Amgen's Blockbuster Gets Cold Shoulder

An FDA advisory panel took another whack at Amgen last week after voting overwhelmingly for more restrictions on the company's top seller, anti-anemia drug Aranesp (darbepoetin alfa).

Committee members called the meeting to determine whether Aranesp--and its competitor red-blood-cell booster, J&J's Procrit (epoetin alfa)--can raise the risk of death in cancer patients. Earlier this year, both companies added black-box labels that warn of an increased risk of blood clots and tumor progression, particularly at high doses.

Calling the panel "very hostile," Les Funtleyder, an analyst at Miller Tabak, said that Amgen will need a turnaround plan once new prescribing guidelines cut into the blockbuster's sales, which accounted for nearly 30 percent of the biotech's revenue in 2006. "When an FDA panel member wonders aloud whether a company drug is 'killing people,' that company has a safety issue (real or perceived) to deal with," Funtleyder wrote in a research note.

Aranesp had worldwide sales of $1.02 billion in the first quarter of this year, a 14 percent increase over the same period last year. But already the company noted that US growth has slowed since FDA required new labeling information in March. Procrit had worldwide sales of $817 million last quarter, a 4 percent increase over the same time last year.

Yaron Weber, an analyst at Citigroup, observed in a research note that the panel's recommendations could influence not only oncologists but also nephrologists, who prescribe the drug to increase red blood cells in patients with chronic renal failure. He added that payers might move to limit reimbursement, and predicted "potential widespread erosion in the use of EPO drugs."

The Oncologic Drug Advisory Committee voted 17-0 Thursday for further study--preferably a large, simple trial comparing survival rates of patients who take the drugs with those who do not--and 15-2 for stricter prescribing guidelines on Erythropoiesis-stimulating agents (ESAs) like Aranesp and Procrit. Although these restrictions were still being hashed out at press time, the panel voted against recommending lower dosing levels.

The vote might also influence FDA's decision to approve Roche's Micera, another ESA under review, according to Funtleyder.

Amgen, for its part, gave its best shot at defending the safety of its blockbuster. In an information packet prepared for the meeting, it reminded the committee that preclinical data was "reassuring" in terms of Aranesp's effect on patient survival and tumor growth. It also noted that the four studies that show adverse effects "address experimental, unapproved indications." And it further stated that blood transfusions, which ESAs hope to forestall, carry their own risks--like infection and immunosuppression.

Analysts in turn took their own whacks at Amgen stock, hacking away at revenue estimates on the assumption that the FDA would follow its advisors' lead. And the biotech may be in for further bruising in the fall, when the agency plans to meet on the use of Aranesp in kidney patients. But at least one analyst, Chris Raymond at Robert Baird, noted that FDA would likely await results from further studies before requiring any more sweeping labeling changes.