By Randall Osborne

West Coast Editor

Protein Design Labs Inc. (PDL) filed to sell 2.5 million shares of common stock through a public offering that aims to raise $219.9 million.

Fremont, Calif.-based PDL's deals related to humanized monoclonal antibodies have been bearing fruit steadily, with American Home Products Corp. (AHP), of Madison, N.J., most recently commercializing injectable Mylotarg (gemtuzumab ozogamicin), which is the first approved targeted chemotherapy agent using monoclonal antibody technology. (See BioWorld Today, May 22, 2000, p. 1.)

AHP developed the product through a patent licensing deal with PDL, which also signed a multiple patent license agreement earlier this year with Tokyo-based Chugai Pharmaceutical Co. Ltd., netting more than $6 million up front, along with annual maintenance fees and royalties. (See BioWorld Today, May 19, 2000, p. 1.)

In the second quarter, PDL reported somewhat higher-than-expected profits as a result of its antibody payments, earning $5 million on revenues of $20.4 million.

Although exact details of such arrangements are seldom disclosed, the licensing fee typically works out to about $1 million, with annual maintenance fees and royalties in the range of 3 to 4 percent.

The company gets royalty revenue from sales of Synagis (palivizumab) from MedImmune Inc., of Gaithersburg, Md.; Herceptin (trastuzumab) from South San Francisco-based Genentech Inc.; and Zenapax (daclizumab), created by PDL and licensed to Hoffmann-La Roche Inc., of Nutley, N.J.

PDL, which aims to use the money from the offering for clinical trials, sales and marketing, working capital and for other corporate purposes, has more antibodies under development for autoimmune and inflammatory conditions, transplantation, cancer and other conditions.

After the offering, PDL would have 42.3 million shares outstanding.

Co-managers of the offering, which includes 375,000 more shares for overallotments, are CS First Boston, CIBC World Markets and SG Cowen.

PDL's stock (NASDAQ:PDLI) closed Wednesday at $86.375, down 5 percent.