FIVE BURROUGHS WELLCOME AZT PATENTS UPHELD ON APPEAL; SIXTH IS REMANDED TO LOWER COURT FOR FURTHER PROCEEDINGS: NOVOPHARM WILL PRESS ON WITH LITIGATION

Five of Burroughs Wellcome's six patents for AZT (Retrovir, zidovudine) are valid, the D.C. federal appeals court ruled Nov. 22. The three-judge panel reviewed a July 1993 New Bern, N.C. federal court ruling that Wellcome was the sole inventor of AZT. The defendants in the New Bern case, Barr and Novopharm, claimed that the National Institutes of Health should also have been named as an inventor. "On the facts before us, it is apparent that the district court correctly ruled against Barr and Novopharm as to five of the patents" (numbers 4,724,232, 4,828,838, 4,833,130, 4,837,208 and 4,818,538), the appeals court said.

On the sixth patent (number 4,818,750), the appeals court ruled that the lower court decision "was premature" and remanded that issue for further proceedings.

One of the litigants, Barr Labs, said "it would study the lengthy decision before determining how to proceed." The company said it is "disappointed in the ruling" because it "substantially affirmed the decision of the federal court in New Bern." Barr added that "FDA recently completed a pre-approval inspection" for the company's version of AZT.

Novopharm vowed Nov. 23 to continue litigation over the '750 patent. The company "is prepared for a trial by jury" on the issue. Novopharm claims that "if we prove the '750 patent is invalid, that means all the AZT patents are invalid and we can produce generic AZT."

Burroughs Wellcome noted, however, that "the trial court's injunction against Barr and Novopharm will remain in full force and effect." The injunction prohibits the companies from manufacturing or selling AZT in the U.S. until the expiration of the '232 patent in 2005.

The appeals court reviewed the lower court's interpretation of the definition of conception which did not require that Wellcome have a reliable prediction that its product would work when it conceived the invention and filed for a patent ("The Pink Sheet" July 26, 1993, p. 8).

"An inventor need not know that his invention will work for conception to be complete," the appeals court wrote. "He need only show that he had the idea; the discovery that an invention actually works is part of its reduction to practice."

The court found that Novopharm should be given the chance to present its evidence on the '750 patent at the trial court level. The patent concerns the claim that AZT increases the number of T- lymphocyte cells in an AIDS patient, whereas the other five patents concern use of AZT for treatment of AIDS in general. Novopharm alleged that the only direct evidence for such a claim came from Phase I trials conducted by NIH researchers Robert Yarchoan, MD, and Samuel Broder, MD, before the patent was filed by Burroughs Wellcome ("The Pink Sheet" July 19, 1993, T&G-15).

The appeals court ruled that although the U.S. Patent & Trademark Office determined that the effect of increased levels of T-cells following treatment of AIDS would be obvious to "those skilled in the art" of AIDS treatment, this is "irrelevant" as to whether the Burroughs Wellcome inventors conceived of this use of AZT. "For conception, we do not look to whether one skilled in the art could have thought of the invention, but whether the alleged inventors actually had in their minds the required definite and permanent idea," the court said. "The record does not now support resolution of this question as a matter of law."

One of the three appeals court justices, Alan Lurie, dissented from the panel's decision to remand the '750 patent for further litigation. "I believe that the method of the '750 patent is an inherent, inevitable result of the practice of the other method patents claiming treatment of HIV or AIDS," he wrote.