Merck sues to block Cancidas generic

New Jersey-based pharmaceutical company Merck has sued generic drug maker Fresenius for infringing patents relating to its anti-fungal injection Cancidas (caspofungin acetate).

It filed the case at the US District Court for the District of Delaware last Thursday (August 7).

Merck holds a New Drug Application (NDA) for Cancidas, as well as two patents that cover it: 5,514,650, which is directed to compounds that are “found to have superior antibiotic properties”, and 5,952,300, which covers antifungal compositions.

The patents are due to expire in July 2015 and September 2017 respectively.

In June, Fresenius sent a letter to Merck, notifying it that it had submitted an NDA to the US Food and Drug Administration (FDA) seeking approval to market a caspofungin acetate injection. The letter alleged that the Merck patents are invalid and unenforceable, and would not be infringed by the Fresenius generic.

Merck argued in the complaint that Fresenius’s letter did not comply with FDA requirements, as it contained very limited information about the proposed Fresenius products.

The letter did not list any of the ingredients in the products, except for the active ingredient, or the amounts of any of those ingredients, it said.

Merck also accused Fresenius of placing unreasonable restrictions on who may view its NDA.

“The Fresenius offer did not allow any access to Merck’s in-house counsel, did not provide a reasonable provision for access by experts, and unreasonably limited the fields of practice of outside counsel,” Merck said in the complaint.

It added that before rejecting the offer it tried to negotiate with Fresenius to obtain a copy of the NDA; however, Fresenius’s final proposal continued to deny access to Merck’s in-house counsel.

Merck argued that by submitting the NDA, Fresenius is committing an act of infringement, and that selling the Cancidas generic would further infringe the patents.

It has asked for judgment that Fresenius has infringed the patents, a permanent injunction stopping Fresenius from making and selling its proposed caspofungin injections, and that the NDA is not approved by the FDA before expiration of the two patents.

On the same day, Merck filed a parallel action at the US District Court for the District of New Jersey to stop Fresenius infringing the patents at suit.