Merial, the patentee of South African Patent No. 1996/8057 relating to an anti-parasitic ‘spot-on’ composition for pets containing fipronil and a crystallisation inhibitor, alleged that Cipla Vet infringed its patent by manufacturing and selling a competing product, Fiprotec. Cipla denied infringement and challenged the validity of the patent on several grounds, including lack of clarity, insufficiency and inutility. The Commissioner of Patents held that Merial failed to prove infringement, although most validity attacks were rejected. Merial appealed to the Supreme Court of Appeal.
The appeal was upheld with costs, including the costs of two counsel. The order of the Commissioner of Patents was set aside and replaced with an order interdicting Cipla from infringing the specified claims, directing delivery up of infringing products, ordering an inquiry into damages or a reasonable royalty, certifying the relevant claims as valid under section 74 of the Patents Act 57 of 1978, and awarding Merial its costs.
The case is an important authority on patent clarity in South African law. It confirms that claims are not unclear merely because components may perform more than one function, provided that a skilled addressee can understand the scope of the monopoly. The judgment reinforces a purposive, practical approach to patent interpretation and cautions against reliance on artificial or ‘mythical’ hypotheticals to attack validity.