Washington Editor

IDEC Pharmaceuticals Corp.'s stock dipped Tuesday on news that the company voluntarily stopped clinical trials of its anti-CD40 ligand monoclonal antibody, IDEC-131, after one patient developed a blood clot in the lower leg.

The company's stock (NASDAQ:IDPH) closed Tuesday at $32.03, down $6.34, or 16.52 percent.

Also, it is likely that the trading price was affected by IDEC's disclosure that Medicare will not commence reimbursement of Zevalin until Oct. 1, a three-month delay. In February, the FDA approved Zevalin for use in non-Hodgkin's lymphoma patients. (See BioWorld Today, Feb. 21, 2002.)

But the more pressing issue relates to IDEC-131, a drug being studied in three Phase II trials in patients with idiopathic thrombocytopenia purpura (ITP), Crohn's disease, psoriasis and multiple sclerosis.

In a conference call with analysts and reporters after the market closed Monday, Paul Grint, chief medical officer of San Diego-based IDEC, said the company was notified last week that one patient suffering from severe Crohn's disease who had received an infusion of IDEC-131 had developed a blood clot on a lower limb. To date, just over 200 patients have been treated with the drug, and this case represents the only such problem, he said.

"In the interest of patient safety, we took immediate action to halt all investigational studies and we quickly informed the clinical investigators participating with us," Grint said. "We have had discussions with the medical reviewers at the FDA and have agreed that our investigational new drug applications on these studies should be placed on clinical hold pending a detailed evaluation of this safety issue."

Furthermore, he said, it is too early to determine how this event will affect the development of IDEC-131. "We have limited information at this time and, to protect patient confidentiality, it is not appropriate to discuss more details at this time," he said.

Phase II studies of IDEC-131 began in 1999, the same year that Cambridge, Mass.-based Biogen Inc. stopped Phase II trials of its humanized anti-CD40 ligand antibody called Antova because of thromboembolic events. Biogen had hoped Antova could be used for several indications including Factor VIII inhibitor syndrome, islet cell transplantation, multiple sclerosis and lupus. (See BioWorld Today, Oct. 25, 1999.)

Vince Reardon, IDEC's director of corporate communications, told BioWorld Today that the company expects to have a better understanding within the next three to four weeks of how and why this patient developed a blood clot.

"This is the first blood clot we've seen, so we are going back and looking at the other folks that we've treated to see if we might have missed something," he said. "We are conducting an investigation into the patient's condition now, and hopefully we will have something to share with the Street in the second-quarter conference call."

IDEC is developing IDEC-131 on its own, but is partnered in Europe and Asia with Japan-based Eisai Co. Ltd.

Meanwhile, IDEC is trying to determine why its Medicare reimbursement code for Zevalin has been delayed by the Centers for Medicare and Medicaid Services (CMS).

"In our approval notification, CMS cited time constraints and systems issues' as the reason for the delay, and we will be trying to gain clarity on these issues during the coming days," William Rohn, IDEC's president and chief operating officer, told listeners during the conference call. "There's no doubt that a lack of an effective Medicare reimbursement code has presented a hurdle to widespread adoption of the Zevalin therapeutic regimen to date. While over 325 administration sites are properly licensed and trained to dose Zevalin, many institutions have chosen to hold off giving Zevalin to any patients until the Medicare reimbursement situation has been clarified."

Zevalin, a radioimmunotherapy, is indicated for the treatment of relapsed or refractory low-grade, follicular, or transformed B-cell non-Hodgkin's lymphoma (NHL) including patients with Rituxan (rituximab)-refractory follicular NHL.

Pending the reimbursement code, Medicare will pay 78 percent of the average wholesale price of the drug regimen, Reardon said. IDEC partnered Zevalin with Schering AG, of Berlin, for sales outside the U.S. The worldwide market for the product could reach as high as $1.6 billion annually. (See BioWorld Today, Feb. 21, 2002.)