The agency said the injectable drug showed positive results in two comprehensive studies conducted by the company. However, scientists said the drug may require labeling to warn doctors of possible carcinogenic risks.
While Horsham, Penn.-based Centocor did not assess those risks in its application, the FDA said studies in mice suggest the drug could encourage tumor growth. The agency said it would recommend that information be included in the drug's labeling if it is approved.
The FDA will seek input from its panelists next week, though it is not required to follow their advice.
Ustekinumab is part of a new class of drugs that fight psoriasis by targeting two proteins that regulate the body's immune system and are believed to contribute to the disease.
Johnson & Johnson already markets the drug Remicade in the U.S., which is approved to fight psoriasis, rheumatoid arthritis and the intestinal disorder Crohn's Disease. It competes against Abbott Laboratories' Humira and Amgen Inc. and Wyeth's Enbrel.
Earlier this month, the FDA announced it is investigating whether that class of drugs increase the risk of certain cancers in children.
Johnson & Johnson has touted ustekinumab's infrequent dosing - it can be given in as few as four injections per year - as a key advantage over products already on the market. Remicade requires at least six doses annually.
Drugs already on the market also carry risks of serious side effects, including tuberculosis, pneumonia and liver problems, according to their labeling.
