The person skilled in the art in the field of biotechnology is well defined by the case law of the boards of appeal. His attitude is considered to be conservative. He would never go against an established prejudice, nor try to enter unpredictable areas nor take incalculable risks. The notional skilled person would perform a transfer of technology from a neighbouring field to his specific field of interest, if this transfer involved routine experimental work comprising only routine trials (T 455/91, OJ 1995, 684; T 500/91; T 387/94; T 441/93; T 1102/00).

In T 60/89 (OJ 1992, 268) the board took the view that the skilled person in genetic engineering in 1978 could not be defined as a Nobel prize winner, even if a number of scientists working in this field at that time actually were awarded that prize. Rather he should be assumed to be a scientist (or team of scientists) working as a teacher or researcher in the laboratories which made the transition from molecular genetics to genetic engineering at that time.

This case law was confirmed in T 500/91 – "BIOGEN II". The board ruled that the average skilled person – who might also be a team of specialists in the relevant field – operated at a practical level, and the technical development which might normally be expected of him did not include solving technical problems through scientific research.

In T 223/92 the board had to consider the knowledge and capabilities of the notional skilled person in the field of genetic engineering as at October 1981, more than one year later than was the case in T 500/91. By this time, a considerably greater number of genes had been made the subject of cloning and expressing methods, and skills and experience in this technical field were developing rapidly. The knowledge of the notional person skilled in the art had to be considered as that of a team of appropriate specialists who knew all the difficulties still to be expected when considering the cloning of a new gene. However, the skilled person had to be assumed to lack the inventive imagination to solve problems for which routine methods of solution did not already exist.

From the notional skilled person nothing more can be expected than the carrying out of experimental work by routine means within the framework of the normal practice of filling gaps in knowledge by the application of existing knowledge (T 886/91, T 223/92, T 530/95, T 791/96).

In T 207/94 (OJ 1999, 273) the board stated that it had to be assumed that the average skilled person would not engage in creative thinking. Yet he or she could be expected to react in a way common to all skilled persons at any time, namely that an assumption or hypothesis about a possible obstacle to the successful realisation of a project must always be based on facts. Thus, in the board's view, an absence of evidence that a given feature might be an obstacle to carrying out an invention would not be taken as an indication that this invention could not be achieved, nor that it could.

In T 412/93 the patent related to the production of erythropoietin. The parties agreed that in this particular case the skilled person should be treated as a team of three, composed of one PhD researcher with several years' experience in the aspect of gene technology or biochemistry under consideration, assisted by two laboratory technicians fully acquainted with the known techniques relevant to that aspect. The composition of the team might vary depending on the knowledge and skills required by the particular aspect dealt with.

In T 455/91 (OJ 1995, 684) the board set out considerations on the skilled person's likely attitude to possible changes, modifications or adjustments to known products (e.g. a plasmid) or procedures (e.g. an experimental protocol). Its aim was to answer, objectively and avoiding any ex post facto analysis, the question whether it would be obvious to the skilled person to make given changes in a structure or procedure. The skilled person in this field was well aware that even a small structural change in a product (e.g. a vector, protein, or DNA sequence) or procedure (e.g. a purification process) could produce dramatic functional changes. He would therefore adopt a conservative attitude. For example, he would neither go against an established prejudice, nor venture into "sacrosanct" or unpredictable areas, nor take incalculable risks. However, within the normal design procedures, he would readily seek appropriate, manifest changes, modifications or adjustments involving little trouble or work and no or only calculable risks, especially to obtain a handier or more convenient product or simplify a procedure. See also T 867/13.

If, on the other hand, he would expect to have to perform scientific research rather than routine work in order to transfer a technology previously set up in one field of research (method of transforming Saccharomyces cerevisiae whole cells) to a neighbouring field (method of transforming Kluyveromyces whole cells), then inventive step could be acknowledged (T 441/93).

In T 493/01 the invention related to a protective antigen potentially useful in a vaccine against whooping cough. In T 455/91 (OJ 1995, 684) the skilled person in the field of biotechnology had already been defined as being cautious and conservative. The board said this did not mean he would refrain from considering information because it did not concern the mainstream of research in his field of specialisation or because it applied only to some parts of the world. His skill and knowledge were not geographically limited; in fact he would have a global point of view. Thus if, as in the case in point, a pathogen constituted a known threat in some restricted parts of the world, the skilled person would not refrain from taking prior knowledge about that pathogen into consideration or from using it as a basis for his activities.