BURROUGHS WELLCOME’s LAMICTAL ANTICONVULSANT WILL GET FDA REVIEW

BURROUGHS WELLCOME's LAMICTAL ANTICONVULSANT WILL GET FDA REVIEW by the agency's Peripheral & Central Nervous System Drugs Advisory Committee "during the first quarter of 1993," Burroughs Wellcome President and CEO Philip Tracy told a Dec. 2 session of the Mabon Securities Research Conference in New York City. Tracy said that Lamictal (lamotrigine) will be reviewed by the advisory committee "for use as add-on therapy for partial seizures." Outlining advantages of the anticonvulsant compound, Tracy pointed out that Lamictal has a less complicated dosing regimen than other drugs of its type. "Unlike other compounds under study, Lamictal does not require dosage alterations of coadministered drug," the Burroughs Wellcome exec stated. "Rather, the dosing level of Lamictal can be adjusted to complement the patient's existing therapy." Lamictal is already on the market in the U.K. and Ireland, where Tracy said it has "done quite well." A Burroughs Wellcome "fact sheet" on Lamictal explains that the anti-epileptic drug has been studied in over 900 patients and volunteers in the U.S. More than 400 patients have completed at least one year of treatment for approximately 1,000 patient years of treatment experience. In two double-blind, placebo-controlled studies conducted at several U.S. centers, "doses of up to 500 mg/day [of Lamictal] were added to each patient's...regimen." "Nearly 75% of the patients responded favorably to the addition of lamotrigine, [with] half of the total patients experiencing a reduction in partial seizure frequency of greater than 25%, and a quarter of them experiencing at least a 50% reduction," the fact sheet states. Lamictal "is generally well tolerated," with approximately 7% of drug patients in clinical trials discontinuing treatment due to adverse experience, compared to 3% of placebo patients, the fact sheet says. Commonly observed adverse experiences associated with the use of add-on therapy with Lamictal in more than 2,500 patients "and not seen at a similar incidence among placebo- treated patients" included: dizziness, ataxia, somnolence, headache, blurred vision, nausea and rash. Adverse incidents were "generally mild, observed within the first two weeks of therapy and resolved without countermeasures or discontinuation of therapy," Burroughs said. Including Lamictal, Tracy said that Burroughs Wellcome has "some 39 projects between preclinical and Phase IV [postmarketing trials] that are under active review" by FDA, "cutting across all of our key therapeutic areas." Another of these drugs is Flolan (esoprostenol sodium or prostacyclin), which Burroughs Wellcome is "initially" pursuing for the treatment of primary pulmonary hypertension, an orphan indication. Flolan also is being studied for the treatment of congestive heart failure, Tracy noted, with preliminary data indicating "that the compound may well be effective in Class III and Class IV [congestive] heart failure." Flolan's use as a replacement for heparin in hemodialysis has been pending since 1986. Acrivastine, a nonsedating antihistamine, is another Burroughs Wellcome drug in the late stages of development. "Its therapeutic index and fast onset of action will offer distinct advantages over other antihistamine products that are currently on the market," Tracy said. Acrivastine has been reported in Phase III. The company also has submitted an NDA for an acrivastine/pseudoephedrine combination for treatment of allergic rhinitis and urticaria. Referring to reports of cardiotoxicity associated with Marion Merrell Dow's Seldane (terfenadine) and Janssen's Hismanal (astemizole) nonsedating antihistamines, Tracy emphasized that "we see no cardiotoxicity at all" with acrivastine. In July, FDA told MMD to provide a boxed warning on Seldane labeling to alert physicians to serious cardiovascular side effects that resulted from drug interactions and overdoses of Seldane ("The Pink Sheet" July 13, p. 9). Janssen agreed to add a boxed warning later that month ("The Pink Sheet" July 27, p. 3). Acrivastine has been approved as a single agent in the U.K. under the tradename Semprex and in "nine other countries" under the tradename Prolert, Tracy said. Under the Duact name, a combination acrivastine/pseudoephedrine product is available in France, Denmark and Finland. "We anticipate a favorable review" of acrivastine by FDA, he concluded. BW also has trademarked the combo under the Prolert-D name. Tracy also mentioned that Burroughs Wellcome is "very pleased with the progress that we are making on our clinical program" in the U.S. for Navelbine (vinorelbine), a semisynthetic vinca alkaloid used for treatment of breast and lung cancer. At a symposium on cancer chemotherapy convened by the MD Anderson Cancer Center in October, investigators of the drug said that Navelbine showed "considerable activity in patients with breast cancer and with non-small cell lung cancer who were known to be resistant to vinca alkaloids" ("The Pink Sheet" Oct. 19, p. 10). Navelbine is marketed in Italy, France and Argentina by the French firm Pierre Fabre Medicament. Burroughs Wellcome licensed North American marketing rights to Navelbine from Pierre Fabre ("The Pink Sheet" Jan. 8, 1990, In Brief). Apart from updating the conference on drugs in development, Tracy noted that Burroughs Wellcome augmented its marketing forces. He said that 100 reps were added to its U.S. sales staff "this past summer," bringing the firm's total sales staff to about 850. During the past year, Burroughs' worldwide sales force increased from 2,300 to 2,600, he added.