Last week, the FDA’s
Antimicrobial Advisory Committee drilled deep into evidence on the safety and
effectiveness of Bezlotoxumab, a drug intended to reduce recurrence of C.
difficle infections. The evidence was extensive – slides with data tables and
charts numbered at least 1,855. Half a million Americans suffered from serious
C. diff infections and 29,000 of them died in 2011. Many patients, even after
cured of a C. diff infection have a recurrence (20 to 35%) and those patients
are at 33% higher risk of dying. Preventing C. diff recurrence is a top public
health priority. Bezlo is a new biologic drug intended to reduce the chance of
recurrence when given with antibiotics to cure the initial infection. However
the FDA and committee members voiced serious concerns over whether Bezlo could
interfere with the initial “cure”, which was unexpected, conflicting evidence
between studies of whether there was any improvement in recurrence rates with
Bezlo, and troubling rates of serious adverse events. It is important to note
that C. diff infections are more common in elderly, already fragile patients.
We heard about different definitions of the initial “cure” between the FDA and
Merck, debated why there weren’t fewer deaths in the Bezlo-treated group over
controls, and whether Bezlo could be administered after the initial antibiotic
has already worked to avoid any inference with the cure. While members
generally agreed on the concerns, we split on whether there was “substantial”
evidence of Bezlo’s safety and effectiveness. This was the first time I’ve
voted against a drug’s approval. C. diff recurrence is a serious and deadly problem,
this approach offers great potential, and there was a great deal of support for
the company working on a solution, however many
members felt the evidence wasn’t there yet. The FDA makes the final
decision.
