The Oxford South African dictionary defines coterminous as "to have the same boundaries or extent"; while the Cambridge dictionary defines coterminous as "to have or meet at a shared border or limit". It is clear from both definitions that coterminous means to have the same boundary.
In Pharma Dynamics (Pty) Ltd v Bayer Pharma AG and Another 2014 BIP 69 (SCA) (the Pharma case), the Supreme Court of Appeal (SCA) held that a divisional patent application may have broader or narrower protection of the inventions claimed in the parent application, but the claims of the parent and the claims of the divisional may not be "coterminous".
In the Pharma Case, Pharma Dynamics appealed the decision of the high court to grant Bayer an interdict against them. The interdict was to stop Pharma Dynamics, through the sale of the contraceptive product Ruby, from infringing South African patent number 2004/4083. Patent number 2004/4083 is a divisional patent based on South African patent number 2002/1668. The question that the SCA had to answer was, inter alia, whether South African patent number 2004/4083 is a true divisional of parent patent number 2002/1668.
The parent patent and divisional patent had only one claim each. When the judge reviewed the parent patent and divisional patent, he reviewed only Claim 1 of each patent and concluded that the two claims are not coterminous since they cover different scopes. Claim 1 of the divisional patent is broader in scope than Claim 1 of the parent patent. The court held that the parent patent and divisional patent have, for practical purposes, the same text because the inventions disclosed are the same. The difference lies in their respective claims, and in variation of the text as a result of the dividing process. Further, the court held that one of the features of the divisional system is that each divisional must have claims which are different, and the patentee cannot have the same claim in different patents.
The Pharma case, however, does not answer the question of whether the claims of the parent patent and divisional patent must be viewed as a whole, or individually, in order to decide whether the claims of the parent and divisional patent are coterminous (only Claim 1 of the parent and the divisional patent were reviewed in the Pharma case). This will be relevant in a situation where the parent has, for example, two claims: Claim 1 directed to compound A, and Claim 2 directed to compound A in combination with a compound B, and a divisional patent with one claim directed to compound A and a compound B in combination. In this situation, the overall claims of the parent patent and divisional patent are not the same,since the divisional patent does not have Claim 1 of the parent patent (claim directed to compound A only). However, Claim 2 of the parent patent is the same as Claim 1 of the divisional patent. If we are to adopt a broad interpretation of "coterminous", looking at the claims as a whole, then the claims of the parent and divisional patent are not coterminous in the above scenario. Alternatively, if we are to adopt a narrower interpretation of "coterminous", looking at the individual claims, then the claims of the parent patent and divisional patent are coterminous in the above scenario, since Claim 2 of the parent patent is the same as Claim 1 of the divisional patent. To avoid the claims of the parent patent being coterminous with the divisional patent, it would be necessary to delete Claim 2 of the parent patent if a narrower interpretation of coterminous is adopted.
To determine whether a broad or narrow interpretation of coterminous should be adopted, it is helpful to review the position in other jurisdictions.
In Australia, s64(2) of the Australian Patents Act, 1990 provides that where a patent application claims an invention that is the same as an invention that is the subject of a patent and is made by the same inventor; and the relevant claim or claims in each of the complete specifications have the same priority date or dates; a patent cannot be granted on the application.
In practice, as was held in Arbitron v Telecontrol Aktiengesellschaft 2010  FCA 302, having claims of the same scope in a parent and a divisional patent is not permitted in Australia. In this case, Claims 1 to 4 of the divisional patent covered substantially the same scope as Claims 17 to 20 of the grandparent patent. At paragraph 159 of the judgment, the court held, "I consider that the invention claimed in the Patent is the same as an invention that is the subject of the Grandparent Patent. That being so, it follows that Section 64(2) was enlivened to prohibit the grant of the Patent on the application filed on 12 July 2000". Australia, therefore, adopts a narrower interpretation of 'coterminous'.
In New Zealand, Regulation 82 (b) and (c) of the New Zealand Patent Regulations provides that the divisional application must not include a claim or claims for substantially the same matter as accepted in the parent application, and vice versa, in the case of a parent application where the divisional application has been accepted first. In practice, a parent application and a divisional application cannot be accepted if each is claiming substantially the same matter in one or more claims in New Zealand. New Zealand, therefore, adopts a narrower interpretation of 'coterminous'.
In the United Kingdom, s18(5) of the Patents Act, 1977 provides that where two or more applications for a patent for the same invention having the same priority date are filed by the same applicant or his successor in title, the comptroller may, on that ground, refuse to grant a patent in pursuance of more than one of the applications. Further, s73(2) gives the comptroller the power to revoke a patent for the same invention having the same priority date, where the patent applications were filed by the same applicant. The wording of sections 18(5) and 73(2) seems to suggest that the United Kingdom adopts a broad interpretation of 'coterminous'. However, in the matter of two applications for patents by Dreyfus in May 1927, a narrower interpretation of 'coterminous' was adopted by the assistant comptroller. In this case, Dreyfus filed two patent applications on the same day, and each application contained at least one claim which was the same as a claim in the other application. The assistant comptroller, acting for the Comptroller General, held that the grant of the two patents covering the same subject matter might well be inconvenient for the public, and he refused to allow the applications to proceed in the form in which they stood. The decision of the assistant comptroller was upheld by the law officer in an appeal filed by the applicant, Dreyfus. The law officer, therefore, adopted a narrower interpretation of 'coterminous'.
Having regard to the interpretation of "coterminous" in other jurisdictions, in the writer's view, it is probable that the South African courts will adopt a narrower interpretation of coterminous when faced with similar facts in future. We must remember that the patent system is based on a quid pro quo. The inventor or patentee discloses his or her invention to the public and, in return, enjoys the fruits of his or her invention to the exclusion of others for a limited period. The system is designed to give the patentee enforceable rights for his or her invention using a patent; in other words, for one invention, one patent. If, for example, the patentee is allowed to have the same claim or claims in five different divisional patents, the patentee can arguably enforce all five divisional patents against an infringer who has a product that infringes on the said claim(s). If the patentee is allowed to have the same claim in one divisional, by the same reasoning, he or she can have the same claim in as many divisional patents as he or she chooses, depending on the importance of the claim to the patentee. As was held in the Dreyfus case, this is not the object of the patent system.
Being coterminous is not one of the nine grounds for revoking a patent in South Africa. So, what is the consequence if the claims of the parent patent are coterminous with the claims of the divisional patent? If a third party is of the view that the claims of a parent patent are coterminous with the claims of a divisional patent, the remedy would be for the third party to seek to set aside the divisional patent in a review application, as suggested in the Pharma case.
Mhangwane is an Attorney with Spoor & Fisher.