XL protein GmbH

Freising, Germany

XL protein GmbH

Freising, Germany
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Binder U.,XL protein GmbH | Skerra A.,XL protein GmbH
Pharmazeutische Industrie | Year: 2015

Rapid clearance from blood circulation by renal filtration is a typical drawback of most therapeutic proteins and peptides (except for full size antibodies), in particular established biologics such as hormones, growth factors, cytokines and enzymes, but also immunoglobulin fragments (Fab, scFv or single domain/nanobody). Chemical conjugation with poly-ethylene glycol (PEG), which expands the effective molecular size beyond the threshold of kidney filtration, is a well known strategy to prolong the short plasma half-life of biopharmaceuticals to a clinically useful range. However, coupling with the synthetic polymer PEG requires expensive material and additional downstream procedures and, furthermore, PEG can accumulate in organs due to its lack of biodegradability. An alternative is the use of conformationally disordered polypeptide chains with large hydrodynamic volume comprising the small amino acid residues proline, alanine, and/or serine (PAS). PAS sequences are hydrophilic, uncharged biological polymers with biophysical properties surprisingly similar to PEG. In contrast, PAS polypeptides offer fusion to a biological drug on the genetic level, permitting facile production of fully active proteins in E. coli or in eukaryotic cell culture and obviating in vitro coupling or modification steps. Also, PAS polymers are biodegradable, thus avoiding tissue accumulation, while showing stability in plasma and lacking toxicity or immunogenicity in animals. Hence, PASylation® provides a modular technology to design superior novel biologics or so-called biobetters. © ECV -Editio Cantor Verlag, Aulendorf (Germany).


Binder U.,XL protein GmbH | Skerra A.,TU Munich
Current Opinion in Colloid and Interface Science | Year: 2017

PASylation® technology comprises the conjugation – via genetic fusion or chemical coupling – of pharmacologically active compounds, such as proteins, peptides and low molecular weight drugs, with natively disordered biosynthetic polymers made of the small L-amino acids Pro, Ala and/or Ser. Such proline/alanine-rich sequences (PAS) are highly soluble in physiological solution and stably adopt random coil conformation, which results in an expanded hydrodynamic volume. Consequently, PAS-drug conjugates show retarded kidney filtration and drastically prolonged pharmacokinetics (PK) in vivo. The intrinsically uncharged PAS polypeptides do not interfere with the pharmacological activity of the drug component and show high stability in plasma as well as no immunogenicity, while undergoing quick degradation and metabolization after cellular uptake. PASylation has been successfully applied to a wide range of pharmacologically active proteins and peptides, including hormones, cytokines, antibody fragments and enzymes, as well as nanocarriers. This review discusses the fundamental concepts of PASylation technology and recent advances in preclinical applications. © 2017 Elsevier Ltd


Morath V.,TU Munich | Bolze F.,TU Munich | Schlapschy M.,TU Munich | Schneider S.,TU Munich | And 5 more authors.
Molecular Pharmaceutics | Year: 2015

Leptin plays a central role in the control of energy homeostasis and appetite and, thus, has attracted attention for therapeutic approaches in spite of its limited pharmacological activity owing to the very short circulation in the body. To improve drug delivery and prolong plasma half-life, we have fused murine leptin with Pro/Ala/Ser (PAS) polypeptides of up to 600 residues, which adopt random coil conformation with expanded hydrodynamic volume in solution and, consequently, retard kidney filtration in a similar manner as polyethylene glycol (PEG). Relative to unmodified leptin, size exclusion chromatography and dynamic light scattering revealed an approximately 21-fold increase in apparent size and a much larger molecular diameter of around 18 nm for PAS(600)-leptin. High receptor-binding activity for all PASylated leptin versions was confirmed in BIAcore measurements and cell-based dual-luciferase assays. Pharmacokinetic studies in mice revealed a much extended plasma half-life after ip injection, from 26 min for the unmodified leptin to 19.6 h for the PAS(600) fusion. In vivo activity was investigated after single ip injection of equimolar doses of each leptin version. Strongly increased and prolonged hypothalamic STAT3 phosphorylation was detected for PAS(600)-leptin. Also, a reduction in daily food intake by up to 60% as well as loss in body weight of >10% lasting for >5 days was observed, whereas unmodified leptin was merely effective for 1 day. Notably, application of a PASylated superactive mouse leptin antagonist (SMLA) led to the opposite effects. Thus, PASylated leptin not only provides a promising reagent to study its physiological role in vivo but also may offer a superior drug candidate for clinical therapy. © 2015 American Chemical Society.


Breibeck J.,TU Munich | Serafin A.,TU Munich | Reichert A.,TU Munich | Maier S.,TU Munich | And 3 more authors.
Journal of the American Society for Mass Spectrometry | Year: 2014

We describe the design, preparation, and mass-spectrometric characterization of a new recombinant peptide calibration standard with uniform biophysical and ionization characteristics for mass spectrometry. "PAS-cal" is an artificial polypeptide concatamer of peptide cassettes with varying lengths, each composed of the three small, chemically stable amino acids Pro, Ala, and Ser, which are interspersed by Arg residues to allow site-specific cleavage with trypsin. PAS-cal is expressed at high yields in Escherichia coli as a Small Ubiquitin-like MOdifier (SUMO) fusion protein, which is easily purified and allows isolation of the PAS-cal moiety after SUMO protease cleavage. Upon subsequent in situ treatment with trypsin, the PAS-cal polypeptide yields a set of four defined homogeneous peptides in the range from 2 to 8 kDa with equal mass spacing. ESI-MS analysis revealed a conveniently interpretable raw spectrum, which after deconvolution resulted in a very simple pattern of four peaks with similar ionization signals. MALDI-MS analysis of a PAS-cal peptide mixture comprising both the intact polypeptide and its tryptic fragments revealed not only the four standard peptides but also the singly and doubly charged states of the intact concatamer as well as di- and trimeric adduct ion species between the peptides, thus augmenting the observable m/z range. The advantageous properties of PAS-cal are most likely a result of the strongly hydrophilic and conformationally disordered PEG-like properties of the PAS sequences. Therefore, PAS-cal offers an inexpensive and versatile recombinant peptide calibration standard for mass spectrometry in protein/peptide bioanalytics and proteomics research, the composition of which may be further adapted to fit individual needs.


Mendler C.T.,TU Munich | Friedrich L.,TU Munich | Laitinen I.,TU Munich | Schlapschy M.,TU Munich | And 4 more authors.
mAbs | Year: 2015

Although antigen-binding fragments (Fabs) of antibodies constitute established tracers for in vivo radiodiagnostics, their functionality is hampered by a very short circulation half-life. PASylation, the genetic fusion with a long, conformationally disordered amino acid chain comprising Pro, Ala and Ser, provides a convenient way to expand protein size and, consequently, retard renal filtration. Humanized αHER2 and αCD20 Fabs were systematically fused with 100 to 600 PAS residues and produced in E. coli. Cytofluorimetric titration analysis on tumor cell lines confirmed that antigen-binding activities of the parental antibodies were retained. The radio-iodinated PASylated Fabs were studied by positron emission tomography (PET) imaging and biodistribution analysis in mouse tumor xenograft models. While the unmodified aHER2 and αCD20 Fabs showed weak tumor uptake (0.8% and 0.2% ID/g, respectively; 24 h p.i.) tumor-associated radioactivity was boosted with increasing PAS length (up to 9 and 26-fold, respectively), approaching an optimum for Fab-PAS400. Remarkably, 6- and 5-fold higher tumor-to-blood ratios compared with the unmodified Fabs were measured in the biodistribution analysis (48 h p.i.) for aHER2 Fab-PAS100 and Fab-PAS200, respectively. These findings were confirmed by PET studies, showing high imaging contrast in line with tumor-to-blood ratios of 12.2 and 5.7 (24 h p.i.) for aHER2 Fab-PAS100 and Fab-PAS200. Even stronger tumor signals were obtained with the corresponding αCD20 Fabs, both in PET imaging and biodistribution analysis, with an uptake of 2.8% ID/g for Fab-PAS100 vs. 0.24% ID/ g for the unmodified Fab. Hence, by engineering Fabs via PASylation, plasma half-life can be tailored to significantly improve tracer uptake and tumor contrast, thus optimally matching reagent/target interactions. © 2015 Taylor & Francis Group, LLC.


Kuhn N.,TU Munich | Schmidt C.Q.,University of Ulm | Schlapschy M.,TU Munich | Schlapschy M.,XL protein GmbH | And 2 more authors.
Bioconjugate Chemistry | Year: 2016

The Ornithodoros moubata Complement Inhibitor (OmCI) binds complement component 5 (C5) with high affinity and, thus, selectively prevents proteolytic activation of the terminal lytic complement pathway. A recombinant version of OmCI (also known as Coversin and rEV576) has proven efficacious in several animal models of complement-mediated diseases and successfully completed a phase Ia clinical trial. Coversin is a small 17 kDa lipocalin protein which has a very short plasma half-life if not bound to C5; therefore, the drug requires frequent dosing. We have improved the pharmacokinetics of Coversin by N-terminal translational conjugation with a 600 residue polypeptide composed of Pro, Ala, and Ser (PAS) residues. To this end, PAS-Coversin as well as the unmodified Coversin were functionally expressed in the cytoplasm of E. coli and purified to homogeneity. Both versions showed identical affinity to human C5, as determined by surface plasmon resonance measurements, and revealed similar complement inhibitory activity, as measured in ELISAs with human serum. In line with the PEG-like biophysical properties, PASylation dramatically prolonged the plasma half-life of uncomplexed Coversin by a factor ≥50 in mice. In a clinically relevant in vitro model of the complement-mediated disease paroxysmal nocturnal hemoglobinuria (PNH) both versions of Coversin effectively reduced erythrocyte lysis. Unexpectedly, while the IC50 values were comparable, PAS-Coversin reached a substantially lower plateau of residual lysis at saturating inhibitor concentrations. Taken together, our data demonstrate two clinically relevant improvements of PASylated Coversin: markedly increased plasma half-life and considerably reduced background hemolysis of erythrocytes with PNH-induced phenotype. © 2016 American Chemical Society.


Schlapschy M.,TU Munich | Binder U.,XL protein GmbH | Borger C.,TU Munich | Theobald I.,TU Munich | And 5 more authors.
Protein Engineering, Design and Selection | Year: 2013

A major limitation of biopharmaceutical proteins is their fast clearance from circulation via kidney filtration, which strongly hampers efficacy both in animal studies and in human therapy. We have developed conformationally disordered polypeptide chains with expanded hydrodynamic volume comprising the small residues Pro, Ala and Ser (PAS). PAS sequences are hydrophilic, uncharged biological polymers with biophysical properties very similar to poly-ethylene glycol (PEG), whose chemical conjugation to drugs is an established method for plasma half-life extension. In contrast, PAS polypeptides offer fusion to a therapeutic protein on the genetic level, permitting Escherichia coli production of fully active proteins and obviating in vitro coupling or modification steps. Furthermore, they are biodegradable, thus avoiding organ accumulation, while showing stability in serum and lacking toxicity or immunogenicity in mice. We demonstrate that PASylation bestows typical biologics, such as interferon, growth hormone or Fab fragments, with considerably prolonged circulation and boosts bioactivity in vivo. © 2013 © The Author 2013. Published by Oxford University Press.


Bolze F.,TU Munich | Morath V.,TU Munich | Bast A.,TU Munich | Rink N.,TU Munich | And 5 more authors.
Endocrinology | Year: 2016

Body weight loss of Lepob/ob mice in response to leptin is larger than expected from the reduction in energy intake alone, suggesting a thermogenic action ofunknownmagnitude.Weexploited the superior pharmacological properties of a novel long-acting leptin prepared via PASylation to study the contribution of its anorexigenic and thermogenic effects. PASylation, the genetic fusion of leptin with a conformationally disordered polypeptide comprising 600 Pro/Ala/Ser (PAS) residues, provides a superior way to increase the hydrodynamic volume of the fusion protein, thus retarding kidney filtration and extending plasma half-life. Here a single PAS(600)-leptin injection (300 pmol/g) resulted in a maximal weight reduction of 21% 6 days after application. The negative energy balance of 300 kJ/(4 d) was driven by a decrease in energy intake, whereas energy expenditure remained stable. Mice that were food restricted to the same extent showed an energy deficit of only 220 kJ/(4 d)owingto recurring torpor bouts. Therefore, the anorexigenic effect of PAS(600)-leptin contributes 75% to weight loss, whereas the thermogenic action accounts for 25% by preventing hypometabolism. In a second experiment, just four injections of PAS(600)-leptin (100 pmol/g) administered in 5- to 6-day intervals rectified the Lepob/ob phenotype. In total, 16 nmol of PAS(600)-leptin per mouse triggered a weight loss of 43% within 20 days and normalized hypothermia and glucose homeostasis as well as hepatic steatosis. The beneficial properties of PAS(600)-leptin are substantiated by a comparison with previous studies in which approximately 400 nmol (∼25-fold) unmodified leptin was mandatory to achieve similar improvements. Copyright © 2016 by the Endocrine Society.


Patent
TU Munich and Xl Protein Gmbh | Date: 2015-11-12

The present invention relates to a biosynthetic random coil polypeptide or a biosynthetic random coil polypeptide segment or biosynthetic conjugate, wherein said biosynthetic random coil polypeptide, said biosynthetic random coil polypeptide segment or said biosynthetic conjugate comprises an amino acid sequence consisting solely of proline and alanine amino acid residues, wherein said amino acid sequence consists of at least about 50 proline (Pro) and alanine (Ala) amino acid residues. Said at least about 50 proline (Pro) and alanine (Ala) amino acid residues may be (a) constituents) of a heterologous polypeptide or an heterologous polypeptide construct. Also uses and methods of use of these biosynthetic random coil polypeptides or polypeptide segments or said conjugates are described.


PubMed | XL protein GmbH
Type: Journal Article | Journal: Molecular pharmaceutics | Year: 2015

Leptin plays a central role in the control of energy homeostasis and appetite and, thus, has attracted attention for therapeutic approaches in spite of its limited pharmacological activity owing to the very short circulation in the body. To improve drug delivery and prolong plasma half-life, we have fused murine leptin with Pro/Ala/Ser (PAS) polypeptides of up to 600 residues, which adopt random coil conformation with expanded hydrodynamic volume in solution and, consequently, retard kidney filtration in a similar manner as polyethylene glycol (PEG). Relative to unmodified leptin, size exclusion chromatography and dynamic light scattering revealed an approximately 21-fold increase in apparent size and a much larger molecular diameter of around 18 nm for PAS(600)-leptin. High receptor-binding activity for all PASylated leptin versions was confirmed in BIAcore measurements and cell-based dual-luciferase assays. Pharmacokinetic studies in mice revealed a much extended plasma half-life after ip injection, from 26 min for the unmodified leptin to 19.6 h for the PAS(600) fusion. In vivo activity was investigated after single ip injection of equimolar doses of each leptin version. Strongly increased and prolonged hypothalamic STAT3 phosphorylation was detected for PAS(600)-leptin. Also, a reduction in daily food intake by up to 60% as well as loss in body weight of >10% lasting for >5 days was observed, whereas unmodified leptin was merely effective for 1 day. Notably, application of a PASylated superactive mouse leptin antagonist (SMLA) led to the opposite effects. Thus, PASylated leptin not only provides a promising reagent to study its physiological role in vivo but also may offer a superior drug candidate for clinical therapy.

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