The FDA's assessment of follow-on protein products: a historical perspective

Comparison of neutralization potency across passive immunotherapy approaches as potential treatments for emerging infectious diseases

The use of passive immunotherapy, either as plasma or purified antibodies, has been recommended to treat the emerging infectious diseases (EIDs) in the absence of alternative therapeutic options. Here, we compare the neutralization potency of various passive immunotherapy approaches designed to provide the immediate neutralizing antibodies as potential EID treatments. To prepare human plasma and purified IgG, we screened and classified individuals into healthy, convalescent, and vaccinated groups against SARS-CoV-2 using qRT-PCR, anti-nucleocapsid, and anti-spike tests. Moreover, we prepared purified IgG from non-immunized and hyperimmunized rabbits against SARS-CoV-2 spike protein. Human and rabbit samples were used to evaluate the neutralization potency by sVNT. All vaccinated and convalescent human plasma and purified IgG groups, as well as purified IgG from hyperimmunized rabbits, had significantly greater levels of spike-specific antibodies than the control groups. Furthermore, when compared to the other groups, the purified IgG from hyperimmunized rabbits exhibited superior levels of neutralizing antibodies, with an IC50 value of 2.08 μg/ml. Additionally, our results indicated a statistically significant positive correlation between the neutralization IC50 value and the positive endpoint concentration of spike-specific antibodies. In conclusion, our study revealed that purified IgG from hyperimmunized animals has greater neutralization potency than other passive immunotherapy methods and may be the most suitable treatment of critically ill patients in EIDs.

Comprehensive characterization of higher order structure changes in methionine oxidized monoclonal antibodies via NMR chemometric analysis and biophysical approaches

The higher order structure (HOS) of monoclonal antibodies (mAbs) is an important quality attribute with strong contribution to clinically relevant biological functions and drug safety. Due to the multi-faceted nature of HOS, the synergy of multiple complementary analytical approaches can substantially improve the understanding, accuracy, and resolution of HOS characterization. In this study, we applied one- and two-dimensional (1D and 2D) nuclear magnetic resonance (NMR) spectroscopy coupled with chemometric analysis, as well as circular dichroism (CD), differential scanning calorimetry (DSC), and fluorescence spectroscopy as orthogonal methods, to characterize the impact of methionine (Met) oxidation on the HOS of an IgG1 mAb. We used a forced degradation method involving concentration-dependent oxidation by peracetic acid, in which Met oxidation is site-specifically quantified by liquid chromatography-mass spectrometry. Conventional biophysical techniques report nuanced results, in which CD detects no change to the secondary structure and little change in the tertiary structure. Yet, DSC measurements show the destabilization of Fab and Fc domains due to Met oxidation. More importantly, our study demonstrates that 1D and 2D NMR and chemometric analysis can provide semi-quantitative analysis of chemical modifications and resolve localized conformational changes with high sensitivity. Furthermore, we leveraged a novel 15N-Met labeling technique of the antibody to directly observe structural perturbations at the oxidation sites. The NMR methods described here to probe HOS changes are highly reliable and practical in biopharmaceutical characterization.

Interchangeability for Biologics is a Legal Distinction in the USA, Not a Clinical One

Biologics are increasingly vital medicines that significantly reduce morbidity as well as mortality, yet access continues to be an issue even in apparently wealthy countries, such as the USA. While patient access is expected to improve with the introduction of biosimilars, misperceptions in a significant part based on terminology continue to make a sustained contribution by biosimilars difficult. Patients are and will continue to suffer needlessly if biosimilars continue to be impugned. Consequently, it is increasingly urgent that semantics are clarified, and in particular, the implication that interchangeable biologics are better biosimilars dismissed. This paper distinguishes between the real differences between biologics that matter clinically to patients and discusses the actual meaning of a US Food and Drug Administration designation of interchangeability for a biosimilar product. This will help highlight where there is need for further Food and Drug Administration education and which stakeholders likely need that education the most.

Therapeutic solutions of human albumin - The possible effect of process-induced molecular alterations on clinical efficacy and safety

Human albumin solutions were developed as therapeutic during the Second World War to address blood loss due to battlefield injury. This indication was based on the recognition that albumin provided most of the oncotic capacity of human plasma. For the succeeding sixty years, this formed the basis for the use of albumin in traumatology and emergency medicine. In more recent times, the pharmacological properties arising from albumin's complex structure have become a focus of attention by clinical researchers. In particular, albumin, through anti-inflammatory and anti-oxidant properties, has been proposed as an agent for the treatment of sepsis, cirrhosis and other inflammatory states. Some evidence for these indications has accrued from a number of small clinical trials and observational studies. These studies have not been confirmed in other large trials. Together with other investigators, we have shown that the process of plasma fractionation results in alterations in the structure of albumin, including those parts of the molecule involved in anti-oxidant and anti-inflammatory effects. Albumin products from diverse manufacturers show heterogeneity in their ability to address these effects. In this article, we review the historical development of albumin solutions, pointing out the variations in fractionation chemistries which different manufacturers have adopted. We suggest ways by which the manufacturing processes have contributed to variations in the physico-chemical properties of molecule. We review the outcomes of clinical studies assessing the role of albumin in ameliorating conditions such as sepsis and cirrhosis, and we speculate as to the extent which heterogeneity in the products may have contributed to variable clinical outcomes. Finally, we argue for a change in the perception of the plasma product industry and its regulatory overseers. Historically, albumin has been viewed as a generic commodity, with different preparations being interchangeable in their clinical application. We suggest that this implied biosimilarity is not necessarily applicable for different albumin solutions. The use of albumin, in indications other than its historical role as a plasma expander, can only be validated by clinical investigation of each separate albumin product.

Trastuzumab in breast cancer treatment: the Era of biosimilars

BACKGROUND

The discovery of trastuzumab as anti-HER2 therapy markedly improved disease control and the survival rates of patients with HER2+ breast cancer. However, as trastuzumab is considered a complex molecule, the cost of production is usually elevated, which significantly affects health budgets and limits the treatment access for patients who live in underdeveloped countries. Recently, trastuzumab production became more accessible and sustainable due to the patents' expiration, allowing biosimilar versions of trastuzumab to be developed.

OBJECTIVE

Our main goal was to shed more light on the uses of biosimilars in breast cancer treatment, emphasizing trastuzumab.

METHOD

An integrative review was carried out in the PubMed, Scielo, Web of Science, and SCOPUS databases using the terms "biosimilar," "breast cancer," "monoclonal antibody," and "trastuzumab." The time range included scientific articles published from 2015 to 2021.

RESULTS AND DISCUSSION

The bibliographic survey showed the complexities in biological medicine manufacturing and how the monoclonal antibody's therapy with trastuzumab improved the patients' life expectancy, revolutionizing HER2+ breast cancer treatment. Nonetheless, despite its benefits, trastuzumab generates certain restrictions, especially from the economic perspective. Trastuzumab biosimilars have high selectivity and rarely cause adverse effects compared to conventional chemotherapy.

CONCLUSION

This study shows that trastuzumab biosimilars improve patients' accessibility to breast cancer treatment through a safe and effective therapy compared to the drug reference.

Evaluating Use Cases for Human Challenge Trials in Accelerating SARS-CoV-2 Vaccine Development

Human challenge trials (HCTs) have been proposed as a means to accelerate SARS-CoV-2 vaccine development. We identify and discuss three potential use cases of HCTs in the current pandemic: evaluating efficacy, converging on correlates of protection, and improving understanding of pathogenesis and the human immune response. We outline the limitations of HCTs and find that HCTs are likely to be most useful for vaccine candidates currently in preclinical stages of development. We conclude that, while currently limited in their application, there are scenarios in which HCTs would be extremely beneficial. Therefore, the option of conducting HCTs to accelerate SARS-CoV-2 vaccine development should be preserved. As HCTs require many months of preparation, we recommend an immediate effort to (1) establish guidelines for HCTs for COVID-19; (2) take the first steps toward HCTs, including preparing challenge virus and making preliminary logistical arrangements; and (3) commit to periodically re-evaluating the utility of HCTs.

More comprehensive standards for monitoring glycosylation

Biologics manufacturers must continually monitor the attachment of carbohydrates, called glycans, to their products, because any variability can impact safety and efficacy. To help the industry meet this challenge, the United States Pharmacopeial Convention (USP) offers glycan reference standards and validated methods for glycoprofiling using high-performance liquid chromatography (HPLC). The industry has recently adopted more advanced technologies for glycan analysis, including ultra-high performance liquid chromatography (UHPLC) and mass spectrometry. In this study, we confirm that USP's glycan reference standards are compatible with UHPLC by demonstrating comparable peak separation and glycan identification to HPLC methods. The improved resolving power and shorter run-times of UHPLC also allowed us to identify many of the minor glycan components present in USP's glycan reference standards. These more comprehensively characterized glycan reference standards will enable manufacturers to assess the micro-heterogeneity that can negatively impact the safety and efficacy of biological products.

An NMR-Based Similarity Metric for Higher Order Structure Quality Assessment Among U.S. Marketed Insulin Therapeutics

Protein or peptide higher order structure (HOS) is a quality attribute that could affect therapeutic efficacy and safety. Where appropriate, the HOS similarity between a proposed follow-on product and the reference listed drug should be demonstrated during regulatory assessment. Establishing quantitative HOS similarity for 2 drug substances, manufactured by different processes, has been challenging. Herein, HOS differences among U.S. marketed insulin drug products (DPs) were quantified using nuclear magnetic resonance spectra and principal component analysis (PCA). Then, the unitless Mahalanobis distance (D_M) in PCA space was calculated between insulin analog reference listed drugs and their recently approved follow-on products, and all D_M values were 3.29 or less. By contrast, a larger D_M value of 20.5 was obtained between the 2 insulin human DPs independently approved. However, upon mass-balanced and reversible dialysis of the 2 insulin human DPs against the same buffers, the D_M value was reduced to 1.19 or less. Thus, the observed range of nuclear magnetic resonance-PCA-derived D_M values can be used as a robust and sensitive measure of HOS similarity. Overall, the D_M values of 3.3 for DP and 1.2 for drug substances using insulin therapeutics represented realistic and achievable similarity metrics for developing generic or biosimilar drugs, quality assurance, or control.

Characterization of therapeutic antibodies in the presence of human serum proteins by AU-FDS analytical ultracentrifugation

The preclinical characterization of biopharmaceuticals seeks to determine the stability, state of aggregation, and interaction of the antibody/drug with other macromolecules in serum. Analytical ultracentrifugation is the best experimental method to understand these factors. Sedimentation velocity experiments using the AU-FDS system were performed in order to quantitatively characterize the nonideality of fluorescently labeled therapeutic antibodies in high concentrations of human serum proteins. The two most ubiquitous serum proteins are human serum albumin, HSA, and γ-globulins, predominantly IgG. Tracer experiments were done pairwise as a function of HSA, IgG, and therapeutic antibody concentration. The sedimentation coefficient for each fluorescently labeled component as a function of the concentration of the unlabeled component yields the hydrodynamic nonideality (k_s). This generates a 3x3 matrix of k_s values that describe the nonideality of each pairwise interaction. The k_s matrix is validated by fitting both 2:1 mixtures of HSA (1-40 mg/ml) and IgG (0.5-20 mg/ml) as serum mimics, and human serum dilutions (10-100%). The data are well described by SEDANAL global fitting with the k_s nonideality matrix. The k_s values for antibodies are smaller than expected and appear to be masked by weak association. Global fitting to a k_s and K₂ model significantly improves the fits.

Comparison of NMR and Dynamic Light Scattering for Measuring Diffusion Coefficients of Formulated Insulin: Implications for Particle Size Distribution Measurements in Drug Products

Particle size distribution, a measurable physicochemical quantity, is a critical quality attribute of drug products that needs to be controlled in drug manufacturing. The non-invasive methods of dynamic light scattering (DLS) and Diffusion Ordered SpectroscopY (DOSY) NMR can be used to measure diffusion coefficient and derive the corresponding hydrodynamic radius. However, little is known about their use and sensitivity as analytical tools for particle size measurement of formulated protein therapeutics. Here, DLS and DOSY-NMR methods are shown to be orthogonal and yield identical diffusion coefficient results for a homogenous monomeric protein standard, ribonuclease A. However, different diffusion coefficients were observed for five insulin drug products measured using the two methods. DOSY-NMR yielded an averaged diffusion coefficient among fast exchanging insulin oligomers, ranging between dimer and hexamer in size. By contrast, DLS showed several distinct species, including dimer, hexamer, dodecamer and other aggregates. The heterogeneity or polydisperse nature of insulin oligomers in formulation caused DOSY-NMR and DLS results to differ from each other. DLS measurements provided more quality attributes and higher sensitivity to larger aggregates than DOSY-NMR. Nevertheless, each method was sensitive to a different range of particle sizes and complemented each other. The application of both methods increases the assurance of complex drug quality in this similarity comparison.

Assessing the Immunogenicity of Biopharmaceuticals

Biopharmaceuticals have the potential to raise an immunogenic response in treated individuals, which may impact the efficacy and safety profile of these drugs. As a result, it is essential to evaluate immunogenicity throughout the different phases of the clinical development of a biopharmaceutical, including post-marketing surveillance. Although rigorous evaluation of biopharmaceutical immunogenicity is required by regulatory authorities, there is a lack of uniform standards for the type, quantity, and quality of evidence, and for guidance on experimental design for immunogenicity assays or criteria to compare immunogenicity of biopharmaceuticals. Moreover, substantial technological advances in methods to assess immune responses have yielded higher immunogenicity rates with modern assays, and limit comparison of immunogenicity of biopharmaceuticals outside of head-to-head clinical trials. Accordingly, research programs, regulatory agencies, and clinicians need to keep pace with continuously evolving analyses of immunogenicity. Here, we review factors associated with immunogenicity of biopharmaceuticals, potential clinical ramifications, and current regulatory guidance for evaluating immunogenicity, and discuss methods to assess immunogenicity in non-clinical and clinical studies. We also describe special considerations for evaluating the immunogenicity of biosimilar candidates.

Position Paper from the Portuguese Association of Hospital Pharmacists for biosimilar therapeutic antibodies

WHAT IS KNOWN AND OBJECTIVE

Biopharmaceuticals are an important class of drugs for the treatment of autoimmune/inflammatory and oncologic diseases. With patent expiries, biotechnological manufacturers can now develop biosimilar drugs. Due to timeliness of introducing new and more complex biosimilars, the Portuguese Association of Hospital Pharmacists gathered to develop a common positioning on the use of biosimilar monoclonal antibodies.

MAIN ISSUES

The European pathway to biosimilar approval was developed to improve affordability and access to biological therapies, but it remains a work in progress because unresolved issues remain. Due to the present reality of biosimilar monoclonal antibodies, hospital pharmacists must play an important role in ensuring the safe, effective and cost-effective use of biosimilars in health systems; and educating healthcare administrators, providers, legislators, policymakers, payors and patients about these products.

WHAT IS NEW AND CONCLUSION

The conclusions presented in this work focused on the proposal for optimal biosimilar prescription criteria, the preparation of original biologics and biosimilars in the pharmacy, the management and selection of suppliers, extrapolation issues, the specific role of pharmacovigilance and risk management for the optimal use of biosimilar monoclonal antibodies.

Biosimilars: The US Regulatory Framework

With the passage of the Biologics Price Competition and Innovation Act of 2009, the US Food and Drug Administration established an abbreviated pathway for developing and licensing biosimilar and interchangeable biological products. The regulatory framework and the technical requirements of the US biosimilars program involve a stepwise approach that relies heavily on analytical methods to demonstrate through a "totality of the evidence" that a proposed product is biosimilar to its reference product. By integrating analytical, pharmacological, and clinical data, each of which has limitations, a high level of confidence can be reached regarding clinical performance. Although questions and concerns about the biosimilars pathway remain and may slow uptake, a robust scientific program has been put in place. With three biosimilars already licensed and numerous development programs under way, clinicians can expect to see many new biosimilars come onto the US market in the coming decade. [Note added in proof: Since the writing of this article, a fourth biosimilar has been approved.].

Considerations in the development of generic disease therapies for multiple sclerosis

PURPOSE OF REVIEW

Medication prices are a major contributor to the high cost of care for multiple sclerosis (MS). The patents for some of the initial injectable therapies for relapsing MS recently expired, permitting development, regulatory approval, and marketing of generic alternatives with the potential for lower prices and cost savings to payers and patients.

RECENT FINDINGS

A generic version of glatiramer acetate 20 mg administered by daily subcutaneous injection recently received regulatory approval in the United States. Two additional generic versions of glatiramer acetate have been submitted for regulatory review. The development and testing of generic disease-modifying therapies for MS such as glatiramer acetate, which are complex molecules, present several complicating factors.

SUMMARY

This article provides background on the development of generics and reviews the status of generic glatiramer acetate.

Simple NMR methods for evaluating higher order structures of monoclonal antibody therapeutics with quinary structure

Monoclonal antibody (mAb) drugs constitute the largest class of protein therapeutics currently on the market. Correctly folded protein higher order structure (HOS), including quinary structure, is crucial for mAb drug quality. The quinary structure is defined as the association of quaternary structures (e.g., oligomerized mAb). Here, several commonly available analytical methods, i.e., size-exclusion-chromatography (SEC) FPLC, multi-angle light scattering (MALS), circular dichroism (CD), NMR and multivariate analysis, were combined and modified to yield a complete profile of HOS and comparable metrics. Rituximab and infliximab were chosen for method evaluation because both IgG1 molecules are known to be homologous in sequence, superimposable in Fab crystal structure and identical in Fc structure. However, herein the two are identified to be significantly different in quinary structure in addition to minor secondary structure differences. All data collectively showed rituximab was mostly monomeric while infliximab was in mono-oligomer equilibrium driven by its Fab fragment. The quinary structure differences were qualitatively inferred from the less used but more reproducible dilution-injection-SEC-FPLC curve method. Quantitative principal component analysis (PCA) was performed on NMR spectra of either the intact or the in-situ enzymatic-digested mAb samples. The cleavage reactions happened directly in NMR tubes without further separation, which greatly enhanced NMR spectra quality and resulted in larger inter- and intra-lot variations based on PCA. The new in-situ enzymatic digestion method holds potential in identifying structural differences on larger therapeutic molecules using NMR.

Evaluation of Ion Mobility-Mass Spectrometry for Comparative Analysis of Monoclonal Antibodies

Analytical techniques capable of detecting changes in structure are necessary to monitor the quality of monoclonal antibody drug products. Ion mobility mass spectrometry offers an advanced mode of characterization of protein higher order structure. In this work, we evaluated the reproducibility of ion mobility mass spectrometry measurements and mobiligrams, as well as the suitability of this approach to differentiate between and/or characterize different monoclonal antibody drug products. Four mobiligram-derived metrics were identified to be reproducible across a multi-day window of analysis. These metrics were further applied to comparative studies of monoclonal antibody drug products representing different IgG subclasses, manufacturers, and lots. These comparisons resulted in some differences, based on the four metrics derived from ion mobility mass spectrometry mobiligrams. The use of collision-induced unfolding resulted in more observed differences. Use of summed charge state datasets and the analysis of metrics beyond drift time allowed for a more comprehensive comparative study between different monoclonal antibody drug products. Ion mobility mass spectrometry enabled detection of differences between monoclonal antibodies with the same target protein but different production techniques, as well as products with different targets. These differences were not always detectable by traditional collision cross section studies. Ion mobility mass spectrometry, and the added separation capability of collision-induced unfolding, was highly reproducible and remains a promising technique for advanced analytical characterization of protein therapeutics. Graphical Abstract ᅟ.

Preparation of honokiol with biodegradable nanoparticles for treatment of osteosarcoma

Hon/MPEG-PCL nanoparticles were parpered by self-assembly method and showed therapeutic potential in the treatment of osteosarcoma.

Progress in biosimilar monoclonal antibody development: the infliximab biosimilar CT-P13 in the treatment of rheumatic diseases

Biosimilars are biologic medical products whose active drug substance is made by a living organism or derived from it. The term is used to describe a subsequent version of an innovator biopharmaceutical product aiming at approval following patent expiry on the reference product. Biosimilars of monoclonal need to demonstrate similar but not identical quality of nonclinical and clinical attributes. Not all data of the originator product need to be recapitulated, as large numbers of patient-years of exposure data are already available. Thus, biosimilar development is largely based on the safety profiles of the originator product. The evaluation of biosimilarity includes immunogenicity attributed risks. CT-P13 (Remsima™/Inflectra™, Celltrion/Hospira), a biosimilar of the innovator drug infliximab (INF), was the first approved complex biosimilar monoclonal antibody in the EU, within the framework of WHO, EMA and US FDA biosimilar guidelines. CT-P13 has shown analytical and nonclinical features highly similar to INF including pharmacokinetics, efficacy, safety and immunogenicity profiles in ankylosing spondylitis and rheumatoid arthritis. The objective of this article is to highlight the recent biosimilar development and to review the results from the studies PLANETRA and PLANETAS, which have supported the approval of CT-P13 for several indications.

Biosimilars in dermatology

Over the last decade the availability of biological drugs for the treatment of psoriasis vulgaris, psoriatic arthritis and many other inflammatory diseases has revolutionized the treatment of these diseases around the world. Due to the high cost of therapy, the search has started for biosimilars. In dermatology the greatest interest in biosimilar medicines concerns inhibitors of tumor necrosis factor a (TNF-α), for use in the treatment of psoriasis vulgaris and psoriatic arthritis (infliximab, etanercept, adalimumab). The most important element of the safety of biologicals is their immunogenicity. Therefore, when discussing biosimilars, attention needs to be paid to the dangers of their immune activity. In view of the fact that the drugs contain and aggregates, produced by living organisms or cultures of living cells, they cannot be compared in any way to low molecular weight synthetic generics (called generics). Biosimilars are authorized for use in patients and treated as equivalent to the reference medicine only after passing a number of studies and assessments. As it is well known, the development of medicine and pharmacology is extremely intense, and the market in biological medicine is developing much faster than that of all other drugs, which underlines their important role in modern medicine. Currently, the subject of biosimilars is one of the most important challenges and topics of discussion around the world, including pharmacovigilance and legal and economic regulatory standards. It seems inevitable that biosimilar products will be introduced for the treatment of diseases with indications corresponding to the original product on which they are based.

Physicochemical characterization of Remsima

Remsima® (infliximab) was recently approved as the world's first biosimilar monoclonal antibody (mAb) in both the European Union and Korea. To achieve this, extensive physicochemical characterization of Remsima® in relation to Remicade® was conducted in order to demonstrate the highly similar properties between the two molecules. A multitude of state-of-the-art analyses revealed that Remsima® has identical primary as well as indistinguishable higher order structures compared with the original product. Monomer and aggregate contents of Remsima® were also found to be comparable with those of Remicade®. In terms of charge isoforms, although Remsima® was observed to contain slightly less basic variants than the original antibody, the difference was shown to be largely due to the presence of C-terminal lysine. On the other hand, this lysine was found to be rapidly clipped inside serum in vitro and in vivo, suggesting it has no effect on the biological potency or safety of the drug. Analysis of the glycan contents of the antibodies showed comparable glycan types and distributions. Recent results of clinical studies have further confirmed that the two antibody products are highly similar to each other. Based on this research as well as previous clinical and non-clinical comparability studies, Remsima® can be considered as a highly similar molecule to Remicade® in terms of physicochemical properties, efficacy, and safety for its final approval as a biosimilar product to Remicade®.

Predicting Hemagglutinin MHC-II Ligand Analogues in Anti-TNFα Biologics: Implications for Immunogenicity of Pharmaceutical Proteins

The purpose of this study was to evaluate the extent of overlapping immunogenic peptides between three pharmaceutical biologics and influenza viruses. Clinical studies have shown that subsets of patients with rheumatoid arthritis (RA) develop anti-drug antibodies towards anti-TNFα biologics. We postulate that common infectious pathogens, including influenza viruses, may sensitize RA patients toward recombinant proteins. We hypothesize that embedded within infliximab (IFX), adalimumab (ADA), and etanercept (ETN) are ligands of class II major histocompatibility complex (MHC-II) that mimic T cell epitopes derived from influenza hemagglutinin (HA). The rationale is that repeated administration of the biologics would reactivate HA-primed CD4 T cells, stimulating B cells to produce cross-reactive antibodies. Custom scripts were constructed using MATLAB to compare MHC-II ligands of HA and the biologics; all ligands were predicted using tools in Immune Epitope Database and Resources (IEDB). We analyzed three HLA-DR1 alleles (0101, 0401 and 1001) that are prominent in RA patients, and two alleles (0103 and 1502) that are not associated with RA. The results indicate that 0401 would present more analogues of HA ligands in the three anti-TNFα biologics compared to the other alleles. The approach led to identification of potential ligands in IFX and ADA that shares sequence homology with a known HA-specific CD4 T cell epitope. We also discovered a peptide in the complementarity-determining region 3 (CDR-3) of ADA that encompasses both a potential CD4 T cell epitope and a known B cell epitope in HA. The results may help generate new hypotheses for interrogating patient variability of immunogenicity of the anti-TNFα drugs. The approach would aid development of new recombinant biologics by identifying analogues of CD4 T cell epitopes of common pathogens at the preclinical stage.

Herpes murine model as a biological assay to test dialyzable leukocyte extracts activity

Human dialyzable leukocyte extracts (DLEs) are heterogeneous mixtures of low-molecular-weight peptides that are released on disruption of peripheral blood leukocytes from healthy donors. DLEs improve clinical responses in infections, allergies, cancer, and immunodeficiencies. Transferon is a human DLE that has been registered as a hemoderivate by Mexican health authorities and commercialized nationally. To develop an animal model that could be used routinely as a quality control assay for Transferon, we standardized and validated a murine model of cutaneous HSV-1 infection. Using this model, we evaluated the activity of 27 Transferon batches. All batches improved the survival of HSV-1-infected mice, wherein average survival rose from 20.9% in control mice to 59.6% in Transferon-treated mice. The activity of Transferon correlated with increased serum levels of IFN-γ and reduced IL-6 and TNF-α concentrations. Our results demonstrate that (i) this mouse model of cutaneous herpes can be used to examine the activity of DLEs, such as Transferon; (ii) the assay can be used as a routine test for batch release; (iii) Transferon is produced with high homogeneity between batches; (iv) Transferon does not have direct virucidal, cytoprotective, or antireplicative effects; and (v) the protective effect of Transferon in vivo correlates with changes in serum cytokines.

Botulinum toxin type A products are not interchangeable: a review of the evidence

Botulinum toxin type A (BoNTA) products are injectable biologic medications derived from Clostridium botulinum bacteria. Several different BoNTA products are marketed in various countries, and they are not interchangeable. Differences between products include manufacturing processes, formulations, and the assay methods used to determine units of biological activity. These differences result in a specific set of interactions between each BoNTA product and the tissue injected. Consequently, the products show differences in their in vivo profiles, including preclinical dose response curves and clinical dosing, efficacy, duration, and safety/adverse events. Most, but not all, published studies document these differences, suggesting that individual BoNTA products act differently depending on experimental and clinical conditions, and these differences may not always be predictable. Differentiation through regulatory approvals provides a measure of confidence in safety and efficacy at the specified doses for each approved indication. Moreover, the products differ in the amount of study to which they have been subjected, as evidenced by the number of publications in the peer-reviewed literature and the quantity and quality of clinical studies. Given that BoNTAs are potent biological products that meet important clinical needs, it is critical to recognize that their dosing and product performance are not interchangeable and each product should be used according to manufacturer guidelines.

Frontiers in nonclinical drug development: biosimilars

Biopharmaceuticals, produced by recombinant DNA technology, are generally more complicated to produce than small molecule drugs. As patents around the development and manufacturing of these biopharmaceuticals expire, biosimilars are being developed as comparable and more affordable alternatives to improve patient access and market competition. This commentary explains what a biosimilar is; it compares and contrasts biosimilar production with that of small molecule, generic, and other biological drugs; and it describes basic principles of the nonclinical development program for monoclonal antibody biosimilars.

Choice of Fluids in Severe Septic Patients - A Cost-effectiveness Analysis Informed by Recent Clinical Trials

Fluid resuscitation with colloids is an established second line therapy for septic patients. Evidence of relative efficacy outcomes is tempered by considerations of the relative costs of the individual fluids. An assessment of recent large clinical trials was performed, resulting in a ranking in the efficacy of these therapies. Probabilities for mortality and the need for renal replacement therapy (RRT) were derived and used to inform a decision analysis model comparing the effect of crystalloid, albumin and hydroxyethyl starch solutions in severe septic patients followed from hospital admission to 90 days in intensive care. The US payer perspective was used. Model inputs for costs and efficacy were derived from the peer-reviewed literature, assuming that that all fluid preparations are bio-equivalent within each class of these therapies. Probabilities for mortality and the need for renal replacement therapy (RRT) data were synthesized using a Bayesian meta-analysis. Relative to crystalloid therapy, 0.21 life years were gained with albumin and 0.85 life years were lost with hydroxyethyl starch. One-way sensitivity analysis showed that the model's outcomes were sensitive to the cost of RRT but not to the costs of the actual fluids or any other costs. We conclude that albumin may be the most cost-effective treatment in these patients when the total medical costs and iatrogenic morbidities involved in treating sepsis with fluids are considered. These results should assist and inform decision making in the choice of these drugs.

Improving the anti-colon cancer activity of curcumin with biodegradable nano-micelles

Curcumin (Cur) showed an antitumor effect by anti-angiogenesis and the induction of apoptosis. However, curcumin is limited in clinical applications by its hydrophobicity. Therefore, improving the water-solublilty and antitumor effect of curcumin are very meaningful. In this work, biodegradable monomethoxy poly(ethylene glycol)poly(lactide) copolymer (MPEG-PLA) micelles were employed to deliver curcumin by a self-assembly method. The obtained curcumin loaded polymeric micelles (Cur/MPEG-PLA) with a drug loading of 8% were monodisperse and ∼30 nm in diameter, which could release curcumin in an extended period in vitro and in vivo. In addition, Cur/MPEG-PLA showed a larger effect on cell growth inhibition and the induction of cell apoptosis than free curcumin in vitro. Furthermore, the therapy efficiency of Cur/MPEG-PLA on a colon cancer mouse model was evaluated in detail. Cur/MPEG-PLA could cause a more significant inhibitory effect on colon tumor growth than free curcumin with the same dose (P < 0.05 or P < 0.05, respectively), which indicated that Cur/MPEG-PLA could improve the antitumor effect of curcumin in vivo. Immunohistochemical and immunofluorescent analysis showed that Cur/MPEG-PLA could induce more tumor cell apoptosis, and inhibit more angiogenesis than the free drug group. Besides, Cur/MPEG-PLA exhibited a larger anti-angiogenesis effect in vivo. Finally, the anti-lung metastasis efficiency of Cur/MPEG-PLA on the colon cancer model was evaluated. Cur/MPEG-PLA could cause a more significant inhibitory effect on lung metastasis than free curcumin with the same dose (P < 0.05), which indicates that Cur/MPEG-PLA could improve the anti-lung metastasis effect of curcumin in vivo. Our data suggested Cur/MPEG-PLA may have potential clinical applications in colon cancer therapy.

Complementary MS methods assist conformational characterization of antibodies with altered S-S bonding networks

As therapeutic monoclonal antibodies (mAbs) become a major focus in biotechnology and a source of the next-generation drugs, new analytical methods or combination methods are needed for monitoring changes in higher order structure and effects of post-translational modifications. The complexity of these molecules and their vulnerability to structural change provide a serious challenge. We describe here the use of complementary mass spectrometry methods that not only characterize mutant mAbs but also may provide a general framework for characterizing higher order structure of other protein therapeutics and biosimilars. To frame the challenge, we selected members of the IgG2 subclass that have distinct disulfide isomeric structures as a model to evaluate an overall approach that uses ion mobility, top-down MS sequencing, and protein footprinting in the form of fast photochemical oxidation of proteins (FPOP). These three methods are rapid, sensitive, respond to subtle changes in conformation of Cys → Ser mutants of an IgG2, each representing a single disulfide isoform, and may be used in series to probe higher order structure. The outcome suggests that this approach of using various methods in combination can assist the development and quality control of protein therapeutics.

Rituximab biosimilars

INTRODUCTION

Rituximab is a monoclonal antibody targeting CD20, used to treat B cell malignancies and B cell-mediated autoimmune diseases. Rituximab has the largest market of any monoclonal antibody therapeutic. Its patent will expire within the next few years and several manufacturers have already produced or are developing rituximab biosimilars that aim to match the innovator rituximab as closely as possible.

AREAS COVERED

In this review, we discuss key factors that determine the efficacy of rituximab therapy, potential technical challenges in the manufacture and evaluation of biosimilars, regulatory considerations regarding the review and approval of biosimilars, and the current status of biosimilar rituximab development by various manufacturers. Due to the nature of the topic, literature searches included conference abstracts, regulatory and industry websites as well as peer reviewed literature.

EXPERT OPINION

Cost is a key limitation of current biologics usage and there is a political impetus to the licensing of biosimilars. Concerns regarding potential dissimilarities of biosimilars are legitimate, but surmountable with techniques for in vitro, in vivo and clinical testing and more clearly defined regulatory requirements. These should provide reassurance to prescribers. However, the cost of manufacturing and licensing a biosimilar remains high and the reduction in cost may be more limited than for a non-biologic small molecule drug and its generic version. This cost reduction will be critical to the impact and use of rituximab biosimilars.

US Food and Drug Administration approval of generic versions of complex biologics: implications for the practicing physician using low molecular weight heparins

Low-molecular-weight heparins (LMWHs) have shown equivalent or superior efficacy and safety to unfractionated heparin as antithrombotic therapy for patients with acute coronary syndromes. Each approved LMWH is a pleotropic biological agent with a unique chemical, biochemical, biophysical and biological profile and displays different pharmacodynamic and pharmacokinetic profiles. As a result, LMWHs are neither equipotent in preclinical assays nor equivalent in terms of their clinical efficacy and safety. Previously, the US Food and Drug Administration (FDA) cautioned against using various LMWHs interchangeably, however recently, the FDA approved generic versions of LMWH that have not been tested in large clinical trials. This paper highlights the bio-chemical and pharmacological differences between the LMWH preparations that may result in different clinical outcomes, and also reviews the implications and challenges physicians face when generic versions of the original/innovator agents are approved for clinical use.

Comparative signature diagrams to evaluate biophysical data for differences in protein structure across various formulations

A solution to the problem of being able to show statistically significant differences in the measurements of various levels of higher-order protein structure has been an elusive one. We propose the use of comparative signature diagrams (CSDs) to this end. CSDs compare datasets from different biophysical techniques that fingerprint the secondary, tertiary, and quaternary structures of a protein molecule and display statistically significant differences in these datasets. In this paper, we explore the differences in the structures of two proteins (Granulocyte Colony Stimulating Factor [GCSF] and a monoclonal antibody [mAb]) in various formulations. These proteins were chosen based on the extent of differences in structure observed in the formulations. As an initial test, we utilize data from circular dichroism, 8-anilino-1-naphthalene-sulfonate and intrinsic fluorescence spectroscopy, and static light scattering measurements to fingerprint protein structure in the different formulations. Several layers of statistics were explored to visualize the regions of significant differences in the protein spectra. This approach provides a rapid, high-resolution methodology to compare various structural levels of proteins using standard biophysical instrumentation.

Challenges and opportunities in absorption, distribution, metabolism, and excretion studies of therapeutic biologics

With the advancement of biotechnology in the last two decades, optimized and novel modalities and platforms of biologic moieties have emerged rapidly in drug discovery pipelines. In addition, new technologies for delivering therapeutic biologics (e.g., needle-free devices, nanoparticle complexes), as well as novel approaches for disease treatments (e.g., stem cell therapy, individualized medicine), continue to be developed. While pharmacokinetic studies are routinely carried out for therapeutic biologics, experiments that elucidate underlying mechanisms for clearance and biodistribution or identify key factors that govern absorption, distribution, metabolism, and excretion (ADME) of biologics often are not thoroughly conducted. Realizing the importance of biologics as therapeutic agents, pharmaceutical industry has recently begun to move the research focus from small molecules only to a blended portfolio consisting of both small molecules and biologics. This trend brings many opportunities for scientists working in the drug disposition research field. In anticipation of these opportunities and associated challenges, this review highlights impact of ADME studies on clinical and commercial success of biologics, with a particular focus on emerging applications and technologies and linkage with mechanistic pharmacokinetic/pharmacodynamic modeling and biomarker research.

Analytical tools for characterizing biopharmaceuticals and the implications for biosimilars

Biologics such as monoclonal antibodies are much more complex than small-molecule drugs, which raises challenging questions for the development and regulatory evaluation of follow-on versions of such biopharmaceutical products (also known as biosimilars) and their clinical use once patent protection for the pioneering biologic has expired. With the recent introduction of regulatory pathways for follow-on versions of complex biologics, the role of analytical technologies in comparing biosimilars with the corresponding reference product is attracting substantial interest in establishing the development requirements for biosimilars. Here, we discuss the current state of the art in analytical technologies to assess three characteristics of protein biopharmaceuticals that regulatory authorities have identified as being important in development strategies for biosimilars: post-translational modifications, three-dimensional structures and protein aggregation.