XL-protein GmbH

What XL-protein GmbH does

XL-protein GmbH is a privately held German biopharmaceutical company founded in 2009 and headquartered in Freising, near Munich. The company develops and licenses PASylation, a proprietary half-life extension technology that uses genetic fusion or chemical coupling of unstructured, biodegradable PAS (Proline-Alanine-Serine) polypeptide sequences to therapeutic proteins, peptides, cytokines, enzymes, and antibody fragments. Unlike PEGylation, PAS sequences are genetically encodable, produced in microbial or cell-culture hosts, and biodegrade without organ accumulation. Across multiple animal studies the technology has demonstrated 10-100 fold plasma half-life extension while preserving bioactivity.

The company's commercial offering rests on three pillars: (1) the PASylation technology platform itself, which is out-licensed to pharmaceutical and biotech partners on a territory- and indication-specific basis in exchange for upfront payments, development and regulatory milestones, and royalties on net sales; (2) research reagents sold directly via the XL-protein online shop, including the PAS(200) polymer (EUR 800-8,600 per unit) and the Avi-PA(S)-MAb1.1 detection antibody (EUR 450-3,250 per unit); and (3) collaborative research and feasibility studies with manufacturing partners such as Wacker Biotech (ESETEC E. coli system) and Ajinomoto Bio-Pharma Services (Corynex expression system), which have produced PASylated proteins at industrial yields of 3-4 g/L.

XL-protein's customer base is concentrated among global pharma and biotech companies developing long-acting biologics. Named licensees and collaborators include Jazz Pharmaceuticals (asparaginase for ALL), Akari Therapeutics (Coversin and PAS-nomacopan for complement-mediated disease and geographic atrophy), AdAlta (AD-114 for idiopathic pulmonary fibrosis), MSD Animal Health (veterinary biologics), Grifols (worldwide license granted June 2025), GENERIUM (Russia/CIS), Easton Pharmaceutical (China, ophthalmology), Horizon Pharma (gout), DNX Biopharmaceuticals, Phylogica, and Yeda Research and Development. The company is led by CEO/CFO Claus Schalper with founder Prof. Dr. Arne Skerra serving as CSO/Chairman; the team comprises 1-10 employees. In May 2026, XL-protein launched spin-off PASylANTA Therapeutics to develop long-acting IL-1Ra biobetters.

Name

XL-protein GmbH

Legal name

XL-protein GmbH

Website

https://xl-protein.com

Company type

Private

Founded year

2009

Operating status

Operating

Headcount range

1–10 employees

Short description

XL-protein GmbH is a privately held German biopharmaceutical company that licenses proprietary PASylation technology, a biological alternative to PEGylation extending plasma half-life of therapeutic proteins, to pharma and biotech partners worldwide and sells related research reagents online.

Ownership category

akta.pro rank

Product category

Biopharmaceutical technology licensing

NAICS

Research and Development in Biotechnology (except Nanobiotechnology) (541714)

SIC

Biological Products, (No Disgnostic Substances) (2836)

akta.pro primary industry

Protein Engineering & Directed Evolution Platforms (enzyme/therapeutic protein optimization) (HLAAAIAC)

akta.pro secondary industries

Engineered Protein Therapeutics (de novo/AI-designed proteins, novel scaffolds) (HLAAAAAJ), Therapeutic Peptides & Protein/Peptide Biologics (HLAAAAAH)

Keywords

• Protein half-life extension
• PASylation technology platform
• Biopharmaceutical licensing
• PEGylation alternative polymers
• Biobetter drug development

Headquarters

HQ city

Freising

HQ country

Germany

HQ region

Europe

Offices1 record

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Technology or R&D, Operations, Supply Chain, Marketing or Sales

Revenue model

1. Licensing Royalties: XL-protein licenses its PASylation technology to pharmaceutical and biotech partners in exchange for upfront payments, preclinical/clinical/regulatory/commercial milestone payments, and royalties on net sales of resulting products. Licensing covers specific therapeutic areas and geographies.
2. Research Product Sales: Sale of research reagents including PAS(200) polymer (1-10 mg) and Avi-PA(S)-MAb1.1 antibody (100 µg to 1 mg) through the XL-protein online shop, targeted at commercial customers and academic research labs. Prices range from 450 EUR to 8,600 EUR per unit.
3. Research Collaborations and Feasibility Studies: Collaborative research agreements with partners such as Wacker Biotech, DNX, and Ajinomoto to demonstrate feasibility of producing PASylated proteins using partner expression platforms (ESETEC, Corynex). Revenue from service and support activities.

Pricing tiers

Go-to-market motion1 record

Distribution channels2 records

Marketing channels4 records

Core offering

XL-protein GmbH develops and licenses the proprietary PASylation technology, a biological half-life extension platform that uses unstructured, biodegradable PAS (Proline-Alanine-Serine) polypeptide sequences fused or coupled to therapeutic proteins and peptides. The company monetizes the platform through exclusive, territory- or indication-specific licensing deals with pharma/biotech partners, plus direct online sales of research reagents (PAS(200) polymer and Avi-PA(S)-MAb1.1 antibody) to academic and commercial research labs.

Product overview

XL-protein GmbH offers a proprietary PASylation® technology platform that serves as a biological alternative to PEGylation for extending the plasma half-life of biopharmaceuticals. The company commercializes this technology through two main research products sold via its online shop: the Avi-PA(S)®-MAb1.1 antibody for PAS detection and pharmacokinetic analysis, and PAS(200) polymer reagents for half-life extension. XL-protein also pursues preclinical and clinical development of PASylated proteins in various disease areas and offers licensing opportunities to pharmaceutical and biotech partners.

Differentiator

Problem solved

Functional benefit

Products and services

• PAS(200) polymer Biodegradable PEG alternative polypeptide of 201 amino acids (Proline, Alanine, Serine) designed to expand the hydrodynamic volume of drugs and extend plasma half-life; available as unmodified, Pga-PAS(200), or iodoacetyl-functionalized forms for chemical coupling to biomolecules containing free thiols. Sold for research use only via the XL-protein online shop at EUR 800–8,600 per unit.
• Avi-PA(S)-MAb1.1 antibody Recombinant mouse IgG1/kappa monoclonal antibody that recognizes the Proline/Alanine-rich PA(S)#1 repetitive sequence, used for sensitive PAS detection and pharmacokinetic analysis of PASylated proteins. Suitable for ELISA, SPR, and Western Blotting. Expressed in HEK cells. Sold at EUR 450–3,250 per unit for research use only.
• PASylation Technology Platform Licensing Exclusive, territory- or indication-specific licensing of the proprietary PASylation half-life extension technology to pharmaceutical, biotechnology, and animal health partners, granting rights to develop, manufacture, and commercialize PASylated products in exchange for upfront payments, milestone payments, and royalties on net sales.
• Research collaborations and feasibility studies Collaborative feasibility studies and process development using partner expression platforms (ESETEC, Corynex) to demonstrate high-yield production of PASylated proteins, generating service revenue and supporting licensing diligence.

Quantifiable outcome

• Plasma half-life extended by factor of 10-100 across various therapeutic proteins in animal studies
• +4 more outcomes

Named customers12 records

Segments3 records

Ideal customer profiles3 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature3 records

Partnerships

17 partnerships are on record, tiered major, core and minor.

• PASylANTA Therapeutics (Spin-off)majorStrategic or Co-development Partner · 28 May 2026XL-protein launched spin-off company PASylANTA Therapeutics to develop long-acting IL-1Ra biobetters. This represents an internal pipeline development spin-off leveraging the PASylation platform.
• GrifolsmajorOEM/ Whitelabel/ Licensing Partner · 10 June 2025XL-protein granted worldwide license to Grifols to develop a biopharmaceutical using PASylation technology. Announcement made June 2025.
• Ajinomoto Bio-Pharma ServicescoreStrategic or Co-development Partner · 18 December 2018Strategic alliance combining Ajinomoto's Corynex expression system with XL-protein's PASylation technology. Produced PASylated GLP-1 variant at >3 g/l yield with drastically prolonged half-life in mice, suggesting weekly or biweekly human dosing. Ajinomoto started partnering process for the molecule.
• Horizon Pharma plcminorStrategic or Co-development Partner · 7 January 2018Collaboration agreement to identify clinical-stage program candidates using PASylation technology to construct a next-generation gout biologic based on uricase, with potential for extended half-life and subcutaneous dosing.
• Jazz Pharmaceuticals plcmajorOEM/ Whitelabel/ Licensing Partner · 26 July 2017License agreement for rights to develop, manufacture and commercialize PASylated asparaginase product candidates for acute lymphoblastic leukemia (ALL). Jazz paid USD 2 million upfront plus milestone and royalty payments. PASylation intended to extend circulating half-life and duration of therapeutic effect.
• AdAlta LimitedmajorOEM/ Whitelabel/ Licensing Partner · 7 November 2016Research and evaluation collaboration to apply PASylation to AD-114, AdAlta's lead i-body anti-fibrotic drug candidate for Idiopathic Pulmonary Fibrosis (IPF). Pilot studies in animal models showed dramatically extended plasma half-life. Subsequently upgraded to commercial license in November 2017.
• Akari Therapeutics PlcmajorOEM/ Whitelabel/ Licensing Partner · 14 April 2016License agreement to develop PASylated version of Coversin (a complement C5 inhibitor) for Paroxysmal Nocturnal Hemoglobinuria, atypical Hemolytic Uremic Syndrome, and Guillain Barré syndrome. Preclinical study showed 50-fold plasma half-life extension. XL-protein received upfront and milestone payments plus royalties.
• Easton Pharmaceutical Co., Ltd.majorOEM/ Whitelabel/ Licensing Partner · 17 December 2015License, development and commercialization agreement for novel long-acting PASylated biopharmaceuticals for ophthalmology and other indications for China. XL-protein receives upfront, milestone payments and tiered mid-single digit royalties on sales. Easton has exclusive China marketing rights with options for worldwide rights.
• DNX Biopharmaceuticals, Inc.majorStrategic or Co-development Partner · 30 June 2015Collaboration for development and commercialization of novel long-acting biopharmaceutical products. XL-protein contributes PASylation technology and molecules with completed in vivo proof-of-concept; DNX contributes pipeline candidates for Immunology, Metabolism and Ophthalmology. Financial terms undisclosed.
• MSD Animal HealthmajorOEM/ Whitelabel/ Licensing Partner · 12 February 2015Worldwide exclusive license for certain biopharmaceutical drug candidates using PASylation technology for animal health applications. Followed research collaboration initiated in 2012 including feasibility study in target animals. MSD Animal Health responsible for clinical development and commercialization.
• Yeda Research and Development Company Ltd. (Weizmann Institute of Science)majorStrategic or Co-development Partner · 21 October 2014Business collaboration agreement to commercialize PAS-YNSα8, a PASylated interferon superagonist jointly developed with Weizmann Institute scientists. YEDA acquired worldwide exclusive rights for marketing and out-licensing. PAS-YNSα8 showed 10-fold half-life increase and superior efficacy in MS mouse model. Published in Journal of Biological Chemistry (2014).
• Scientific Journals (Protein Engineering Design & Selection; BioProcess International)minorOthers · 30 August 2013Key scientific data on PASylation technology published in peer-reviewed Open Access journal (Protein Engineering, Design & Selection, Vol. 26, No. 8, pp. 489–501) and BioProcess International (Vol. 11, No. 4, pp. 30–38) validating the technology platform.
• GENERIUMmajorStrategic or Co-development Partner · 25 June 2013License and collaboration agreement for development of PASylated blood clotting factor and cytokine for Russian Federation and Commonwealth of Independent States (CIS). XL-protein received seven-digit USD upfront payment plus preclinical/clinical/regulatory/commercial milestones and royalties. GENERIUM has exclusive marketing rights in Russia/CIS; XL-protein retains Rest of World rights.
• Wacker Biotech GmbHcoreStrategic or Co-development Partner · 30 October 2012Long-term cooperation agreement signed following successful feasibility study. Wacker Biotech and XL-protein offer pharmaceutical customers access to the combined PASylation platform and ESETEC technology for production of PASylated biopharmaceuticals. Wacker Biotech provides GMP-compliant manufacturing capability.
• Wacker Biotech GmbHcoreTechnology or Integration · 11 June 2012Successful feasibility study demonstrated high-yield production (3-4 g/l) of PASylated human growth hormone using WACKER's ESETEC E. coli secretion technology. The study confirmed that PASylated proteins can be correctly folded, secreted into culture medium, and efficiently purified.
• Phylogica LtdminorStrategic or Co-development Partner · 13 January 2011Collaboration to validate PASylation technology in combination with Phylogica's Phylomer peptides targeting CD40 ligand from its anti-inflammatory program. Phylogica obtained an option for exclusive license for PASylation with CD40 ligand targets and rights of negotiation for other Phylomer targets.
• Technical University of Munich (TUM)coreTechnology or Integration · 17 September 2009XL-protein entered into an exclusive worldwide licensing agreement with TUM via the Bavarian Patent Alliance GmbH for the PASylation technology originally developed at the Institute of Biological Chemistry at TUM. This agreement gave XL-protein exclusive rights including sublicensing rights to the foundational PASylation IP.

Scale indicators8 records

Recent moves8 records

Expansion highlights5 records

Direct peers

• Ascendis Pharma: Ascendis Pharma's TransCon platform is a prodrug-based half-life extension technology licensed to multiple pharma partners for long-acting biologics. Closely comparable to XL-protein's PASylation platform in business model (B2B technology licensing to pharma) and therapeutic goal (less frequent dosing).
• Halozyme Therapeutics: Halozyme's ENHANZE platform licenses recombinant hyaluronidase to pharma partners (e.g., Roche, Janssen, Pfizer) to enable subcutaneous delivery of biologics. Highly comparable licensing/platform model to XL-protein, though ENHANZE focuses on delivery rather than half-life extension per se.
• Nektar Therapeutics: Nektar pioneered PEGylation-based half-life extension for biologics and licenses its polymer conjugation technology to pharma partners. The most direct historical competitor to PASylation and the established incumbent XL-protein is positioning against.
• Xencor: Xencor's XmAb protein engineering platform generates Fc-engineered and bispecific antibodies licensed to pharma partners. Comparable in that Xencor is a protein-engineering platform monetized via licensing, though focused on antibody engineering rather than half-life extension.
• CytomX Therapeutics: CytomX's Probody platform licenses conditionally activated antibody technology to pharma partners (e.g., Astellas, BMS). Comparable B2B protein-engineering platform licensing model with similar capital-light partner-driven development.
• Molecular Partners: Molecular Partners develops DARPin protein scaffolds licensed to pharma (e.g., Novartis for abicipar) for therapeutic applications. Similar small-platform protein-engineering licensing model with pharma partners across multiple therapeutic areas.
• AdAlta: AdAlta (ASX: ADT) is both a peer and an actual XL-protein partner; it licenses PASylation for its i-body AD-114 fibrosis program. As a small Australian biologics developer with a similar licensing-driven growth profile, it is a directly comparable business in structure and scale.

Emerging players

• Genexine: Genexine's hyFc (hybrid Fc) technology fuses IgD/IgG4 for half-life extension of therapeutic proteins, with multiple partnered programs in clinical development. Closely comparable technical approach to PASylation (protein-based half-life extension alternative to PEGylation).
• Prolong Pharmaceuticals: Prolong Pharmaceuticals develops PEG-based and protein-based half-life extension technologies for plasma proteins and biologics. Comparable small-cap protein-engineering company focused on half-life extension in similar therapeutic areas.

Broad incumbents

• Ablynx (part of Sanofi): Sanofi's Ablynx unit commercializes Nanobody single-domain antibody platforms and was acquired for its technology licensing model. Comparable historical model of a small protein-engineering platform that scaled via licensing to large pharma.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks6 records

Key highlights7 records

Customer concentration

• LinkedInlinkedin.com/company/xl-protein

Revenue estimate

Valuation estimate

Number of profiles

Profiles3 records

Funding overview

Funding rounds

Investors

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M&A

Investments

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Frequently asked questions about XL-protein GmbH