Oldie but goldie - when is old prior art a suitable starting point for inventive step analysis?

Fig. 1 from EP 1 571 938

Nike Intl is the owner of EP 1 571 938 "footwear incorporating a textile with fusible filaments and fibers". With decision of 13 November 2014, the German Federal Patent Court declared all claims (and auxiliary claims) invalid for lack of inventive step starting from the German published examined application ("Auslegeschrift") DE 1 085 173 of 1954 in combination with US 2,440,393 of 1948. On appeal, the Federal Court of Justice upheld the Federal Patent Court's decision (X ZR 119/14 of 31 January 2017, reasons published on 30 March 2017).

One key issue was whether DE 1 084 173, published almost 50 years before the priority date of Nike's patent, was a suitable starting point for inventive step analysis. Would the person skilled in the art, when seeking to increase wear resistance and stiffness of shoes with textile uppers while maintaining their comfort (as the court defined the problem, at para. 10), in 2002 consider prior art from the early 1950s as a suitable starting point?

The BGH first reminded everybody that according to its long standing practice, the mere fact that a prior art document is ex post the "closest" prior art (in the sense of having the most structural features in common with the invention) is not sufficient to make it a suitable starting point for inventive step analysis (see BGHZ 179, 168 - Olanzapin; decision of 5 October - X ZR 78/14, GRUR 2017, 148 - Opto-Bauelement). The choice of a suitable starting point requires a justification, which is generally found in the skilled person's desire to find a better or different solution for a specific purpose (at para. 28, with reference to the before cited decisions).

State of the art in 1954...

It is a matter of the specific circumstances of the case whether the skilled person , in addition to current technical solutions which are taken into account as a matter of course, also considers older prior art. Whether the skilled person considers older prior art depends on the development cycles in the industry, but also on non-technical factors such as fashion trends in the apparel and shoe industry. In any case, disregarding older prior art as suitable starting point for inventive step analysis requires a "particularly careful reasoning", as not taking into account such prior art may lead to the patentability of merely re-discovered old concepts (at para. 29). The court here seems to qualify some statements in its jurisprudence that may have been taken to indicate that the age of a prior art document is a factor that generally counts against its suitability as starting point for prior art analysis (see, e.g., decision X ZR 57/14 of 10 January 2017, para. 40).

In the case at hand, there were factors that led the skilled person to consider older prior art. Besides the trend towards light yet stable shoes with textile uppers specifically in the sport shoe field, the court notes that there is a trend to "retro chic" or "retro look" in the sporting apparel industry which would lead the person skilled in the art to also consider technical solutions from bygone eras (at para. 31). Therefore, the Federal Patent Court was correct in choosing DE 1 084 173 as a starting point for inventive step analysis, and starting from DE 1 084 173 in combination with US 2,440,393 the main claims and all auxiliary claims were invalid for lack of inventive step.

The take-away for the practitioner is that merely arguing that a document is not a suitable starting point for inventive step analysis because of its advanced age has become harder after this decision (designated a "Leitsatzentscheidung"). A particularly careful reasoning ("besonders sorgfältige Prüfung") is required before disregarding such documents.