Ideas thrive better under professional protection.

Dr. Andreas Oser

Dr. rer. nat., Dipl.-Chem.
German Patent Attorney, European Patent Attorney,
European Trademark and Design Attorney
Master of Laws

+49 89 69 39 21-0oser@pruefer.eu

Professional career

Andreas Oser has been working in the IP field since 1991, became a German and European patent attorney in 1995 and has been managing partner at Prüfer & Partner since 2002.
In addition he holds an LL.M. degree in International Intellectual Property Laws (University of Hagen).
Prior to working in the IP field, he studied chemistry at the University of Freiburg i. Brsg., and then completed his Ph.D. and postdoctorate scientific work at the Max Planck Institute for Biochemistry in Munich.

German, English, French

Specialist areas of activity


  • Patent prosecution (drafting, examination)
  • High number of opposition and appeal proceedings at the European Patent Office
  • Patent litigation:
    • Patent infringement proceedings before German courts
    • nullity proceedings up to the highest instance, the Federal Supreme Court; also covering coordinated and complex EU-wide litigation activities
  • Infringement and validity opinions, freedom-to-operate (FTO) analyses, due diligence

Andreas Oser was and is currently involved in many litigation cases, among others related to medical devices and important drug products.


chemistry, pharmaceuticals, life science and biotechnology, in particular:

  • medicaments and drugs (active substances, formulations), biopharmaceuticals
  • biological materials, DNA-related inventions and vaccines
  • therapeutic and diagnostic methods
  • medical products and devices and targeted drug delivery
  • polymers, fibre materials, composites
  • semiconductors, LEDs, OLEDs and other optical materials and optoelectronic devices,
  • batteries and their components

Publications and memberships:

Publications and memberships:

Schmidt T. and Oser A., GRUR Int 2019, 737: “New medical uses of known medical devices – A new perspective on purpose-limited product protection for medical devices in Europe”

Oser A. in GRUR Int 1998, 648 (=IIC 30, 1-18, 1999): “Patenting (Partial-)Gene Sequences”

Oser A., PATENTS & LICENSING 1998, 30: “EU Directive on Legal Protection of Biotech Inventions”

Oser A. and Bavec S., AIPPI Japan 2004 (Vol. 49 No. 7), 503: “Biotech Inventions in Europe”

Oser A. in GRUR Int 2006, 539 (=IIC 37, 520-550, 2006): “European Patent Litigation Agreement – Admissibility and Future of a Patent Dispute Regulation in Europe”

Thieme R„ Lay H., Oser A., Lehmann J., Wrissenberg S. and Boos W., Eur, J.Biochem. 160, 83-91 (1986)

Oser A., Roth W.K. and Valet G., Nucl. Acids Res. 16, 1181-1196 (1988)

Oser A. and Valet G., Nucl. Acids Res. 16, 8178 (1988)

Rothe G., Oser A. and Valet G., Naturwissenschaften 75, 354-355 (1988)

Oser A., Collasius M. and Valet G., Anal.Biochem. 191(2), 295-301 (1990)

Oser A. and Valet G., Angewandte Chemie International Edition 29(10), 1167-1169 (1990)

Rothe G., Banati R., Oser A., Assfalg-Machleidt I., Mangel W.F., Machleidt W., Kreutzberg G.W. and Valet G., Journal Immunol. Methods. 138(1), 133-135 (1991)

Oser A. and Valet G. (1988), Patent Applications WO8907606A, DE3804243A


Chamber of Patent Attorneys
epi – European Patent Institute
Member of the Biotech Committee of the epi
AIPPI – International Association for the Protection of Intellectual Property
FICPI – International Federation of Intellectual Property Attorneys
LES – Licensing Executives Society
GDCh – Gesellschaft Deutscher Chemiker

True greatness consists of being great in the little things.

Dr. Cheng Cheng

Dr. rer. nat., B.Sc., M.Sc. (Pharmacy)
Patent Professional

+49 89 69 39 21-0cheng@pruefer.eu

Professional career

Dr. Cheng Cheng has been working as a patent professional at Prüfer & Partner since March 2018. Dr Cheng Cheng studied and completed her Ph.D. degree under an EU research program in drug discovery at the Graduate School of Life Science of the University of Würzburg (Germany). Prior to her PhD study, she completed her Master’s degree in Pharmaceutical Science at the University of Strathclyde in Glasgow (UK), and a degree of Bachelor of Science (BS) in Pharmacy at the Shanghai University of Traditional Chinese Medicine (China). During her studies she also worked as a research assistant at the University of Strathclyde and as an internship student at AstraZeneca in Macclesfield in the UK.

Chinese, English, German (basic knowledge)

Specialist areas of activity


  • Dr. Cheng Cheng mainly handles patent prosecution and opposition matters before the European Patent Office.
  • Dr. Cheng Cheng was also involved in patent due dilligence


  • Pharmaceuticals
  • Biotechnology
  • Biochemistry
  • Medicinal chemistry
  • Metabolomics
  • Immunology
  • Microbiology
  • Natural products

Publications and memberships


Cheng C et al., Nat. Prod. Res., 2017 Dec; 31(23), 2818-2823

El-Hossary EM, Cheng C et al., Eur. J. Med. Chem., 2017 Jan; 126, 631-651

Cheng C et al., Tet. Lett., 2016 Sep; 57 (37), 4196-4199

Cheng C et al., Tet. Lett., 2016 June; 57 (25), 2786-2789

Horn H, Cheng C et al., Mar. Genomics., 2015 Dec; 24, 285-287

Abdelmohsen UR, Cheng C et al., Planta Med. 2015 Mar; 81(5), 382-387

Cheng C et al., PLoS ONE, 2015 Sep; 10(9): e0138528

Abdelmohsen UR, Cheng C et al., Mar. Drugs., 2014 Mar; 12 (3), 1220-1244


No memberships

All success comes from trust

Dr. Susanne Sonnenhauser

Dr. rer. nat., Dipl.-Biol., German Patent Attorney,
European Patent Attorney, European Trademark & Design Attorney

+49 89 69 39 21-0sonnenhauser@pruefer.eu

Professional career

Dr. Susanne Sonnenhauser has been a partner at Prüfer & Partner since 2008.
She completed her training as a patent attorney in a large law firm in Munich.
She also trained at the DPMA, the Federal Patent Court and the Patent Litigation Chamber of the regional court Munich, after graduating as Dr. rer. nat. at the Institute of Medical Microbiology, Immunology and Hygiene, Klinikum rechts der Isar (Technical University of Munich).
Before that, she studied biology at the Technical University of Munich specialising in microbiology, immunology and genetics.

German, English, French (basic knowledge)

Specialist areas of activity


  • Patent drafting
  • Patent prosecution, opposition and appeal proceedings
  • Preparation of expert opinions (freedom-to-operate, validity)
  • Innovation management


  • pharmacy (esp. pharmaceutical formulations)
  • biotechnology
  • biochemistry
  • immunology
  • virology
  • molecular biology
  • genetic engineering
  • medical technology

Publications and memberships


No publications


epi – European Patent Institute
Chamber of Patent Attorneys

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