BRISTOL's TENIPOSIDE REFRACTORY ACUTE LEUKEMIA INDICATION REJECTED

BRISTOL's TENIPOSIDE REFRACTORY ACUTE LEUKEMIA INDICATION REJECTED by FDA's Oncologic Drugs Advisory committee at its July 1 meeting. The committee narrowly rejected the NDA for the chemotherapy agent as a treatment for refractory childhood acute lymphocytic leukemia. The NDA for teniposide, also known as VM-26, was filed in September 1990. Bristol-Myers Squibb was seeking approval for multiple indications in ALL patients: consolidation for patients who begin to fail after induction of remission; induction of response in children who failed primary induction with another chemotherapeutic drug; and multiple relapses or refractory disease. The committee voted unanimously against the consolidation indication and 7-to-2 against the multiple relapse claim but came close to supporting an indication in children failing primary induction, with a vote of 4 in favor, 5 against. FDA outside expert reviewer David Tubergen, MD, Denver Children's Hospital, noted that children who failed to respond with any remission to primary induction were becoming rare due to advances in therapy. However, the prognosis for those cases that do occur is "disastrous," he said, making addition of any new agents attractive for this indication. However, committee member Steve Piantadosi, MD, Johns Hopkins University, found that "the data was not there" to show efficacy. Bristol presented data from 110 ALL patients over a 15-year period who were treated experimentally with teniposide. The committee found it difficult to determine the extent of the anti- cancer drug's specific benefit to patients since teniposide has been used in combination with other chemotherapy drugs, including ara-c and combination vincristine and prednisone. "The precise role for VM-26 as a single agent in the drug armamentarium cannot be determined" from the data presented, Tubergen concluded. The length of the research period also presented a problem in determining teniposide's efficacy since the therapy regimens in which VM-26 was combined and those which were used as controls in the early years of the studies are no longer standard therapies for ALL. Committee debate also centered on whether definitions of refractory and resistant disease clearly had been established in the studies. Office of Drug Evaluation I Director Robert Temple, MD, told the committee that the agency will consider asking the company to re-analyze its data on teniposide to meet the committee's concerns. A 1981 teniposide NDA for treatment of refractory bone cancers previously was turned down by the agency. The product has been available to ALL patients under a Treatment IND protocol since September 1988 and has been designated a Group C drug by NCI. The drug has been approved for use in Europe since the 1970s and is now approved in Canada, Bristol said.