Patents

Case Note American Home Products Corporation and Another v Novartis Pharmaceuticals UK Ltd. and Another

John Lambert

27 July 2000
Last updated 15 Nov 2005

This article formerly appeared on the Old Colony House website

This appeal from the judgment of Laddie J (American Home Products Corporation and Another v Novartis Pharmaceuticals UK Ltd. and Another [2000] RPC 547) concerned the second medical use of rapamycin, a product known to have anti-fungal and anti-tumour properties, in the preparation of a medicament for inhibiting organ or tissue transplant rejection. Claim 1 of the patent for that invention claimed simply:

"Use of rapamycin for the preparation of a medicament for inhibiting organ or tissue transplant rejection in a mammal in need thereof."

The Issues

The claim had been drafted in this way to overcome two difficulties

	the first being that rapamycin was already known, and
	the second that s. 4 (2) of the Patents Act 1977 precludes an invention of a method of treatment of the human or animal body by surgery or therapy from being capable of industrial application within the meaning of section 1 (1) (c) of the Act.

However, s.1 (3) provides that nothing in s. 1 (2) shall prevent a product consisting of a substance or composition being capable of industrial application merely because it is invented for use in surgery or therapy.

The issues were whether the use of a medicament known as an immunosuppressant for inhibiting organ or tissue transplant rejection derived from rapamycin infringed the patent, and, if it did, whether the patent was invalid for insufficiency.

Infringement

The trial judge had construed claim 1 so as to include "such derivatives of rapamycin as exhibit the same type of inhibition to organ rejection as rapamycin itself does." As the defendants had produced an immunosuppressant that had been derived from rapamycin it followed that they had infringed. Their first contention on appeal was that the construction of claim 1 should be confined to rapamycin.

Applying Hoffmann J's Improver test, the case fell at the first hurdle. The invention was for a second medical use of a known product. Posing the question would the derivative of rapamycin have a material effect upon the way that rapamycin works was a nonsense. Were the question posed in the way that the patentee contended, namely rapamycin and any derivative that worked like rapamycin, the patent would be invalid for insufficiency. In the circumstances it was not strictly necessary to consider the second and third Improver questions, but the Court answered the question, whether it would have been obvious to a skilled addressee that the variant would not have a material effect on the way the invention worked as "no", and the question, whether such skilled person would have understood from the language of the claim that the patentee intended strict compliance with the primary meaning as an essential requirement of the invention as "yes".
The reasons for the affirmative finding were that the specification itself distinguished between rapamycin and its derivatives. As it had focussed on the discovery of the immunosuppressant properties of rapamycin, it would have been surprising had the patentee described the invention in wider terms. It would have been easy enough for the patentee to broaden his claims to embrace derivatives had he so wished but he
declined to do so, probably because such claims would have been rejected by the EPO. The Court therefore allowed the appeal.

Insufficiency

Had the patent been construed in the way that the patentee contended, it would have been revoked on the ground that the specification did not disclose the invention clearly enough and completely enough for it to be performed by a person skilled in the art (s. 72 (1) (c) of the Patents Act 1977). There were many derivatives of rapamycin and not all of them had immunosuppressant properties. To identify such derivatives would have required further work and taken a long time. It was the duty of the patentee to
provide a description which enables the skilled person to perform the invention, not to supply a starting point for a research programme. Having construed the patent in a way that limited the invention to rapamycin it was sufficient.

 

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