An experimental drug from the Johnson & Johnson unit appears effective, but FDA medical reviewers believe the biologic could slightly increase cancer risks.

The agency reviewers indicate that ustekinumab showed positive results in two comprehensive studies, but may require labeling to warn doctors of possible carcinogenic risks. “Long-term use of ustekinumab may lead to increased risk of tumor development in psoriasis patients,” they wrote. Here is the FDA briefing document.

Centocor didn’t assess the risks in its application, and the FDA reviewers wrote that studies in mice suggest the injectable drug could encourage tumor growth. The agency said it would recommend the info is included in any labeling if the med is approved. Here is the Centocor briefing document.

In its application, Centocor suggested a registry serve as an eight-year, observational study to track safety. But the FDA reviewers conclude the idea “may not be the best research design to study long-term safety” because the registry would be voluntary and, as Centocor acknowleged, “registries may not have the ability to evaluate rare events or identify lower relative risks.”