Supreme Court of Canada rules that prediction of use based on fact at the date of Patent application satisfies requirement of “inventive concept”

Supreme Court of Canada rules that prediction of use based on fact at the date of Patent application satisfies requirement of "inventive concept"

The Supreme Court of Canada has recently rejected a challenge by Novopharm Ltd. and Apotex Inc., Toronto-based generic drug manufacturers who claimed the right to market cheaper generic copies of AZT, thereby ending a long-running legal battle to revoke the Canadian patent held by competitor Glaxo Wellcome Inc. on AZT, one of the earliest and still one of the most important drugs used to combat AIDS (Acquired Immune Deficiency Syndrome).

The Court held that Glaxo Wellcome Inc., had established its scientific claims for purposes of the federal Patent Act and was entitled to legal protection.

Glaxo Wellcome , the Canadian subsidiary of the British pharmaceutical company of the same name, was not the inventor of AZT, which was developed by a U.S. researcher in the 1960s.

The drug was seen at first as a potential weapon against cancer but proved disappointing and was not patented for that purpose. Glaxo started experimenting with AZT some two decades later, in the hope it might prove effective in retarding the HIV virus that causes AIDS.

A key issue in the case was the evidence Glaxo produced to support its claim of a new use for AZT when it applied for a patent in 1985.

Glaxo had conducted laboratory tests on cells taken from mice but the test on human cells was transferred to the U.S. National Institutes of Health (NIH). Glaxo speculated that the drug AZT would work in humans against the HIV retrovirus. In February 1985, two NIH scientists verified that AZT inhibited HIV replication. On March 16, 1985, Glaxo filed a patent application. Apotex and Novopharm , challenged the validity of the patent on the grounds that the element of utility had not been established as of the priority date of the patent, and that the disclosure was misleading because it omitted any reference to the NIH co-inventors.

The trial judge declared certain of the patent claims to be valid and infringed. The Federal Court of Appeal dismissed the appeal and Apotex and Novopharm appealed before the Supreme Court.

The Supreme Court rejected claims by Novopharm and Apotex that the U.S. researchers were, in effect, co-inventors whose work had been appropriated by Glaxo for its own profit.

The Court said that though the NIH research provided crucial evidence, it was Glaxo that provided the key "inventive concept" of using AZT to combat AIDS.

The Court also rebuffed claims that Glaxo did not provide enough preliminary proof of effectiveness against AIDS to support its patent application.

By the date that the patent was applied for, the respondents Wellcome Foundation and others, had sufficient information about AZT to make a sound prediction that it would be useful in the treatment and prophylaxis of HIV in humans. The doctrine of sound prediction had three components. There had to be a factual basis for the prediction at the date of the patent application, the inventor had to have a sound line of reasoning from which the desired result could be inferred, and there had to be proper disclosure. Each of these requirements has been met in this case. In the steps leading to patentability, the inventor could utilize the services of others, but they would not be co-inventors unless they participated in the inventive concept, as opposed to mere verification. Therefore, the NIH scientists were not co-inventors.