In a victory for Eli Lilly, a federal court judge late yesterday vacated a temporary injunction that Amylin Pharmaceuticals had won in a bid to prevent the big drugmaker from using the same sales force to sell Byetta - which both currently promote - and a rival drug made by Boehringer Ingelheim. Lilly recently struck a development and marketing deal with Boehringer.

The move underscores the heated battle between Lilly and Amylin, which have worked together to develop a follow-up to Byetta called Bydureon, which is awaiting approval from the FDA. Amylin, however, filed suit against Lilly over charges the deal with Boehringer was a strategic breach of their contract that would cause irreparable harm (back story here and here).

“What they’ve done is, they’ve taken the people that we have trained year after year to understand what our story is…and they’ve taken them and they assigned them to (Boehringer’s) product. How is that not injury? I mean, now those people know what our answers are. They know what our weaknesses are. They know what our strengths are,” Cliff Aronson, a lawyer for Amylin argued, according to a transcript of the hearing obtained by ThomsonReuters.

However, US District Court Judge Janis Sammartino decided that Amylin failed to show “that it will suffer any irrreparable injury from any misuse of its confidential information.” How so? She opines that Amylin is only speculating that the Lilly sales force will disclose such info. And she also states that Amylin has failed to show any loss of customers or loss of goodwill (read the order here).

She reached this decision after hearing Lilly lawyers maintain the Boehringer drug is intended to replace the Amylin drug, but instead remain a complementary product in its portfolio. “We’re in this for the long run (with Amylin),” Covington & Burling attorney Mike Imbroscio told the judge, according to the transcript. “We committed to the product, committed to the benefits it can bring patients. The suggestion that we want to just kick them to the curb is just wrong.”

Another Amylin’ lawyer from Skadden, Arps, Slate, Meagher & Flom disclosed during the hearing that Lilly lost $13.5 million in sales of the new diabetes drug in the first week after Amylin won the temporary restraining order last month, ThomsonReuters reported.

“The court documents emphasize the fact that economic injury alone does not support finding of irreparable harm,” writes ISI Group analyst Mark Schoenebaum in an investor note. “In addition, the court also challenged the assertion over loss of ‘goodwill,’ because FDA prohibits Lilly’s sales reps from making comparative statements between Byetta and Tradjenta without adequate supporting data.”

“We are pleased with the Court’s decision to vacate the temporary restraining order and deny Amylin’s request for a preliminary injunction,” Lilly senior vp and general counsel Bob Armitage says in a statement. “We have complied with our contractual obligations under our agreements with Amylin, and done so in a manner fully consistent with all applicable laws. We believe that Amylin’s allegations against Lilly are entirely without merit and we fully expect to prevail in this litigation.”

gavel pic thx to walknboston on flickr