Amylin Pharmaceuticals has filed a lawsuit against long-time diabetes drug partner Eli Lilly, claiming that the latter's recent link-up with Boehringer Ingelheim is unlawful and breaches their pacts covering exenatide.

In 2002, Amylin signed an alliance with Lilly for the big-selling injectable Byetta (exenatide) and the firms are also partners, along with Alkermes, for the once-weekly version Bydureon, The latter has been recommended for approval in Europe (where it will be sold by Lilly) but received a complete response letter from the  US Food and Drug Administration.

However, in January, Lilly signed a wide-ranging diabetes collaboration, one of the key elements being the oral dipeptidyl peptidase-4 (DPP-4) inhibitor Tradjenta (linagliptin). That drug was approved by the FDA earlier this month.

'Improper, anticompetitive behaviour'

This has led to the lawsuit from Amylin which is seeking, among other things, a preliminary and permanent injunction. The firm alleges that Lilly is engaging in "improper, unlawful and anticompetitive behaviour" as  linagliptin "will compete directly with Amylin's exenatide products". Specifically, it hopes the courts will prevent Lilly from proceeding with its plans to use the same sales force to sell both exenatide and the Boehringer drug.

Amylin goes on to say that it selected Lilly as a partner to promote development and maximise sales of exenatide products. As such, "we are disappointed that we could not resolve this matter amicably and that we were forced to bring legal action to protect our rights, our products and our shareholders", Amylin states, adding that "notwithstanding this litigation, we intend to continue to collaborate with Lilly".

Lilly's head of diabetes, Enrique Conterno, responded by saying the lawsuit and motion for a temporary restraining order, filed in California, is without merit and the firm "will vigorously defend our position". He went on to say the company "has been and remains fully committed to fulfilling its obligations under its exenatide collaboration agreement with Amylin, as well as to complying with all laws and regulations. We look forward to building on the alliance's success achieved to date".

The company added that it has "devoted significant talent, resources, and know-how to the collaboration's efforts and has been instrumental in the success" of Byetta and the development of Bydureon. It concluded by saying "the alliance" plans to submit a response to the FDA's complete response letter in the second half of the year.

Supreme Court rejects Gemzar patent appeal

Meantime, Lilly suffered a further setback on the news that the US Supreme Court has left intact a federal appeals court decision last July invalidating its patent on the chemotherapy Gemzar (gemcitabine).

The firm had been looking to protect Gemzar from generic competition in the USA until May 2013, but the Supreme Court, without comment, refused to hear Lilly's appeal in the case originally won by India's Sun Pharmaceutical Industries. Copycat versions became available across the pond in November.