Teva and Amneal lose patent battle against Mallinckrodt

Ireland-based biopharmaceutical company Mallinckrodt and Endo, a US healthcare business, have won a patent case against Amneal and Teva.

The ruling, which took place at the US District Court for the District of Delaware on Friday, October 7, upheld the validity of US patent number 8,871,779.

Endo was granted a licence to use Mallinckrodt’s invention of creating oxymorphone with low ABUK (alpha, beta-unsaturated ketone), described in the ‘779 patent, which expires in November 2029.

The case arose in 2014 after Amneal and Teva filed Abbreviated New Drug Applications with the Food and Drug Administration (FDA) seeking to manufacture and sell generic versions of Endo’s Opana (oxymorphone) product, a treatment for moderate to severe pain

First, Teva argued that the method for lowering ABUK oxymorphone claimed in the ‘779 patent rendered it obvious and therefore invalid.

The ruling stated that Teva and Amneal argued that “an ordinary-skilled artisan would have had a reasonable expectation of success in ... lowering the level of oxymorphone ABUK to below 10 ppm”.

Teva further argued that, because it purchased two batches of low ABUK oxymorphone hydrochloride from Mallinckrodt in 2010 and 2011, the court should grant it an implied licence to practise the ‘779 patent.

But Judge Richard Andrews rejected Teva’s argument, finding that previous sales of a product without ongoing obligations to supply more do not create a licence.

He added that Teva and Ameal had failed to provide clear and convincing evidence that any of the asserted claims of the ‘779 patent are invalid.

Before 2002, manufacturers of oxymorphone hydrochloride were aware of the presence of the impurity now known as oxymorphone ABUK.

In 2002, the FDA informed Mallinckrodt that it was concerned about the levels of ABUK in certain products.

The FDA informed Mallinckrodt that it would impose limits on the levels of ABUK, and that it might require limits as low as 0.001% (10 ppm) ABUK.

In 2005, Mallinckrodt succeeded in reachin g the low ABUK levels mandated by the FDA for oxymorphone hydrochloride.

Mallinckrodt applied for a patent on its new low-ABUK oxymorphone product and the ‘770 patent was granted.

Jeffrey Toney, partner at Kasowitz, which was representing Mallinckrodt, said: “These Mallinckrodt scientists accomplished something extraordinary.”

He added: “No other witness at trial had ever manufactured a drug with less than 10 ppm of a process impurity. We are pleased that the court recognised the importance of their work.”