Mylan accused of infringing oestrogen patch patents

Japanese pharmaceutical company Hisamitsu and its US-based subsidiary Noven have sued Mylan for allegedly infringing two patents covering oestrogen patch Minivelle (estradiol).

Minivelle is a twice-weekly transdermal patch used to reduce hot flashes during menopause, and to prevent weakening of bones.

Hisamitsu and Noven filed the case at the US District Court for the District of Delaware last Thursday (April 23) after Mylan filed an Abbreviated New Drug Application with the US Food and Drug Administration (FDA) seeking approval to market a generic version.

Minivelle has two unexpired patents protecting it that are listed in the Orange Book, both of which are involved in the suit.

Hisamitsu owns US patent 6,841,716, called “patch”, which is due to expire in April 2020. Noven’s patent, US number 8,231,906 and called “transdermal oestrogen device and delivery”, will expire in July 2030.

A third patent covering the drug, called “solubility parameter based drug delivery system and method for altering drug saturation concentration”, expired last August.

In its ANDA, Mylan said that it plans to make a generic Minivelle product in all but one of the five dosage strengths that the drug is available in. It also claimed that the ‘716 and ‘906 patents are invalid and unenforceable.

Hisamitsu and Noven have asked for a judgment that Mylan has infringed the patents by filing the ANDA and for an order that stops the FDA from approving the ANDA before the last Minivelle patent expires.

The pair has also asked for a permanent injunction to stop Mylan from marketing a generic, and damages.