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Immobilized enzymes offer different benefits such as the feasibility to be reused for reproducible bioprocesses. The challenge is to establish the appropriate storage conditions that allow the maintenance of their properties for long periods. In this study, we immobilized a recombinant leucine aminopeptidase (I-rLAP) on a siliceous support synthesized from tetraethyl orthosilicate (TEOS) activated with glutaraldehyde to evaluate its residual activity after storage in 20% v/v ethanol and sodium azide solutions at 4 and 25 °C. The characterization of the support by X-ray diffraction (XRD), diffuse reflectance infrared Fourier transform (DRIFT) and field emission probe microanalyzer (EPMA) was consistent with previous characterization reports of silica gel matrices. Particle size ≤420 μm exhibited a suitable performance that avoided high backpressure into the columns and increased the amount of immobilized enzyme. I-rLAP recovered up to 90% of the applied activity after 64 days of storage at 4 and 25 °C in 20% v/v ethanol. Conversely, no effect was observed when the insoluble enzyme was stored in sodium azide. Activity recovery of I-rLAP after storage in ethanol solution could be related to the formation of disulfide bonds as suggested by free thiol analyses. Reverse phase-ultra performance liquid chromatography (RP-UPLC) and Mass Spectrometry confirmed that the immobilized enzyme maintained its specificity to remove N-terminal methionine from a recombinant hormone. The obtained results indicate that this methodology constitutes an alternative for bioprocesses involving long-term storage of immobilized enzymes. [ABSTRACT FROM PUBLISHER]

Complex pharmaceuticals are in demand of competent analytical methods able to analyze charge heterogeneity as a critical quality attribute (CQA), in compliance with current regulatory expectations. A notorious example is glatiramer acetate (GA), a complex polypeptide mixture useful for the treatment of relapsing-remitting multiple sclerosis. This pharmaceutical challenges the current state of analytical technology in terms of the capacity to study their constituent species. Thus, a strong cation exchange methodology was designed under the lifecycle approach to support the establishment of GA identity, trough the evaluation of its chromatographic profile, which acts as a charge heterogeneity fingerprint. In this regard, a maximum relative margin of error of 5% for relative retention time and symmetry factor were proposed for the analytical target profile. The methodology met the proposed requirements after precision and specificity tests results, the former comprised of sensitivity and selectivity. Subsequently, method validation was conducted and showed that the method is able to differentiate between intact GA and heterogeneity profiles coming from stressed, fractioned or process-modified samples. In summary, these results provide evidence that the method is adequate to assess charge heterogeneity as a CQA of this complex pharmaceutical. [ABSTRACT FROM AUTHOR]

Background: Developing countries have an estimate of ten times more approved biosimilars than developed countries. This disparity demands the need of an objective regulation that incorporates health policies according to the technological and economical capabilities of each country. One of the challenges lies on the establishment of comparability principles based on a physicochemical and biological characterization that should determine the extent of additional non-clinical and clinical studies. This is particularly relevant for licensed biosimilars in developing countries, which have an extensive clinical experience since their approval as generics, in some cases more than a decade. To exemplify the current status of biosimilars in Mexico, a characterization exercise was conducted on licensed filgrastim biosimilars using pharmacopeial and extended characterization methodologies. Results: Most of the evaluated products complied with the pharmacopeial criteria and showed comparability in their Critical Quality Attributes (CQAs) towards the reference product. These results were expected in accordance with their equivalent performance during their licensing as generics. Accordingly, a rational approval and registration renewal scheme for biosimilars is proposed, that considers the proper identification of CQAs and its thoroughly evaluation using selected techniques. Conclusions: This approach provides support to diminish uncertainty of exhibiting different pharmacological profiles and narrows or even avoids the necessity of comparative clinical studies. Ultimately, this proposal is intended to improve the accessibility to high quality biosimilars in Latin America and other developing countries. [ABSTRACT FROM AUTHOR]

This work describes a strategy to optimize a downstream processing of a recombinant human growth hormone (rhGH) by incorporating a quality by design approach toward meeting higher quality specifications. The optimized process minimized the presence of impurities and degradation by-products during manufacturing by the establishment of in-process controls. Capillary zone electrophoresis, reverse phase, and size-exclusion chromatographies were used as analytical techniques to establish new critical process parameters for the solubilization, capture, and intermediate purification steps aiming to maintain rhGH quality by complying with pharmacopeial specifications. The results indicated that the implemented improvements in the process allowed the optimization of the specific recovery and purification of rhGH without compromising its quality. In addition, this optimization facilitated the stringent removal of the remaining impurities in further polishing stages, as demonstrated by the analysis of the obtained active pharmaceutical ingredient. [ABSTRACT FROM AUTHOR]

Etanercept is a recombinant fusion protein approved for the treatment of TNF-α mediated diseases such as rheumatoid arthritis (RA), psoriasis, psoriatic arthritis, and ankylosing spondylitis. Herein, we present an evaluation of the physicochemical and biological properties of a biosimilar etanercept and its reference product followed by a clinical study in patients diagnosed with RA intended to demonstrate comparability of their immunomodulatory activity. Identity analyses showed a total correspondence of the primary and higher-order structure between the two products. In regard to intrinsic heterogeneity, both products showed to be highly heterogenous; however the biosimilar etanercept exhibited similar charge and glycan heterogeneity intervals compared to the reference product. Apoptosis inhibition assay also showed that, despite the high degree of heterogeneity exhibited by both products, no significant differences exist in their in vitro activity. Finally, the clinical assessment conducted in RA-diagnosed patients did not show significant differences in the evaluated pharmacodynamic markers of both products. Collectively, the results from the comparability exercise provide convincing evidence that the evaluated biosimilar etanercept can be considered an effective alternative for the treatment of RA. [ABSTRACT FROM AUTHOR]

Comparability between a biosimilar and its reference product requires the evaluation of critical quality attributes that may impact on its pharmacological response. Herein we present a physicochemical characterization of a biosimilar trastuzumab focused on the attributes related to the pharmacokinetic response. Capillary isoelectrofocusing (cIEF) and cation exchange chromatography (CEX) were used to evaluate charge heterogeneity; glycosylation profiles were assessed through hydrophilic interaction liquid chromatography (HILIC); aggregates content was evaluated through size exclusion chromatography (SEC) while binding affinity to FcRn was evaluated using isothermal titration calorimetry (ITC). The biosimilar trastuzumab and its reference product exhibited a high degree of similarity for the evaluated attributes. In regard to the pharmacokinetic parameters, randomized, double blind, and two-arm parallel and prospective study was employed after the administration of a single intravenous dose in healthy volunteers. No significant differences were found between the pharmacokinetic profiles of both products. Our results confirm that similarity of the critical quality attributes between a biosimilar product, obtained from a different manufacturing process, and the reference product resulted in comparable pharmacokinetic profiles, diminishing the uncertainty related to the biosimilar’s safety and efficacy. [ABSTRACT FROM AUTHOR]

Analysis of the physical properties of biotherapeutic proteins is crucial throughout all the stages of their lifecycle. Herein, we used size-exclusion ultra high performance liquid chromatography coupled to multiangle light scattering and refractive index detection systems to determine the molar mass, mass-average molar mass, molar-mass dispersity and hydrodynamic radius of two monoclonal antibodies (rituximab and trastuzumab), a fusion protein (etanercept), and a synthetic copolymer (glatiramer acetate) employed as models. A customized instrument configuration was set to diminish band-broadening effects and enhance sensitivity throughout detectors. The customized configuration showed a performance improvement with respect to the high-performance liquid chromatography standard configuration, as observed by a 3 h column conditioning and a higher resolution analysis in 20 min. Analysis of the two monoclonal antibodies showed averaged values of 148.0 kDa for mass-average molar mass and 5.4 nm for hydrodynamic radius, whereas for etanercept these values were 124.2 kDa and 6.9 nm, respectively. Molar-mass dispersity was 1.000 on average for these proteins. Regarding glatiramer acetate, a molar mass range from 3 to 45 kDa and a molar-mass dispersity of 1.304 were consistent with its intrinsic peptide diversity, and its mass-average molar mass was 10.4 kDa. Overall, this method demonstrated an accurate determination of molar mass, overcoming the difficulties of size-exclusion chromatography. [ABSTRACT FROM AUTHOR]

According to the World Health Organization, the incidence of malignant neoplasms and endocrine, blood, and immune disorders will increase in the upcoming decades along with the demand of affordable treatments. In response to this need, the development of biosimilar drugs is increasing worldwide. The approval of biosimilars relies on the compliance with international guidelines, starting with the demonstration of similarity in their physicochemical and functional properties against the reference product. Subsequent clinical studies are performed to demonstrate similar pharmacological behavior and to diminish the uncertainty related to their safety and efficacy. Herein we present a comparability exercise between a biosimilar trastuzumab and its reference product, by using a hierarchical strategy with an orthogonal approach, to assess the physicochemical and biological attributes with potential impact on its pharmacokinetics, pharmacodynamics, and immunogenicity. Our results showed that the high degree of similarity in the physicochemical attributes of the biosimilar trastuzumab with respect to the reference product resulted in comparable biological activity, demonstrating that a controlled process is able to provide consistently the expected product. These results also constitute the basis for the design of subsequent delimited pharmacological studies, as they diminish the uncertainty of exhibiting different profiles. [ABSTRACT FROM AUTHOR]

Analysis of the physical properties of biotherapeutic proteins is crucial throughout all the stages of their lifecycle. Herein, we used size-exclusion ultra high performance liquid chromatography coupled to multiangle light scattering and refractive index detection systems to determine the molar mass, mass-average molar mass, molar-mass dispersity and hydrodynamic radius of two monoclonal antibodies (rituximab and trastuzumab), a fusion protein (etanercept), and a synthetic copolymer (glatiramer acetate) employed as models. A customized instrument configuration was set to diminish band-broadening effects and enhance sensitivity throughout detectors. The customized configuration showed a performance improvement with respect to the high-performance liquid chromatography standard configuration, as observed by a 3 h column conditioning and a higher resolution analysis in 20 min. Analysis of the twomonoclonal antibodies showed averaged values of 148.0 kDa for mass-averagemolar mass and 5.4nmfor hydrodynamic radius, whereas for etanercept these values were 124.2 kDa and 6.9 nm, respectively. Molar-mass dispersity was 1.000 on average for these proteins. Regarding glatiramer acetate, a molar mass range from 3 to 45 kDa and a molar-mass dispersity of 1.304 were consistent with its intrinsic peptide diversity, and its mass-average molar mass was 10.4 kDa. Overall, this method demonstrated an accurate determination ofmolar mass, overcoming the difficulties of size-exclusion chromatography. [ABSTRACT FROM AUTHOR]

Rituximab is a chimeric monoclonal antibody employed for the treatment of CD20-positive B-cell non-Hodgkin’s lymphoma, chronic lymphocytic leukemia, rheumatoid arthritis, granulomatosis with polyangiitis and microscopic polyangiitis. It binds specifically to the CD20 antigen expressed on pre-B and consequently on mature B-lymphocytes of both normal and malignant cells, inhibiting their proliferation through apoptosis, CDC, and ADCC mechanisms. The immunomodulatory activity of rituximab is closely related to critical quality attributes that characterize its chemical composition and spatial configuration, which determine the recognition of CD20 and the binding to receptors or factors involved in its effector functions, while regulating the potential immunogenic response. Herein, we present a physicochemical and biological characterization followed by a pharmacodynamics and immunogenicity study to demonstrate comparability between two products containing rituximab. The physicochemical and biological characterization revealed that both products fit within the same response intervals exhibiting the same degree of variability. With regard to clinical response, both products depleted CD20+ B-cells until posttreatment recovery and no meaningful differences were found in their pharmacodynamic profiles. The evaluation of anti-chimeric antibodies did not show differential immunogenicity among products. Overall, these data confirm that similarity of critical quality attributes results in a comparable immunomodulatory activity. [ABSTRACT FROM AUTHOR]

The function of proteins, such as the catalytic enzyme activity, depends on the interaction of their active sites with their specific substrates and the environment conditions that affect the stability of those sites. This study presents a structure-to-function characterization of the folding process of a recombinant 6×-His tag leucine aminopeptidase ( r LAP) based on a platform of analytical techniques. The results demonstrated an increase up to 31 U/mg in the activity of the enzyme after folding as revealed by circular dichroism, intrinsic fluorescence, differential scanning calorimetry, and free thiol analysis. Collectively, these techniques revealed a larger number of covalent and non-covalent bonds within the protein seen as an increase in the chemical and thermal stability, while exhibited a lower level of non-bonded cysteines after the protein was folded. Mass spectrometry analysis showed the maintenance of the distribution of the enzyme isoforms related to N-terminal histidine residues after folding, which confirmed that the enzymatic activity of r LAP depends on its three-dimensional structure rather than N-terminal self-processing activity. In summary, the studied attributes allow a better understanding of the structure-to-function relationship of r LAP, that permit a more proficient manufacturing of the enzyme that would improve the bioprocesses in which is employed. [ABSTRACT FROM AUTHOR]

Leucine aminopeptidase from Vibrio proteolyticus is a broad specificity N-terminal aminopeptidase that is widely used in pharmaceutical processes where the removal of N-terminal residues in recombinant proteins is required. We previously reported the expression of a heterologous construction of the mature protein fused to a 6-histidine tag that presents a reasonable refolding rate for its use at industrial level. Here, we investigate this recombinant leucine aminopeptidase (rLAP) to explain the gain of activity observed when incubated at 37°C after its production. Unfolding transitions of rLAP as a function of urea concentration were monitored by circular dichroism (CD) and fluorescence (FL) spectroscopy exhibiting single transitions by both techniques. Free energy change for unfolding measured by CD and FL spectroscopy are 2.8±0.4 and 3.7±0.4kcalmol−1, respectively. Thermal stability conformation of rLAP is 2.6±0.1 and 6.1kcalmol−1 for CD and Nano-Differential Scanning Calorimetry (Nano-DSC), respectively. Enzyme activity was assessed with l-leucine-p-nitroanilide (L-pNA) as substrate. The catalytic efficiency was 3.87±0.10min−1 μM−1 at 37°C and pH 8.0. Kinetic and conformation studies show differences between the enzyme native and rLAP; however rLAP is selective and specific to remove N-terminal groups from amino acids. [ABSTRACT FROM AUTHOR]

Protein structure depends on weak interactions and covalent bonds, like disulfide bridges, established according to the environmental conditions. Here, we present the validation of two spectroscopic methodologies for the measurement of free and unoxidized thiols, as an attribute of structural integrity, using 5,5'-dithionitrobenzoic acid (DTNB) and DyLight Maleimide (DLM) as derivatizing agents. These methods were used to compare Rituximab and Etanercept products from different manufacturers. Physicochemical comparability was demonstrated for Rituximab products as DTNB showed no statistical differences under native, denaturing, and denaturing-reducing conditions, with Student's t-test P values of 0.6233, 0.4022, and 0.1475, respectively. While for Etanercept products no statistical differences were observed under native (P = 0.0758) and denaturing conditions (P = 0.2450), denaturing-reducing conditions revealed cysteine contents of 98% and 101%, towards the theoretical value of 58, for the evaluated products from different Etanercept manufacturers. DLM supported equality between Rituximab products under native (P = 0.7499) and denaturing conditions (P = 0.8027), but showed statistical differences among Etanercept products under native conditions (P < 0.001). DLM suggested that Infinitam has fewer exposed thiols than Enbrel, although DTNB method, circular dichroism (CD), fluorescence (TCSPC), and activity (TNFα neutralization) showed no differences. Overall, this data revealed the capabilities and drawbacks of each thiol quantification technique and their correlation with protein structure. [ABSTRACT FROM AUTHOR]

Rituximab is a chimeric monoclonal antibody employed for the treatment of CD20-positive B-cell non-Hodgkin's lymphoma, chronic lymphocytic leukemia, rheumatoid arthritis, granulomatosis with polyangiitis and microscopic polyangiitis. It binds specifically to the CD20 antigen expressed on pre-B and consequently on mature B-lymphocytes of both normal and malignant cells, inhibiting their proliferation through apoptosis, CDC, and ADCC mechanisms. The immunomodulatory activity of rituximab is closely related to critical quality attributes that characterize its chemical composition and spatial configuration, which determine the recognition of CD20 and the binding to receptors or factors involved in its effector functions, while regulating the potential immunogenic response. Herein, we present a physicochemical and biological characterization followed by a pharmacodynamics and immunogenicity study to demonstrate comparability between two products containing rituximab. The physicochemical and biological characterization revealed that both products fit within the same response intervals exhibiting the same degree of variability. With regard to clinical response, both products depleted CD20+ B-cells until posttreatment recovery and no meaningful differences were found in their pharmacodynamic profiles. The evaluation of anti-chimeric antibodies did not show differential immunogenicity among products. Overall, these data confirm that similarity of critical quality attributes results in a comparable immunomodulatory activity. [ABSTRACT FROM AUTHOR]