Washington Editor

Abgenix Inc.’s stock took a small hit Friday following the disclosure that a Phase IIa study of its rheumatoid arthritis candidate failed to meet its endpoints.

Thus the company, based in Fremont, Calif., has abandoned plans to further study ABX-IL8 in rheumatoid arthritis (RA). ABX-IL8, a monoclonal antibody generated with Abgenix’s XenoMouse technology, blocks interleukin-8, a chemokine found in several diseases.

The company’s stock (NASDAQ:ABGX) closed Friday at $29.70, down $1.98, or 6.3 percent.

“We are disappointed with the results of this clinical trial, which we feel has shown some activity in terms of anti-inflammatory activity,” Gisela Schwab, Abgenix’s vice president of clinical development, told BioWorld Today. “But the magnitude is not sufficient to take ABX-IL8 forward in RA.”

Even though ABX-IL8 didn’t appear to significantly reduce swollen joint counts in RA patients, or have a great impact on tender joint counts and pain, Abgenix and Wall Street haven’t lost faith in the drug.

“Obviously, we are disappointed that one of their programs has failed, but the beauty of the Abgenix business model is that they have multiple products in the clinic for multiple indications,” Michael King, managing director and senior biotechnology analyst at Robertson Stephens Inc. in New York, told BioWorld Today. “Abgenix is not a single-product company that will die if they fail in their first attempt at proving a product works.”

Indeed, the RA indication is just one of several Abgenix has earmarked for the interleukin-8 blocker. Phase IIa studies of ABX-IL8 in psoriasis patients showed a reduction in skin scores over three months. And at the end of 2001, the company completed enrollment in Phase IIb studies in moderate-to-severe plaque psoriasis patients. Also, Abgenix has initiated enrollment of a Phase IIa study in chronic obstructive pulmonary disease.

Thomas Dietz, an analyst with Pacific Growth Equities Inc. in San Francisco, who has a “strong buy” rating on Abgenix, released research notes saying data indicate that ABX-IL8 has activity in the disease state, suggesting that failure of the RA trial may be more due to the role of IL-8 in RA than the potency of ABX-IL8 as an anti-IL-8 therapy.

In the RA study, ABX-IL8 appeared safe and well tolerated, an Abgenix statement said. Furthermore, the company said adverse events were similar in both treatment groups, and no human anti-human antibodies were detected. The double-blind, placebo-controlled, randomized study evaluated 153 RA patients at 23 U.S. sites.

“We have to admire that Abgenix has decided to put a bullet in it [the RA program],” King said. “A lot of companies would try to create something out of nothing and move forward, and 99 times out of 100 when companies do that, it turns out to be a failure. I think they made a prudent decision here.”

Schwab agreed with King’s statement, saying, “We want to run proper studies, good studies that give us an answer early, before we spend lots of money nurturing something that doesn’t merit being nurtured. We designed studies such as this one, and empowered them sufficiently so that we would get an answer does it work or does it not work?”

The negative news surrounding RA comes on the heels of recent positive updates on Abgenix’s lead cancer molecule known as ABX-EGF.

Shortly before release of the RA study, Abgenix sent out a statement saying it initiated a Phase II clinical trial of ABX-EGF in prostate cancer patients. ABX-EGF, also developed with the XenoMouse technology, is a fully human monoclonal antibody that targets the epidermal growth factor receptor, a receptor that lies on the outer surface of many cells. The receptor is overexpressed in most common human tumor types.

Abgenix is studying ABX-EGF in conjunction with partner Immunex Corp., of Seattle (Immunex is being purchased by Thousand Oaks, Calif.-based Amgen Inc.). Aside from the prostate cancer indication, the molecule is being tested in kidney cancer, non-small-cell lung cancer, and in metastatic colorectal cancer patients who have failed chemotherapy. The Immunex-Abgenix agreement calls for Abgenix to initiate studies in a total of five indications. The final indication is expected to be announced later this year. (See BioWorld Today, Dec. 31, 2001, and Nov. 29, 2000.)

The prostate cancer study will enroll up to 50 patients who will receive intravenous infusions each week, over an eight-week treatment cycle, for up to five cycles. The primary efficacy endpoint will be measured by prostate-specific antigen response rates.

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