Amgen's Enbrel in kids "concerning": FDA staff

WASHINGTON (Reuters) - U.S. Food and Drug Administration reviewers are concerned about life-threatening complications in children taking Amgen Inc's drug Enbrel for psoriasis and other conditions, according to agency documents released on Monday.

Amgen, which markets the injectable drug with Wyeth, is seeking approval from the FDA to expand sales to children with moderate to severe forms of the skin condition. The drug is already approved as an arthritis treatment in adults and children.

Regardless of whether the regulators approve the new use, FDA staff reviewers recommended the agency strengthen the drug's label to include reports of serious side effects in children that could lead to deaths or hospitalizations.

The FDA documents were released ahead of a public meeting scheduled on Wednesday to discuss whether to allow marketing of the drug for children with the disease, which can cause painful or itchy patches of red thick skin.

Agency reviewers will present their data to an outside advisory panel at the meeting before panelists make a recommendation. While the agency will make the final decision, it normally follows the advice of its outside experts.

FDA safety reviewers looked at 949 reports of serious complications in children ages 4 to 17 taking Enbrel, or etanercept, for psoriasis as well as arthritis.

Among them, 61 reports were for psoriasis patients, according to the documents. No deaths were reported, but five patients were hospitalized.

Overall, the FDA found 14 deaths and 76 other life-threatening cases. Complications included serious infections as well as seizures and anemia.

"Given that the drug usage in pediatric population is estimated to be fairly small at this time, the numbers and types of post-marketing adverse events reported are concerning," the reviewers wrote.

Safety issues already hang over Enbrel, which carries a strong warning about potentially fatal infections.

The FDA also is investigating whether Enbrel, along with rival products Johnson & Johnson's Remicade and Abbott Laboratories Inc's Humira, are linked to cancer in children.

The big-selling drugs are types of TNF blockers, which suppress the immune system by blocking the tumor necrosis factor (TNF) chemical that can cause inflammation.

FDA reviewers found seven cases of cancer in children taking Enbrel, and two cases were reported in an Amgen study, according to the documents released on Monday.

While Enbrel is not cleared to treat psoriasis in children, doctors are allowed to prescribe it as they see fit. FDA-approval for the expanded use would allow the companies to lawfully market the product for such patients.

The FDA's decision is unlikely to boost sales for the drug, which in 2007 saw $3.2 billion in U.S. and Canadian sales for Amgen. Elsewhere it brought in roughly $2 billion for Wyeth.

Michael Severino, Amgen's vice president of global clinical development for inflammation therapeutics that includes Enbrel, said a few thousand children would be eligible for the new use.

"The number's not large. However, the medical need there is substantial, the impact of disease on those children is quite substantial, and we think there's need for new treatment options for them," Severino told Reuters on Friday.

Severino added that the company believed the drug's benefits compared to its risks were favorable.

In midday trading, shares of Amgen were up 5 cents at $44.02 on the Nasdaq, while shares of Wyeth were off 35 cents at $43.07 on the New York Stock Exchange.

(Reporting by Susan Heavey; Editing by Brian Moss)