For the second time this month, the US International Trade Commission has agreed to investigate a complaint hinging on a patent dispute involving different drugmakers. This time around, Femina Pharma accuses Merck and numerous retailers, including CVS Caremark Wal-Mart, of infringing on a patent because the drugmaker and pharmacies import or sell Merck’s NuvaRing vaginal ring birth control device (see the ITC notice).

In its complaint, Femina argues its patent generally relates to a medicated intravaginal device, such as a vaginal ring, for transvaginal delivery of a medication to a woman’s uterus. Femina also maintins the drug delivery system described in its patent allows delivery in lower concentrations than those needed for systemic treatment and so offers a lower systemic concentration and fewer side effects (see the Femina complaint here).

NuvaRing is one of the many products that Merck obtained as part of its acquisition of Schering-Plough and was the biggest seller in its portfolio of women’s health products. Last year, NuvaRing, which contains estrogen and progestin, generated $559 million in sales (see page 6 of the Securities and Exchange filing here). Schering-Plough, by the way, itself obtained NuvaRing after acquiring Organon, a unit that Merck is trying to dismantle in the Netherlands (see this), where Organon was once based.

Earlier this month, Eli Lilly convinced the ITC to investigate its complaint that Hospira and three suppliers are using a manufacturing process that infringes a patent on its Gemzar cancer med in hopes of blocking imports of Hospira’s generic version (back story).

Hat tip to ITC 337 Law blog