BRISTOL-MYERS SQUIBB’s VUMON CANCER THERAPY APPROVED JULY 14

BRISTOL-MYERS SQUIBB's VUMON CANCER THERAPY APPROVED JULY 14 for the treatment of refractory childhood acute lymphoblastic leukemia (ALL) in combination with other anticancer drugs. Bristol-Myers Squibb originally sought approval of Vumon (teniposide) for treatment of multiple indications of ALL, but FDA's Oncologic Drugs Advisory Committee outright rejected two of the indications, as well as narrowly rejecting an indication for refractory childhood ALL ("The Pink Sheet" July 8, 1991, T&G-5). In response to an FDA request to reanalyze its data, late in 1991 BMS submitted data demonstrating patients' refractoriness to prior therapy and their subsequent responses to teniposide. "We have completed the review...and have concluded that adequate information has been presented to demonstrate that Vumon is safe and effective for induction therapy in patients with refractory childhood acute lymphoblastic leukemias when used in combination with other approved anticancer agents," FDA Oncology and Pulmonary Drug Division Acting Director Gregory Burke, MD, said in the drug's July 14 approval letter. Vumon, which had a priority review status and took 21-1/2 months to be approved, will be available in 50 mg (5 ml) ampules. The therapy is administered by intravenous infusion lasting 30-60 minutes; patients remain under continuous observation for the first hour of administration and at intervals thereafter. A draft of the product's labeling notes that "blood counts as well as renal and hepatic function tests should be carefully monitored prior to and during therapy." The drug is contraindicated in patients who have had previous hypersensitivity to teniposide and/or polyoxyethylated castor oil. "Physicians should be aware of the possible occurrence of a hypersensitivity reaction variably manifested by chills, fever, urticaria, tachycardia, bronchospasm, dyspnea, hypertension or hypotension and facial flushing," the labeling warns. "This reaction may occur with the first dose of Vumon and may be life threatening if not treated promptly with antihistamines, corticosteroids, epinephrine, intravenous fluids and other supportive measures as clinically indicated." Labeling for the drug states that it has a broad spectrum of in vivo antitumor activity against murine tumors, including hematologic malignancies and some solid tumors. The drug is also active against sublines of certain murine leukemias with acquired resistance to cisplatin, doxorubicin, amsacrine, daunorubicin, mitoxantrone or vincristine. In a clinical study conducted at St. Jude Children's Research Hospital in Memphis, nine children with acute lymphocytic leukemia who did not respond to a cytarabine-containing regimen were treated with Vumon and cytarabine. Complete remission occurred in three of the patients for 30 weeks, 59 weeks and 13 years. In another study, 16 children who also failed previous treatments were administered Vumon plus vincristine and prednisone. Complete remission in this study occurred in three patients for durations of 5.5, 37 and 73 weeks. Teniposide has been available under a Treatment IND since October 1988 for treatment of relapsed or refractory acute lymphoblastic leukemia. BMS said patients in the Treatment IND program will continue to get the drug at no cost. The price to wholesalers is $115.68 per ampule. The drug has been available in Europe since the 1970s and also is approved in Canada. In 1981, FDA rejected Bristol's NDA for teniposide in treating refractory bone cancers.