By Lisa Seachrist

Washington Editor

After hitting a regulatory snag last summer, Aronex Pharmaceuticals Inc. has submitted additional data to the FDA on the company's cancer drug, Atragen.

The move, in the form of an amendment to the December 1998 new drug application (NDA) for Atragen, puts the drug under a 12-month review period at FDA. Aronex has filed for the right to market Atragen as a therapy for acute promyelocytic leukemia (APL) in patients who require an intravenous administration of drug.

"We're very excited about this filing," said Connie Stout, director, corporate communications for The Woodlands, Texas-based company. "We're happy to see this move forward."

The company's stock (NASDAQ:ARNX) closed Thursday at $3.093, down 3 cents on the news.

The NDA filing for Atragen ran into trouble last August when the FDA informed the company the Oncologic Drugs Advisory Committee wouldn't consider the drug at its Sept. 17, 1999, meeting because there were deficiencies in the NDA. The news of that decision sent the company's stock plummeting from $6.937 to $4.50, or 35 percent. (See BioWorld Today, Aug. 6, 1999, p. 1.)

At that time, the agency didn't detail the problems with the NDA. The FDA informed the company of the specific issues in the form of a non-approvable letter in September. That letter deflated Aronex's stock by another 20 percent to close at $3.687. (See BioWorld Today, Sept. 27, 1999, p.1.)

Stout said the company conducted a series of meetings with the FDA to ensure the amendment satisfied reviewers' concerns.

"We believe we've answered their questions," Stout said. "Basically, we are now under a standard review."

Atragen, a vitamin A derivative, is an injectable liposomal formulation of all-trans retinoic acid (tretinoin). Atragen works by inducing cell differentiation and, eventually, apoptosis. It can be used in combination with chemotherapy regimens.

The amendment to the NDA includes additional safety and efficacy data in the proposed indication from patients enrolled in the clinical study after the 1998 NDA filing. It includes data on 116 APL patients, whereas the original NDA included only 59 patients.

In addition to APL, Aronex is conducting Phase II clinical trials to evaluate the potential of the product as a treatment for non-Hodgkin's lymphoma, hormone-resistant prostate cancer, and acute myelogenous leukemia. The company has a Phase I/II program of the drug in combination with interferon alpha as a treatment for renal cell carcinoma.

Aronex's second product, Nyotran, is an injectable liposomal formulation of nystatin for treating fungal infections. In February, the drug failed to meet its primary endpoint in a Phase III study in patients with cryptococcal meningitis. (See BioWorld Today, Feb. 17, 2000, p. 1.)

Stout said the company has been in discussion with the FDA about Nyotran, and has plans to submit an NDA for the drug; however, the company hasn't released its timetable for such a submission.