation, and impurities etc. The drug developer has developed strategies to mitigate manufacturing related immunogenicity risk with improved processes such as optimization of the protein sequence, mammalian cell lines to express and purify recombinant human enzymes. Despite these efforts, the immunogenicity and anti-drug antibody generation against these therapeutic proteins are heterogeneous among the populations. In the same dose cohort, one subject may produce higher anti-drug antibodies titer with lesser efficacy. In contrast, another subject may have less or no anti-drug antibodies with no impact on drug efficacy. Identify and characterizing these individual factors would enable a better understanding of individual fact...

Adeno associated virus (AAV) is a naturally occurring single-stranded DNA virus that belongs to the parvovirus family. The commonly used viral vectors for gene therapy are derived from naturally occurring AAVs. These vectors are genetically modified/engineered that do not contain and devoid of genes encoding viral proteins critical for their viral replication. The viral gene is replaced with the transgene of interest is packaged into the AAV viral capsid and administration to humans. The AAV viral vectors enable attachment and entry of transgene into the target cells. Once inside the cell nucleus, the transgene remains in the episomal form and expresses the gene of interest. Although recent evidence has shown that long-term stable expression of these transgenes can be achieved in pre-clinical models and humans, there is inherent immunogenicity risk associated with adeno-associated vectors which include: -Pre-existing antibodies and T cell response against viral vectors -Neutralizing an...

What are Hemophilia disorders ? Hemophilia is the group of bleeding disorders that are caused by a deficiency of proteins (factors) of the blood clotting cascade. Hemophilia A is caused by the deficiency of factor VIII protein and Hemophilia B is caused by a downstream protein factor IX. The deficiency of the factors VIII and IX affect the clotting cascade, resulting in higher and spontaneous bleeding episodes. The severe bleeding disorder leads to spontaneous bleeding in joints and soft tissue resulting in arthropathy; and increased risk of intravascular and intracranial hemorrhage. Why the development of new treatment paradigm is necessary? The standard treatment for hemophilia (A and B type) is the intravenous infusion of an exogenous clotting protein more than once a week to prevent bleeding. In addition, the development of inhibitors decreases the efficacy of the exogenous replacement factor and the severe hemophilia patients do not respond to these therapies.  There...

Inherited Biallelic RPE65 Mutation-Associated Retinal Dystrophy Inherited retinal dystrophies are a group of rare blinding conditions that are associated with progressive visual dysfunction. This rare genetic disorder is classified based on the phenotype, and the mutation in any one of more than 220 different genes are causal for this rare blinding condition. Retinitis pigmentosa is the most common subgroup of inherited retinal dystrophy characterized by reduced ability to perceive light and progressive loss of visual field. RP is genetically heterogeneous, and mutations in any one of over one hundred genes can cause the phenotype. RPE65 gene encodes all-trans-retinyl ester isomerase, an enzyme crucial to the retinoid cycle Autosomal recessive biallelic mutations in this gene lead to the inability to regenerate 11-cis-retinal, via 11-cis-retinol, in the retinal pigment epithelial cells RPE cells. This impairs the ability of RPE cells to respond to light, which disrupts the vis...

Linearity: The alternative approach for detecting non-linearity is to assess the residuals of an estimated regression line and test for whether positive and negative deviations are randomly distributed. It should be considered whether an estimated regression line passes through zero or not. The presence of linearity is a prerequisite for a high degree of trueness. Linearity refers to the relationship between measured and expected values over the analytical measurement range. Linearity may be considered in relation to the actual or relative analyte concentration. In case of relative analyte concentrations, a dilution series of a sample may be studied. The relative analyte concentration method is often used for immunoassays to measure whether the concentration decreases with dilution as expected. Dilution is usually carried out with the appropriate sample matrix. Analytical Range: The analytical range or reportable range is the analyte concentration range over which the measurement i...

The surfactants are chemical substance that is capable of lowering surface tension. The lung surfactants contain a complex mixture of phospholipids, neutral lipids, and specific proteins. The lung surfactants are essential for normal lung function as it reduces surface tension at the air-liquid interface of alveolar spaces.  Phosphatidylcholine is a major component of the surfactant comprising 90% of the lipids. Four specific surfactant proteins SP-A, SP-B, SP-C, SP-D. The synthesis and secretion of functional surfactants are confined to type II cells of the alveolar epithelium. The fundamental pathway for lung surfactant phospholipid synthesis, it's packaging into storage lamellar bodies (LB), secretion into the alveolar lining fluid and recycling back into ATII cells are well known. Bulk surfactant phospholipid synthesized at the ER is transported to LBs by a mechanism that may employ specific carrier proteins and/or traffic through the Golgi.  During the processes of s...