By Mary Welch

Aronex Pharmaceuticals Inc. received $5.6 million from Abbott Laboratories for achieving two milestones as Nyotran, an injectable liposomal formulation of nystatin, progresses through Phase III trials for patients with presumed fungal infections.

Aronex, of The Woodlands, Texas, has collected milestone payments of $8.4 million from Abbott, along with an additional $3 million related to a stock purchase agreement. The companies launched the Nyotran collaboration in November 1998.

The latest milestones reflect completion of patient enrollment and treatment required under the protocol for Phase III comparative multicenter trials of Nyotran against amphotericin B in patients in Europe and the U.S. The study involved 250 sites and more than 500 immunocompromised cancer patients.

"It involved an extensive group of patients in a blind, comparative trial," said Connie Stout, associate director of corporate communications for Aronex. "It will take us a while to gather the data. Our goal is to submit an NDA (new drug application) in mid-1999. We expect to hopefully be able to talk about the results in the same time frame."

Nystatin, a traditional anti-fungal therapy, is used only for topical infections. It belongs to a class of drugs known as polyene derivatives, which include amphotericin B, the standard treatment for systemic fungal infections.

Aronex said its liposomal version of the drug has a low toxicity profile, allowing for systemic administration - a potential advantage over other formulations.

Drug Now In Three Trials, Including Two Phase IIIs

Nyotran is actually in three clinical trials, two of which are in the Phase III stage. In the other Phase III trial Nyotran's efficacy is being evaluated against Cryptococcal meningitis. It is also in Phase II to test it in an Aspergillus salvage indication, a mold-based infection.

Aronex already has completed a Phase II trial evaluating Nyotran in patients with life-threatening Candida (yeast-based) infections. Preliminary data showed that of the first 75 patients enrolled, 67 percent were successfully treated with Nyotran.

"We have had some physicians ask us to continue that trial because they had some refractory patients who needed it," Stout said. "So we are still recruiting and we may use the data in our NDA filing. If you are to ask if we will take it into a Phase III trial, I'll have to say I don't know the answer."

The company expects Nyotran to enter Phase III trials for the Aspergillus salvage indication sometime this year, with an NDA filing for an indication against Cryptococcal meningitis expected in 1999.

"We are not sure what the label claims will be," Stout said. "Of course, we will have to see what the data says. The preferred indication is 'label of choice.'"

Stout declined to disclose what future milestones are or how much Aronex will receive.

In November, Aronex and Abbott Laboratories, of Abbott Park, Ill., signed an up-to-$40 million deal for exclusive worldwide rights to Nyotran. Abbott made a $2.85 million up-front payment and purchased 837,989 shares of Aronex's common stock for $3 million. Abbott will be responsible for marketing Nyotran upon FDA approval, and has an option to manufacture the drug. Aronex retains the opportunity to co-promote Nyotran within the U.S. and Canada for at least two years.

Aronex's stock (NASDAQ:ARNX) closed Monday at $2, up $0.062. n

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