WASHINGTON, D.C. (
) --U.S. regulators posed some tough questions about the efficacy and safety of
Human Genome Sciences'
experimental lupus drug Benlysta in a review posted ahead of next Tuesday's advisory panel meeting.
Investors largely expect Human Genome Sciences and partner
to receive approval for Benlysta, which would be the first new treatment for the autoimmune disease lupus in about 50 years. To achieve the goal, however, Benlysta must first pass muster from a panel of outside experts and then receive final approval from the U.S. Food and Drug Administration.
Friday's medical review of Benlysta
, posted on the FDA's web site, is the first step in this process. The FDA tends to take a prosecutorial role in its drug reviews ahead of advisory panel meeting, so investors largely anticipated the questions and concerns raised about Benlysta.
Across two large clinical trials, FDA acknowledged that two large clinical trials demonstrated a statistically significant difference in the number of lupus patients who responded to treatment with Benlysta compared to placebo. However, FDA said the results from the Benlysta studies produced "somewhat marginal efficacy" in part because the drug's biggest positive effect was on organ systems in patients that are not life threatening. The FDA also found that the study conducted outside the U.S. also produced stronger results than the study conducted here and African-Americans lupus patients underperformed relative to non-African Americans.
The FDA also raised some concerns about Benlysta's safety, including risk for infections and neuropsychiatric adverse events including suicide. The specter of an increased risk of suicide was probably the most surprising revelation in the FDA material.
"Clearly there is a need for effective therapies in SLE
lupus," FDA concludes. "However whether belimumab's
Benlysta's benefits sufficiently outweigh its risks is the crux of the issue... If belimumab only has a modest effect for some patients and manifestations, is a possible increased risk of death, infection, or neuropsychiatric adverse effects worth the potential benefit?"
That's the question which will be answered Tuesday when the FDA's panel of outside experts convene and decide whether to recommend Benlysta for approval, or not.
"Overall, we still think the panel is likely to vote for approval and see nothing in here surprising, other than suicide," said ISI Group biotech analyst Mark Schoenebaum, in an Friday email to clients. "Of course, panels are -- in the end -- impossible to predict. But we are sticking with this one and would recommend adding to positions on what is likely to be a bit of weakness this morning after the stock's recent run."
Human Genome shares dipped about 5% in early trading but are now down 1% to $26.14. The stock closed Thursday at $26.48.
Lupus is a chronic disease in which the body's immune system creates auto-antibodies that attack connective tissue, resulting in inflammation and tissue damage, often to the heart, joints, lungs and kidneys. Women are more often diagnosed with lupus than men, and the disease goes through periods where it flares up then goes into remission.
Benlysta is a human monoclonal antibody designed to recognize and tamp down the biological activity of B-lymphocyte stimulator, or BLyS, a substance that was discovered by Human Genome. High levels of BLyS plays a role in the development of abnormal B cells (B cells are a component of the immune system), and abnormal B cells lead to increased auto-antibody formation.
Benlysta appears to lower levels of BLyS and therefore stop young B cells from growing abnormally. One advantage to treating lupus with this approach is that Benlysta doesn't appear to affect more mature B cells, which are an important part of a patient's immune system.
--Written by Adam Feuerstein in Boston.
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