2.11.7.7A Reach-Through Claims

Date Published

Note: The information in this part only applies to:

  • standard patent applications with an examination request filed on or after 15 April 2013.
  • innovation patents with an examination request filed on or after 15 April 2013.
  • innovation patents where the Commissioner had not decided before 15 April 2013 to examine the patent.  

For all other standard patent applications/innovation patents, see 2.11.7.7 Reach-Through Claims.


‘Reach-through’ claims define compounds in terms of specified properties identified in a screening method or assay.  This style of claim is more prevalent in the chemical and biochemical areas.  

Claims to Reach-Through Compounds

Each application should be assessed on its own merits, based on a proper construction of the specification and the facts of the case.  In general, claims to unspecified ‘identified’ compounds per se are speculative.  Such claims encompass any compounds identified as possessing the properties being screened for, regardless of whether they have been explicitly disclosed in the specification.  


Enablement for ‘Identified’ Compounds

If the relationship between the function of the compounds and their structural features is not defined, screening all compounds to identify those with the desired properties would impose an undue burden in requiring substantial experimentation by trial and error.  Therefore, in most cases, claims to unspecified ‘identified’ compounds per se will not be sufficiently enabled over the whole scope of the claim and for this reason will not satisfy the requirements of sec 40(3) or sec 40(2)(a).  

A claim to a specified compound per se, which is explicitly disclosed in the specification, may be enabled by that disclosure if sufficient information is provided to make or otherwise obtain the compound.


Compounds and the Contribution to the Art

A screening assay does not produce a new compound; it identifies the properties of an existing compound.  Prima facie, any compound ‘identified’ by such an assay already existed prior to the testing process and will not be novel.  Consequently, where the disclosure is directed to a method of screening known compounds, the contribution to the art will reside, not in the compound per se, but in the consequential uses of the compound (based on the properties identified by the screening assay).  

Claims to pre-existing compounds, merely identified as having a particular activity, will be prima facie not novel.  In these circumstances, examiners are not required to locate a citation to support the lack of novelty objection.  Such claims to identified compounds per se, whether explicitly disclosed in the specification or not, will also be broader than is justified by the applicant’s contribution to the art and will lack support under sec 40(3).  

Where overcoming a novelty objection will fully address any objection under sec 40(3), examiners may simply note in the novelty objection (or in a separate objection), either that an opinion under sec 40(3) is reserved, or alternatively that the reasons provided would also form the basis for an objection under sec 40(3) (see also 2.4.12.1.10 Reach-Through Claims for further information on novelty considerations).  


Claims to the Use of Reach-Through Compounds

In some circumstances, claims to the downstream uses of functionally defined, but otherwise unspecified ‘identified’ compounds, may be fully enabled.  Each application should be assessed on its own merits, based on a proper construction of the specification and the facts of the case.

It is reasonable and necessary under sec 40(3), to limit the subject matter of the claims to the contribution to the art.  Where a specification discloses a principle of general application in respect of the use of unspecified ‘identified’ compounds, a claim will be supported, provided it is restricted to the use of the ‘identified’ (i.e. functionally defined) compounds in a practical application of the general principle.  

For example, an applicant has discovered that inhibiting the activity of protein X leads to the effective treatment of disease Y.  The specification includes data establishing that the treatment is a reality and not just a possibility (see 2.11.7.10A Support Required for Pharmaceutical Inventions and Methods of Treatment), and discloses a screening assay to identify compounds capable of inhibiting the activity of protein X.  In this situation, the contribution to the art will lie in the screening assay itself and the method of treating disease Y by inhibition of protein X, provided both are novel and inventive.  

Thus, a claim to the use of an inhibitor of protein X to treat disease Y would be enabled over its whole scope for the purposes of sec 40(2)(a) and sec 40(3), even though only a small number of the inhibitory compounds are explicitly disclosed.  The reason for this is that the feature ‘inhibitor of protein X’ represents a principle of general application; given the disclosure outlined above, the person skilled in the art would reasonably expect the claimed therapeutic method to work using anything that falls within the scope of the term ‘inhibitor of protein X’.  

Consequently, the method will be enabled over the whole scope of the claim where the applicant has exemplified the method of treatment using one such inhibitor.  Furthermore, by providing a screening assay, alternative ways of performing the invention are at the disposal of the skilled addressee, which would be apparent upon reading the description, based on his common general knowledge (T 484/92).

Note that a specification relating to a method of treatment containing similar claims (use of an inhibitor of protein X to treat disease Y), but which contains no screening assay, will nevertheless be enabled across the whole scope of the claim where a relevant screening assay would be obvious to the skilled addressee on the basis of the common general knowledge in the art.  In this situation, the specification is not required to detail such an assay.