By Randall Osborne

West Coast Editor

The mouse roared.

Less than two weeks after Abgenix Inc. filed to raise about $273 million through the sale of 1.8 million shares, the company - which uses its XenoMouse technology to create fully human antibodies - raised a whopping $630 million by selling 3 million shares.

If underwriters exercise their option to buy 450,000 shares in overallotments at the price of $210 per share, the amount raised will jump to $724.5 million.

The follow-on offering is second in size in biotech only to Roche Holding Ltd.'s $3 billion offering of South San Francisco-based Genentech Inc.'s stock in October, which followed the historic $2.1 billion Genentech IPO in July. (See BioWorld Today, July 21, 1999, p. 1.)

Abgenix sold 2.16 million of the shares in the offering, and shareholder Cell Genesys Inc. sold 840,000. Of the overallotments, Abgenix, of Fremont, Calif., would sell 324,000 and Cell Genesys the remainder. With the stock sale, Foster City, Calif.-based Cell Genesys owns about 13.3 percent of Abgenix, which now has 19.3 million shares outstanding.

Kurt Leutzinger, vice president and chief financial officer of Abgenix, said he could not comment because of the SEC "quiet period" rule.

Peter Ginsberg, an analyst with U.S. Bancorp Piper Jaffray in Minneapolis, said big pharmaceutical firms are trying to beef up their pipelines by using every approach at once, and antibody companies are among the beneficiaries.

"It's a way of vertically integrating," he said. "Having the genes and knowing what they do is important, and developing a product is important. Antibody companies are the last phase."

Ginsberg said genomics companies, biotech firms with anticancer drugs, and human antibody developers such as Abgenix, Medarex Inc., of Annandale, N.J., and Protein Design Labs Inc., of Fremont, Calif., are pockets of the industry that have performed extremely well. "They're the ones I keep coming back to," he said.

Abgenix's stock (NASDAQ:ABGX) has been leaping for months. In June, it was trading at about $15, and it closed Friday at $225, up $7.937. In December, news of collaborations, plus the move of the company's ABL-CBL monoclonal antibody into Phase III trials, and the acquisition of XenoMouse from Tokyo-based Japan Tobacco Inc. pushed the stock price from $60.125 in the first week to $112 later that month.

The success of Abgenix quashed a merger between Cell Genesys and Genzyme General. Late last year, with Abgenix's stock price up to $112, Cell Genesys said it was backing out of the $350 million, stock-for-stock Genzyme deal, noting the value of Cell Genesys' equity ownership in Abgenix had increased by more than $230 million since the merger agreement was made public in the fall. (See BioWorld Today, Oct. 19, 1999, p. 1.)

At the same time, Abgenix made public its plan to pay $47 million to acquire Japan Tobacco's share in the XenoMouse technology and another $10 million for Japan Tobacco to relinquish its option and license rights. Earlier that month, Abgenix also signed its largest XenoMouse collaboration, with Human Genome Sciences Inc., of Rockville, Md. (See BioWorld Today, Dec. 2, 1999, p. 1; and Dec. 22, 1999, p. 1.)

Most recent among the XenoMouse pacts is a deal with Gliatech Inc., of Cleveland, in January, to generate fully human monoclonal antibodies to the complement protein properdin for use in the fields of cardiovascular and inflammatory diseases. Abgenix will receive a technology access payment and could receive additional fees, milestone payments and royalties.

Proceeds from the current offering will go toward building a manufacturing facility, funding clinical trials and possibly acquiring other firms. Abgenix has four antibody product candidates under internal development, three of which are in human trials.

Those three candidates are: ABL-CBL, ABX-IL8, and ABX-EGF. ABL-CBL is in Phase III trials for steroid-resistant graft-vs.-host disease. ABX-CBL is a monoclonal antibody that binds to the protein CD147, which is up-regulated on certain activated immune cells. It attaches to the CD147 antigen, and signals other immune cells to destroy the targeted cell. (See BioWorld Today, Dec. 9, 1999, p. 1.)

ABX-IL8 is in Phase I/II trials for psoriasis, and ABX-EGF is in Phase I for various epidermal growth factor receptor-dependent cancers.

The shares in the current financing were offered by an underwriting group led by Robertson Stephens, Lehman Brothers Inc., Merrill Lynch & Co. and Pacific Growth Equities Inc.