By Randall Osborne

As it begins a Phase III trial pairing two treatments for relapsed or refractory B cell non-Hodgkin's lymphoma, Idec Pharmaceuticals Inc. filed a registration statement with the Securities and Exchange Commission to offer 2 million shares of common stock.

Based on Wednesday's closing price of $43.50, up $1.687, for San Diego-based Idec's shares (NASDAQ:IDPH), the offering would raise $87 million. After the offering, the company will have about 21.6 million shares outstanding.

If the underwriters — Morgan Stanley & Co., of New York, and NationsBanc Montgomery Securities LLC, of San Francisco — exercise their 15 percent overallotment option, Idec will bring in $13 million more.

The 30-center Phase III trial is studying IDEC-Y2B8, an anti-CD20 murine antibody radiolabeled with the isotope yttrium-90, which targets the CD20 antigen on mature normal and malignant B cells.

On the first day of testing, patients receive a single infusion of Rituxan (Rituximab), the company's monoclonal antibody, followed by tumor imaging with IDEC-In2b8, an indium-labeled version of the company's anti-CD20 antibody.

Seven days later, patients receive a second infusion of Rituxan, followed by the IDEC-Y2B8 therapy.

Rituxan, cleared for marketing last November as a monotherapy for non-Hodgkin's lymphoma, is the first monoclonal antibody approved by the FDA for use against cancer. In the Phase III trial, it is being used to clear the blood of malignant and normal B cells, allowing IDEC-Y2B8 to penetrate the lymphatic system and target its radiation to lymph tumors.

Last October Genentech Inc., of South San Francisco, returned marketing rights to IDEC-Y2B8, citing its "need to focus resources" and the "smaller market opportunity" for the treatment as compared to Rituxan. Idec was nearing enrollment in Phase II trials of the treatment. (See BioWorld Today, Oct. 6, 1997, p. 1.)

In addition to reporting the start of the Phase III study, Idec said the Phase II trials to date have shown an 82 percent response rate (complete and partial response) for patients with low-grade or follicular non-Hodgkin's lymphoma, treated at one of three escalating doses. Adverse effects were mainly hematologic and dose-dependent.

From among those three doses, Idec selected a standard dose for the Phase III trial based on safety and efficacy profiles from the Phase I/II studies. *