6.5. Reach-through claims

In T 1063/06 (OJ 2009, 516) the board held that a formulation of a claim whereby functionally defined chemical compounds were to be found by means of a new kind of research tool using a screening method set out in the description constituted a reach-through claim which was also directed to future inventions based on the one now being disclosed. The applicant was entitled to claim patent protection only for his actual contribution to the art and not to reserve an unexplored field of research.

In case T 3122/19 (identifying a subgroup of cancer patients for treatment with FGFR inhibitors), the opponent argued – based on T 1063/06 – that the skilled person was not able to identify all compounds falling within the broad dual-function definition of the claim without undue burden and, accordingly, such alternatives were not available to the skilled person. The board considered the invention underlying the case at hand was not the same situation as in T 1063/06, in which any kind of compound (without guidance in terms of chemical structure or other selection rules) would have to be screened for the desired enzyme-stimulating activity. In the case at hand, the functional definition had two levels. As a consequence there was a large pool of candidates. Testing for the second level activity against cancer cells (as described in the application as filed) would not have had to be carried out by trial and error on randomly selected compounds, but only on a limited selection of compounds. No evidence was provided to show that a large proportion of FGFR inhibitors would fail this test (in which case identifying active compounds would be an undue burden on the skilled person).

Decision T 1170/20 deals with reach-through claims. The appellant (opponent) asserted that the feature "an electrically insulating gas containing at least one fluorinated compound with a global warming potential (GWP) of less than 3 500" meant that the claim was a reach through claim, i.e. that the claim related to a chemical compound defined in functional terms only. The board agreed with the appellant. By contrast, the board disagreed with the respondent's (patent proprietor's) assertion that "the patent contains sufficient information to enable a person skilled in the art to find, with reasonable effort, appropriate variants of fluorinated compounds suitable for the electrically insulating gas of the medium and/or high-voltage gas-insulated electrical apparatus defined in claim 1 of the patent". In the board's view, the contested patent did not appear to state any criteria, general information or general guidelines that might guide the skilled person to find – among the broad classes of claimed compounds – those that satisfied the constraints imposed by the claim. The respondent also maintained that considering the claim at issue to be a reach-through claim was a misapplication of the Guidelines F‑III.9. – November 2019 version. According to the respondent, that chapter of the Guidelines related to biotechnology inventions and, even more crucially, to compounds characterised solely by their effect or function. That was not the case here as GWP was an accepted, common parameter that was easy to determine for any given compound. However, contrary to the respondent's assertion, the technical field of a claim is immaterial if the claim is deemed to be a reach-through claim. The fundamental notion of not allowing reach-through claims is explained in the above-mentioned chapter of the Guidelines. The claim at issue covered all compounds that have a GWP of less than 3 500 and act as a medium and/or high-voltage insulating gas. The patent did not clearly identify those compounds apart from indicating that they contained fluorine. The board stressed that finding suitable compounds would pose a challenge. The respondent merely maintained – without furnishing any evidence – that a person skilled in the art would be able to find suitable compounds using ordinary skill alone and that the GWP could be determined for any suitable compound. However, that was exactly the case described in the Guidelines – the respondent was attempting to patent what had not yet been invented, and the fact that it was possible to test for the effects used to define the compounds did not confer sufficiency on the claim. The claim in fact constituted an invitation to perform a research programme.