On Tuesday, an FDA advisory panel will review the first new treatment for lupus in decades. And the early indications are that Benlysta, which is being developed by Human Genome Sciences (HGSI), will win an endorsement. At least that’s how some Wall Street analysts are interpreting the FDA briefing documents filed Friday morning, even though the stock is trading down.
If approved, Benlysta is widely expected to become a blockbuster and possibly make Human Genome a takeover target. The drugmaker, by the way, is developing Benlysta with GlaxoSmithKline (NYSE:GSK). But what issues did the FDA raise? The agency noted two large studies demonstrated a statistically significant difference in the number of lupus patients who responded to Benlysta compared with a placebo. But there were reservations: infections and a higher rate of deaths among Benlysta patients than those on placebo. There was also a surprise observation: a risk of suicide among patients.
The FDA reviewers wrote there was a lack of demonstrated efficacy among African-Americans, efficacy varied among different countries and Benlysta had the most helpful effect on organs that may not be the most debilitating. The “data from other endpoints and subgroup analyses were not consistently supportive. In light of this somewhat marginal efficacy, the relative safety profile of the product must be weighed” (see the conclusion section in the briefing documents (pdf)). “If (Benlysta) 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?”
Wall Street analysts says yes. “The moment of truth is… positive overall we believe, since language from the FDA is cautious and mixed (as it usually is in comprehensive briefing tomes), but there is nothing noted that we would not expect to be a fair topic of discussion for a groundbreaking new drug in an extremely difficult disease state,“ wrote Leerink Swann analyst Joseph Schwartz this morning. “We saw no new data that Human Genome has not previously released that looked less positive than what has previously been presented and continue to expect a positive panel vote.”
Adds ISI Group biotech analyst Mark Schoenebaum: “Remember, FDA briefing documents almost always ‘read negative!’ It’s the FDA’s job to act as the ‘prosecution’ and point out any drug’s disadvantages. We don’t see any major surprises in the documents other than a newly identified increased rate of suicide, which we need to study. All the other side effects mentioned (infection, cancer) were widely expected.”
And RW Baird analyst Chris Raymond writes that “while the suicidality data point is news to us (six suicide attempts - all in Benlysta patients out of about 1,700 patients), this patient population is known to be at higher risk for suicide and the trials are 2:1 skewed toward Benlysta patients, making a strong argument for a chance outcome… The facts haven’t changed. Benlysta was filed on two Phase III trials, both of which under Special Protocol Assessment, and met their primary endpoints convincingly.”