By Matthew Willett

IDEC Pharmaceuticals Corp. submitted a biologics license application (BLA) for its radioimmunotherapeutic, Zevalin (ibritumomab tiuxetan), for the treatment of low grade, or follicular, relapsed or refractory CD20-positive B-cell non-Hodgkin's lymphoma (NHL) and rituximab-refractory follicular NHL.

The therapeutic's approval would mark the first time the company has independently brought a compound to market. Although Zevalin is partnered with Berlin-based Schering AG outside the country, IDEC retained rights to the drug in the U.S.

Connie Matsui, IDEC's senior vice president, planning and resource development, told BioWorld Today that Zevalin could be launched in the second half of 2001. Zevalin has been designated a fast-track compound by the FDA.

"Of the greatest significance is that there would be a new drug for NHL patients that's complementary to Rituxan," Matsui said. "From a corporate point of view, this is the first drug IDEC will bring to market independently. We expect to double the size of our current sales force by the time of launch. Currently, we have about 35 people and sometime during the first year of launch we expect that to rise to about 70."

Zevalin, a mouse monoclonal antibody targeted against the CD20 antigen found on normal mature B cells and cancerous B cells and conjugated to a yttrium-90 radioisotope, is administered in conjunction with Rituxan, IDEC's non-radiolabeled chimeric antibody against CD20.

Matsui said the treatment is designed to use Zevalin to attack cancerous cells after a preliminary Rituxan treatment mops up circulating B cells.

"Rituxan is part of the pre-treatment regimen where the patient receives a smaller-than-usual dose of Rituxan to condition the body to receive the Zevalin," Matsui said. "The Rituxan removes the circulating cells from the body so that by the time the radioactive Zevalin is administered ,it can home in to where the tumor is, rather than chase cells through the bloodstream."

In Phase III trials, researchers compared Zevalin to Rituxan, finding a 77 percent response rate in patients who had no response to chemotherapy and an 81 percent response rate in chemotherapy-sensitive patients.

Rituxan, marketed with IDEC in the U.S. by Genentech Inc., of South San Francisco, in November 1997 became the first anticancer monoclonal antibody approved by the FDA.

IDEC's deal with Schering AG for Zevalin marketing outside the U.S. was valued at about $47 million for IDEC, and included an upfront payment of $13 million, $15 million in development funding and another $19.5 million in milestone payments. (See BioWorld Today, June 11, 1999.)

Matsui said the market for Zevalin should be about 25 to 30 percent that of Rituxan, marketed since 1997 as a NHL treatment. U.S. sales of Rituxan in 1999 totaled $263 million.

IDEC announced the BLA submission news after the market closed Wednesday. IDEC's stock (NASDAQ:IDPH) closed up $10 at $206.125.

Matsui said IDEC has no shortage of potential therapeutics, and that need for further production capacity could open new doors for revenue for the company.

"We have four products in clinical development now for autoimmune diseases, and the majority of those are in Phase II or moving into Phase II, so the next one could be any one of those," she said. "Because we're blessed with having as many product candidates as we do, we're committed to building a large-scale manufacturing facility, and as manufacturing capacity becomes more and more scarce for biological drugs, we want to be in a position to serve that much larger a market."