By Mary Welch

Immunex Corp. and its partner, Ivax Corp., said the FDA has confirmed that their abbreviated new drug application (ANDA) for paclitaxel by injection is the first for a generic Taxol product to be submitted for marketing approval.

This "first" status is important because, following FDA approval, it will give the companies' anticancer formulation exclusive shared marketing with Bristol-Myers Squibb Co.'s Taxol for 180 days before other generic forms of the cancer treatment can be sold.

Immunex, of Seattle, filed the ANDA in August 1997. It was accepted for filing in October 1997. Ivax, of Miami, also filed an ANDA for its generic version of Taxol, but the two companies decided to collaborate in June 1998, after it was determined Immunex was first to file for FDA approval. As part of the agreement, Ivax acquired the Immunex ANDA and its bulk inventories of paclitaxel for an undisclosed cash payment. Ivax also will pay Immunex royalties based on net sales of the drug.

Being the first to file an ANDA is only one hurdle in bringing a generic drug to market. The company may face a court challenge from the firm holding patents on the brand-name product. If a lawsuit is filed, the FDA cannot rule on the ANDA until the litigation is concluded or 30 months have passed, whichever comes first.

With its December 1992 FDA approval of Taxol, Bristol-Myers, of New York, received five years' marketing exclusivity under provisions of the Waxman-Hatch Act.

The law also gave Bristol-Myers another two-and-a-half years of exclusivity to defend its position against any patent violations. This period started in December 1997 and ends June 2000.

Litigation Holds Up FDA Action

Bristol-Myers is contesting the assertion that the Immunex-Ivax ANDA does not infringe its Taxol patents. The pharmaceutical company filed suit against Immunex and Ivax in late 1997 in U.S. District Court in Newark, N.J.

Ivax filed a counterclaim to invalidate the patents and also asserted that Bristol-Myers is in violation of federal antitrust and unfair competition laws.

The suits currently are in the discovery phase of the legal process. As part of the agreement, Ivax will oversee these lawsuits, with Immunex reimbursing Ivax for a percentage of the litigation costs.

Bristol-Myers had no comment on the court case or the paclitaxel ANDA.

"We believe we have a solid basis for invalidating their patents," said Robert Jaffe, director of corporate communications for Ivax.

"Say it is now June 2000," said Cathy Keck Anderson, communications consultant for Immunex. "The FDA can approve our application for breast and ovarian cancer and we can market our generic version of Taxol — even if the litigation is not over. But then we have a business decision and do a lovely dance. Do we risk marketing our drug and possibly lose in court, or do we wait until everything is resolved?"

Discovered by researchers at the National Cancer Institute, Taxol itself is not patentable, but the means of delivering it and the dosage regime are patentable. Taxol is approved for breast and ovarian cancer and Bristol-Myers is seeking to expand the label.

The stakes are high. Taxol sales reached $304 million for the second quarter of 1998; $200 million of that was from the U.S. market. Sales for 1997 were $940 million and the drug likely will break the $1 billion mark this year.

If all goes well for the Immunex-Ivax ANDA, the generic version will go one-on-one with Taxol before any other competitors.

"After the 180 days, the flood gates are open. The dam is broken," Anderson said. "All we're trying to do is give alternatives to women, doctors and insurance companies so they can have access to this important drug."

Ivax's stock (AMEX:IVX) closed Thursday at $9.062, up $0.375.

Immunex's stock (NASDAQ:IMNX) closed Thursday at $63.50, down $0.50. *