[Biosimilars versus original biologics. Similarities and differences from development to approval]. / Biosimilars versus Erstanbieterbiologika. Gemeinsamkeiten und Unterschiede von der Entwicklung bis zur Zulassung.

BACKGROUND: Due to the expiry of patents for biological pharmaceuticals, in forthcoming years there will be an increase in the approval of biosimilars by the international health authorities. This will bring potential savings in the range of 11.8-33.4 billion euros in the European Union (EU) in the year 2020. OBJECTIVES: The aims are an understanding of the natural variability of biological substances and the clinical relevance of the diverse product attributes, proof of comparability (similarity) as a self-contained concept in the development and approval of biosimilars and importance of extrapolation to other indications when comparability is demonstrated by comprehensive analytical and functional studies. MATERIAL AND METHODS: This study involved an assessment of the regulations of the European licensing authority, the European Medicines Agency (EMA), with respect to the approval of biosimilars, analytical, physicochemical and biological procedures for determination of comparability and the permissible deviation from the reference product RESULTS: Approved biological pharmaceuticals have a natural intrinsic variability, e.g. with respect to glycosylation. Furthermore, different batches in the manufacturing process can be different or the manufacturing process itself can be subject to change. Biosimilars are subject to specific and strict approval criteria with the aim of restricting the product attributes to lie within the variability range of the original biologics, can only show deviations from the original preparations within very narrow limits and must show proven safety, quality and effectiveness comparable to them. DISCUSSION: The development and approval concept of biosimilars has been proven for nearly 10 years. Strict requirements by the EMA guarantee the highest quality standards, which have led to significant savings in the healthcare system and an expansion of access to biological pharmaceuticals in many countries and for many patients.

Taking immunogenicity assessment of therapeutic proteins to the next level.

Therapeutic proteins provide innovative and effective therapies for numerous diseases. However, some of these products are associated with unwanted immunogenicity that may lead to clinical consequences such as reduced or loss of efficacy, altered pharmacokinetics (PK), general immune and hypersensitivity reactions, and neutralisation of the natural counterpart (e.g. the physiological hormone). Regulatory guidance on immunogenicity assessment needs to take into consideration a great diversity of products, indications and patient populations as well as constantly advancing manufacturing technologies. Such guidance needs to be sufficiently specific while, at the same time, allowing interactive discussion and adjusted benefit-risk weighing of each product on a case-by-case basis, e.g. for a unique treatment of a life threatening disease acceptable treatment risks may differ considerably from the ones in case of less serious disease. This theme was the focus of the international conference "Taking immunogenicity assessment of therapeutic proteins to the next level", held at the Paul-Ehrlich-Institut in Langen, Germany, on the 10-11. June 2010. The objectives of the conference were to highlight how the field could move from that of a mere description of risk factors to a system of risk assessment and mitigation, as well as an understanding of the impact of unwanted immunogenicity on the overall benefit/risk consideration for a medicinal product. More than 150 experts from industry, academia and regulatory authorities worldwide discussed the phenomenon of undesired immunogenicity from different perspectives. The conference focussed on issues relevant to three areas: (1) new European guidelines that are currently the subject of discussion; (2) testing strategies for immunogenicity assessment; and (3) scientific progress on the product-related factors that may contribute to the development of pathogenesis of immunogenicity, in particular in the field of protein aggregation and post-translational modifications. This report provides an overview of issues, insights, and conclusions that were discussed and achieved during the meeting.

Totality of the evidence at work: The first U.S. biosimilar.

On March 6(th) 2015, the Food and Drug Administration (FDA) approved filgrastim-sndz (Zarxio) as the first biosimilar in the United States (US) for all indications of the reference product. Filgrastim-sndz is a biosimilar of Amgen's Neupogen and is mainly used to treat neutropenia in cancer patients receiving chemotherapy. This article presents a summary of the analytical and clinical studies submitted by Sandoz and describes how the information was integrated to provide the 'totality of the evidence' leading to the approval of the biosimilar.

General Scheme for Oxidative Quenching of a Copper Bis-Phenanthroline Photosensitizer for Light-Driven Hydrogen Production.

A new, general reaction scheme for photocatalytic hydrogen production is presented based on oxidative quenching of a homoleptic copper(I) bis-1,10-phenanthroline photosensitizer (PS) by 1-methyl-4-phenyl-pyridinium (MPP(+) ) as the electron relay and subsequent regeneration of the so formed copper(II) complex by a sacrificial electron donor. Electron transfer from the relay to various cobalt based water reduction catalysts and subsequent H2 production was shown to close the catalytic cycle. Transient absorption experiments unambiguously confirmed the proposed pathway, both the oxidative quenching and subsequent regeneration of oxidized PS. Photocatalytic test runs further confirmed the role of MPP(+) and up to 10 turnovers were achieved in the relay. The performance limiting factor of the system was shown to be the decomplexation of the copper PS. Quantum yields of the system were 0.03 for H2 production, but 0.6 for MPP(.) formation, clearly indicating that unproductive pathways still prevail.

Inhibition of HIV-1 infection in vitro by monoclonal antibodies to the complement receptor type 3 (CR3): an accessory role for CR3 during virus entry?

Adhesion molecules are known to contribute to infectivity of HIV-1. Here we tested whether the complement receptor type 3 (CR3, CD11b), an alpha(m)beta2 integrin, plays an accessory role in the infection process of HIV-1, because ICAM-1, a ligand of CR3, is present on the envelope of HIV-1. In addition, the viral transmembrane protein gp41 shares four regions of homology with the complement component C3, a further CR3 ligand. Infection of PBMCs with HIV-IIIB and primary isolates was partially inhibited by anti-CR3 antibodies. A peptide derived from the complement component C3, covering the CR3-binding site of C3 and sharing strong similarity to the immunosuppressive region of gp41, significantly reduced the HIV-1 titer in infection assays. Recombinant soluble gp41 (rsgp41) and the peptide covering the immunosuppressive domain of gp41 inhibited the rosetting of iC3b-coated sheep erythrocytes with U937 via complement receptors (CRs) with an efficiency comparable to monoclonal anti-CR antibodies. In addition, sub-populations of CD4 + and CD8 + T-cells isolated from HIV-infected individuals were found to upregulate CR3 as determined by FACS analysis and on the mRNA level. Since gp41 has been implicated in viral fusion, an interaction of its C3-homology region in gp41 or an interaction of ICAM on the surface of free virus with CRs might contribute to facilitate viral entry.

[Palliative treatment of advanced gastric cancer from surgical point of view]. / Palliative Behandlung des fortgeschrittenen Magenkarzinoms aus chirurgischer Sicht.

Data are available on two multicenter observational studies, the East German Gastric Cancer Study (EGGCS) '02 (surgical interventions only) and the German Gastric Cancer Study II (QCGC) from 2007 to 2009 (after inauguration of multimodal therapeutic concepts) with regard to palliative treatment of advanced gastric cancer. Through the first investigation period from January to December 2002 (EGGCS) overall 1139 patients with primary gastric cancer were registered and evaluated and then from 2007 to 2009 (QCGC) another 2897 patients were included. Comparing both time periods, there were no significant changes in the distribution of tumor sites and stages according to the Union Internationale Contre le Cancer (UICC) classification, in particular, there was no significant reduction of advanced tumor stages. From 2007 to 2009 in total 521 patients (18 %) received neoadjuvant therapy, 401 patients (13.9 %) out of the group with curative intention and 120 (4.1 %) out of the group of patients with palliative intention. The proportion of palliative patients who underwent chemotherapy (with neoadjuvant intention and/or postoperatively) was 32.5 % (n = 223). Thus, the rate of palliative treatment (rate of no R0 resection status 29.6 %, rate of patients who did not undergo surgical intervention at all 9.5 %) could be diminished from almost 40 % in 2002 to 24.5 % through the time period from 2007 to 2009. Taking all patients together (with curative and palliative intention) an increase of the 4-year survival probability from 40.0 % to 48.5 % was observed after inauguration of multimodal therapy. After a 5-year follow-up median survival time was 34 months during the investigation period from 2007 to 2009 considering all study subjects. Patients who had undergone palliative surgical interventions benefited from postoperative palliative chemotherapy; however, as expected this was of greater benefit to patients with resecting surgical interventions than those with non-resecting operations. Palliative tumor resection (even R2 resection status) should be part of a concept of multimodal palliative therapy in cases of acceptable perioperative risk.

Specific neurotrophin binding to leucine-rich motif peptides of TrkA and TrkB.

The extracellular domains of the TrkA and TrkB neurotrophin receptors contain defined structural modules such as immunoglobulin-like domains and leucine-rich motifs (LRMs) [Schneider and Schweiger, Oncogene 6 (1991) 1807-1811]. Recently, the second LRM of TrkA was identified as a functional nerve growth factor (NGF) binding site [Windisch et al, J. Biol. chem. (1995) in press]. A peptide corresponding to this region effectively bound NGF and blocked binding of NGF to the recombinant extracellular domain of TrkA. The corresponding TrkB peptide exhibited the same effects with respect to brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4 (NT-4), indicating that all three TrkB ligands utilize this same binding site. Isolated LRMs therefore embody independent functional entities.

Hyperandrogenism, postprandial hyperinsulinism and the risk of PCOS in a cross sectional study of women with epilepsy treated with valproate.

Among a sample of 43 women with epilepsy treated for at least 2 years with valproate (n=22) or other antiepileptic drugs (AEDs) (n=21), polycystic ovary syndrome (PCOS) was diagnosed in three women, two of them were treated with valproate. Although the rate of PCOS and of menstrual disturbances, weight body mass index (BMI) and waist to hip ratio as well as fasting blood glucose levels, fasting insulin, proinsulin and C-peptide values was similar in this small sample of women treated with valproate and other AEDs, valproate exposure was associated with higher androgen levels, higher postprandial (pp) insulin and proinsulin levels, as well as lower cholesterol and low density lipoprotein (LDL) cholesterol levels. The pronounced increase in pp insulin levels during VPA treatment may indicate an effect of the fatty acid derivate VPA on pancreatic islet cells.

Nerve growth factor binding site on TrkA mapped to a single 24-amino acid leucine-rich motif.

The extracellular domains of the TrkA nerve growth factor (NGF) receptor and its homologs harbor a modular mosaic of potential ligand binding motifs, namely two immunoglobulin (Ig)-like modules and an LRM3 cassette consisting of a tandem array of three leucine-rich motifs (LRMs) flanked by cysteine-rich clusters (Schneider, R., and Schweiger, M. (1991) Oncogene 6, 1807-1811). Identification of a structural motif capable of specifically recognizing the various neurotrophins was achieved by assessing their affinities to isolated recombinant modules of TrkA and TrkB. In both receptors the LRM3 cassette alone could mediate the respective neurotrophin selectivities and affinities. Further tracking down of this NGF-binding site in TrkA strikingly revealed that a single LRM of 24 amino acids could bind NGF selectively with nanomolar affinity. Since this is the first example of a single LRM with a highly specific, well defined function, it might serve as a valuable tool to elucidate the general structural requirements of substrate recognition and high affinity binding in the large superfamily of LRM-containing proteins.

RNase of classical swine fever virus: biochemical characterization and inhibition by virus-neutralizing monoclonal antibodies.

The structural glycoprotein E0 of classical swine fever virus (CSFV) possesses an intrinsic RNase activity. Here we present the first comprehensive biochemical characterization of E0, using a recombinant glycoprotein expressed in insect cells. We were able to show that the presence of neither carbohydrate moieties nor disulfide bonds is a prerequisite for RNase activity. In addition, virus-neutralizing and nonneutralizing anti-E0 monoclonal antibodies were tested for their ability to influence RNase activity. In these experiments, the antibodies which effectively blocked the infection of STE cells also exerted a high degree of E0 RNase inhibition. This correlation suggests that the RNase activity of CSFV E0 plays a role in the viral life cycle.

Brain-derived neurotrophic factor, neurotrophin-3, and neurotrophin-4 bind to a single leucine-rich motif of TrkB.

TrkB is a member of the Trk family of neurotrophin receptors. Its extracellular domain exhibits the same modular structure found in its homologs, TrkA and TrkC, consisting of an N-terminal LRM3 cassette and two immunoglobulin-like modules (Ig2 domain) adjacent to the membrane. The LRM3 cassette comprises two cysteine-rich clusters framing a tandem array of three leucine-rich motifs (LRMs). On the basis of the recent identification of a nerve growth factor (NGF) binding site within TrkA, the ability of the different structural entities within the extracellular domain of TrkB to bind the various neurotrophins was determined by using a recombinant receptor approach. Brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4 (NT-4) bound to the LRM3 cassette of TrkB, whereas NGF did not. These binding characteristics evidently reflect in vivo specificities. A more precise mapping of the region(s) responsible for binding BDNF, NT-3, and NT-4 identified the second leucine-rich motif of TrkB as a functional unit capable of binding all three neurotrophins. The affinities and kinetics that this short stretch of amino acids exhibited with respect to the different neurotrophins were clearly akin to those observed for cells ectopically expressing TrkB receptors. With 24 amino acids determining the affinities and kinetics of the interactions with three different partners, the leucine-rich motif is strongly established as one of the most potent and flexible protein--protein interaction motifs.

Cell death of adult pyramidal CA1 neurons after intraventricular injection of a novel peptide derived from trkA.

Members of the nerve growth factor (NGF) family of neurotrophins bind to the second leucine-rich motif (LRM2) within the extracellular domains of their respective receptors (trkA, trkB, trkC). Small LRM2 peptides have been recently demonstrated to selectively bind the neurotrophins revealing similar complex binding characteristics as full-length receptors. We extend our recent findings, showing that the peptides (A and C) do not block nerve fiber outgrowth through high affinity trk receptors in a ganglia bioassay. Since the highest concentration of neurotrophins [NGF, brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3)] is found in the hippocampus, the peptides were injected into the 3rd ventricle of anesthetized adult rats. The (NGF binding) LRM2-A peptide, but not the (BDNF binding) LRM2-B or the (NT-3 binding) LRM2-C peptides, caused severe apoptotic neurodegeneration of hippocampal pyramidal CA1 neurons as revealed by cresyl violet staining and the TUNEL reaction. The degeneration was protected by intrahippocampal injection of NGF-beta and by the non-N-methyl-D-aspartate (NMDA) antagonist CNQX (6-cyano-7-nitroquinoxaline-2,3-dione), indicating a glutamatergic mechanism. In situ hybridization revealed that pyramidal CA1 neurons did not express trkA and p75 receptor mRNA in sham and LRM2-A-lesioned animals. It is concluded that the LRM2-A peptide represents a novel peptide with properties to induce apoptotic cell death of pyramidal CA1 neurons and may be useful as an experimental agent.