SILVER SPRING, MarylandThe Oncologic Drugs Advisory Committee
(ODAC) sent the Food and Drug Administration a mixed message in its votes
regarding a new indication for Gliadel Wafer (polifeprosan 20 with carmustine
implant, Guilford Pharmaceuticals).
By a narrow vote, the panel found Gliadel to be safe and effective for
patients with primary malignant glioma, but voted, again by a slim margin, that
the pivotal study for the new indication was "not adequate."
The Gliadel Wafer is a dime-size disc made of a biodegradable polymer that
contains and slowly releases carmustine (BCNU). Up to eight of the wafers are
implanted in a tumor cavity after surgery for brain cancer. It is currently FDA
approved as an adjunct to surgery to prolong survival in patients with
recurrent glioblastoma multiforme for whom surgical resection is indicated.
The company is now seeking approval of Gliadel Wafer "as a treatment to
significantly prolong survival and maintain overall function (as measured by
preservation of Karnofsky performance status) and neurological function in
patients with malignant glioma undergoing primary and/or recurrent surgical
Federal law requires that studies used by the FDA in approving a medication
must be adequate and well controlled. Guilford presented data from two phase
III studies of Gliadel in support of the new indication.
After listening to and discussing presentations by the company and an FDA
medical review team, committee members agreed unanimously that the pivotal
study presented was well controlled, but voted 7 to 6 that the study was not
adequate. Several members gave varying reasons for their nay votes.
Howard Fine, MD, of the National Cancer Institute and a voting consultant to
ODAC, said that he felt the company presented insufficient histologic data. The
absence of these data made it difficult to assess whether the study showed a
benefit for Gliadel in the patients treated.