Polymersomes for protein drug delivery across intestinal mucosa

The oral administration is the route preferred by patients due to its multiple advantages. In the case of biopharmaceuticals, due to their low stability and absorption in the intestine, these molecules must be administered by injectable routes. To circumvent these problems, several strategies have been studied, among which the use of nanosystems, such as polymersomes, can be highlighted. In this work the potential of poloxamer 401 polymersomes as a system for oral delivery of antibodies was evaluated. IgG-FITC-loaded poloxamer 401 polymerosomes were initially used to assess whether it improves intestinal epithelial permeation in Caco-2 cell monolayers. Subsequently, epithelial/macrophage co-culture model was used to evaluate the ability of poloxamer 401 polymersomes containing adalimumab to reduce proinflammatory cytokine levels. The data showed that polymersome-encapsulated IgG increased the transport across intestinal Caco-2 monolayers 2.7-fold compared to the antibody in solution. Also, when comparing the groups of blank polymersomes with polymersomes containing adalimumab, decreases of 1.5-, 5.5-, and 2.4-fold in TNF-α concentrations were observed for the polymersomes containing 1.5, 3.75, and 15 µg/mL of adalimumab, respectively. This could indicate a possibility for the oral administration of biopharmaceuticals which would revolutionize many conditions that require the systemic administration such as in inflammatory bowel disease.

SCEL regulates switches between pro-survival and apoptosis of the TNF-α/TNFR1/NF-κB/c-FLIP axis to control lung colonization of triple negative breast cancer

BACKGROUND

Patients with metastatic triple-negative breast cancer (mTNBC) have a higher probability of developing visceral metastasis within 5 years after the initial diagnosis. Therefore, a deeper understanding of the progression and spread of mTNBC is urgently needed.

METHODS

The isobaric tag for relative and absolute quantitation (iTRAQ)-based LC-MS/MS proteomic approach was applied to identify novel membrane-associated proteins in the lung-tropic metastatic cells. Public domain datasets were used to assess the clinical relevance of the candidate proteins. Cell-based and mouse models were used for biochemical and functional characterization of the protein molecule Sciellin (SCEL) identified by iTRAQ to elucidate its role and underlying mechanism in promoting lung colonization of TNBC cells.

RESULTS

The iTRAQ-based LC-MS/MS proteomic approach identified a membrane-associated protein SCEL that was overexpressed in the lung-tropic metastatic cells, and its high expression was significantly correlated with the late-stage TNBC and the shorter survival of the patients. Downregulation of SCEL expression significantly impaired the 3D colony-forming ability but not the migration and invasion ability of the lung colonization (LC) cells. Knockdown of SCEL reduced TNF-α-induced activation of the NF-κB/c-FLIP pro-survival and Akt/Erk1/2 growth signaling pathways in the LC cells. Specifically, knockdown of SCEL expression switched TNF-α-mediated cell survival to the caspase 3-dependent apoptosis. Conversely, ectopic expression of SCEL promoted TNF-α-induced activation of NF-κB/c-FLIP pro-survival and Akt/Erk1/2 pro-growth signaling pathway. The result of co-immunoprecipitation (Co-IP) and GST pull-down assay showed that SCEL could interact with TNFR1 to promote its protein stability. The xenograft mouse model experiments revealed that knockdown of SCEL resulted in increase of caspase-3 activity, and decrease of ki67 and TNFR1 expression as well as increase of tumor-associated macrophages in the metastatic lung lesions. Clinically, SCEL expression was found to be positively correlated with TNFR1 in TNBC tissues. Lastly, we showed that blocking TNF-α-mediated cell survival signaling by adalimumab effectively suppressed the lung colonization of the SCEL-positive, but not the SCEL-downregulated LC cells in the tail-vein injection model.

CONCLUSIONS

Our findings indicate that SCEL plays an essential role in the metastatic lung colonization of TNBC by promoting the TNF-α/TNFR1/NF-κB/c-FLIP survival and Akt/Erk1/2 proliferation signaling. Thus, SCEL may serve as a biomarker for adalimumab treatment of TNBC patients.

A mechanistic pharmacokinetic model with drug and antidrug antibody interplay, and its application for assessing the impact of immunogenicity response on bioequivalence testing

AIMS

Single-dose pharmacokinetic (PK) studies in healthy subjects have been the design of choice for bioequivalence determination for decades. This preference has been recently extended to PK similarity studies of proposed biosimilars. However, PK similarity studies can be complicated by the effect of immunogenicity response on drug disposition. The impact is exacerbated when there is an imbalance in host-specific immunological characteristics of subjects between the test and reference groups. Such complications remain poorly understood. The purpose of this communication is to show that the impact of immunogenicity response on PK similarity determination can be critical, using adalimumab as an example.

METHODS

Data for adalimumab concentrations and immunogenicity response over 10 weeks were obtained from 133 healthy subjects receiving a 40 mg dose of Humira® in a PK similarity study. Also, a population PK model with a mechanistic construct for delineating the interplay between adalimumab disposition and antidrug antibodies response was utilized to estimate via simulation the probability that a PK similarity study would fail in typical study settings.

RESULTS

The simulations showed that the immunogenicity response can have a profound impact on the outcome of PK similarity determination. As such, the probability of failing to achieve the similarity conclusion increased to 51.9%, from 13.8% in the absence of immunogenicity response.

CONCLUSION

This study provides a model-based framework for better understanding of how a PK similarity study can be optimally designed and for interpretation of the outcome of PK similarity determination when the drug disposition is affected in the presence of immunogenicity response.

Stable Expression of Adalimumab in Nicotiana tabacum

Production of monoclonal antibodies and pharmaceutical proteins in transgenic plants has been the focus of many research efforts for close to 30 years. Use of plants as bioreactors reduces large-scale production costs and minimizes risk for human pathogens contamination. Stable nuclear transformation of the plant genome offers a clear advantage in agricultural protein production platforms, limited only by the number of hectares that can be cultivated. We report here, for the first time, successful and stable expression of adalimumab in transgenic Nicotiana tabacum plants. The plant-derived adalimumab proved fully active and was shown to rescue L929 cells from the in vitro lethal effect of rhTNFα just as effectively as commercially available CHO-derived adalimumab (Humira). These results indicate that agricultural biopharming is an efficient alternative to mammalian cell-based expression platforms for the large-scale production of recombinant antibodies.

Demonstration of Functional Similarity of Proposed Biosimilar ABP 501 to Adalimumab

BACKGROUND

Due to the complex molecular structure and proprietary manufacturing processes of monoclonal antibodies (mAbs), differences in structure and function may be expected during development of biosimilar mAbs. Important regulatory requirements for approval of biosimilar products involve comprehensive assessments of any potential differences between proposed biosimilars and reference mAbs, including differences in all known mechanisms of action, using sensitive and relevant methods. Any identified structural differences should not result in differences in biofunctional or clinical activity.

OBJECTIVE

A comprehensive assessment comparing the Amgen biosimilar candidate ABP 501 with FDA-licensed adalimumab (adalimumab [US]) and EU-authorized adalimumab (adalimumab [EU]) was conducted to demonstrate similarity in biofunctional activity.

METHODS

The functional similarity assessment included testing of binding kinetics to soluble tumor necrosis factor α (TNFα) and relative binding to transmembrane TNFα. The neutralization of TNFα-induced caspase activation, TNFα- and lymphotoxin-α (LTα)-induced chemokine production, and cytotoxicity was also tested. Binding to Fc-gamma receptors FcγRIa, FcγRIIa (131H), FcγRIIIa (158V and 158F), and neonatal Fc receptor (FcRn) was compared with the reference mAbs, as was antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity.

RESULTS

The data demonstrate that ABP 501 is similar to both adalimumab (US) and adalimumab (EU) with respect to evaluated biofunctional activities.

CONCLUSION

Similarity in biofunctional activity is a critical component of the totality of evidence required for demonstration of biosimilarity. The functional similarity demonstrated for ABP 501 comprehensively assesses the known mechanisms of action of adalimumab, supporting the conclusion that ABP 501, adalimumab (US), and adalimumab (EU) are likely to be clinically similar.

Whole cell-based surface plasmon resonance measurement to assess binding of anti-TNF agents to transmembrane target

We developed a technique for the measurement of surface plasmon resonance (SPR) to detect interactions of anti-tumor necrosis factor (TNF) agents with transmembrane TNF-α (mTNF-α) on living whole cells. The injection of a suspension of mTNF-α expressing Jurkat cells, used as an analyte, gave a clear binding response to anti-TNF agents, such as etanercept, infliximab and adalimumab, immobilized on sensorchip. The binding response of the analyte cells increased in a concentration-dependent manner and was competitively reduced by adding soluble TNF receptors to the analyte cell suspension. Treatment of analyte cells with free anti-TNF agent before injection reduced the binding response between the analyte cells and immobilized-etanercept on sensorchip, and the inhibitory effect of free anti-TNF agent was concordant with the affinity of anti-TNF agent for soluble TNF-α. These findings indicate that the SPR response arises from specific binding between anti-TNF agent and its target on cell membrane.

Certolizumab pegol does not bind the neonatal Fc receptor (FcRn): Consequences for FcRn-mediated in vitro transcytosis and ex vivo human placental transfer

Antibodies to tumor necrosis factor (anti-TNF) are used to treat inflammatory diseases, which often affect women of childbearing age. The active transfer of these antibodies across the placenta by binding of the Fc-region to the neonatal Fc receptor (FcRn) may result in adverse fetal or neonatal effects. In contrast to other anti-TNFs, certolizumab pegol lacks an Fc-region. The objective of this study was to determine whether the structure of certolizumab pegol limits active placental transfer. Binding affinities of certolizumab pegol, infliximab, adalimumab and etanercept to human FcRn and FcRn-mediated transcytosis were determined using in vitro assays. Human placentas were perfused ex vivo to measure transfer of certolizumab pegol and positive control anti-D IgG from the maternal to fetal circulation. FcRn binding affinity (KD) was 132nM, 225nM and 1500nM for infliximab, adalimumab and etanercept, respectively. There was no measurable certolizumab pegol binding affinity, similar to that of the negative control. FcRn-mediated transcytosis across a cell layer (mean±SD; n=3) was 249.6±25.0 (infliximab), 159.0±20.2 (adalimumab) and 81.3±13.1ng/mL (etanercept). Certolizumab pegol transcytosis (3.2±3.4ng/mL) was less than the negative control antibody (5.9±4.6ng/mL). No measurable transfer of certolizumab pegol from the maternal to the fetal circulation was observed in 5 out of 6 placentas that demonstrated positive-control IgG transport in the ex vivo perfusion model. Together these results support the hypothesis that the unique structure of certolizumab pegol limits its transfer through the placenta to the fetus and may be responsible for previously reported differences in transfer of other anti-TNFs from mother to fetus.