BURROUGHS WELLCOME’s MEPRON WILL BE AVAILABLE IN MID-DECEMBER

BURROUGHS WELLCOME's MEPRON WILL BE AVAILABLE IN MID-DECEMBER to treat mild-to-moderate Pneumocystis carinii pneumonia in patients intolerant to trimethoprim/sulfamethoxazole (TMP/SMX). The drug was approved Nov. 25 as an "acute oral" second-line treatment for PCP after a seven-month review by FDA. Mepron received a Notice of Compliance from Canada's Health Protection Branch simultaneous with its FDA approval. The drug underwent a joint, integrated review by the two government regulatory authorities. Burroughs Wellcome is pricing a three-week course of Mepron (atovaquone) therapy to wholesalers at $402. By comparison, TMP/SMX is priced at $40-$115 and I.V. pentamidine at $1,700 for a course of therapy. B-W will place a spending cap on the annual cost of Mepron to patients who require multiple courses of therapy. Patients who take more than 411 g of Mepron a year and do not have third-party coverage will receive medication for the rest of the year at no cost, up to an additional 684 g. Mepron is taken as three 250 mg tablets t.i.d. for three weeks. Mepron's approval was based on two studies submitted by Burroughs Wellcome comparing atovaquone with the two other drugs approved for treating PCP, TMP/SMX and pentamidine. On Sept. 23, after reviewing these comparative studies, FDA's Antiviral Drug Products Advisory Committee recommended that Mepron be approved as a second-line therapy ("The Pink Sheet" Sept. 28, p. 5). The double-blind, randomized comparative trial with TMP/SMX was initiated in 1990 and enrolled 408 patients at 37 study centers. Mepron was found to be less effective but also less toxic than TMP/SMX: 62% of Mepron patients were defined as having a therapy success compared to 64% of patients on TMP/SMX, approved labeling reports. Atovaquone's lack of response as a reason for therapy failure was 17% compared to 6% for TMP/SMX, while therapy failure rates due to adverse experiences were 7% and 20%, respectively. The drug was associated with a statistically significant higher mortality rate. Eight percent of the 160 patients receiving Mepron and 2.5% of the 162 patients receiving TMP/SMX in the same trial died during the 21-day treatment course or during the eight- week follow-up period, labeling states. There was no difference in mortality rates in the pentamidine comparison trial, an unblinded randomized trial initiated in 1991. The trial enrolled a total of 174 patients at 22 study centers. Approximately 80% of the trial participants had a history of intolerance to trimethoprim or sulfa-antimicrobials or were demonstrating intolerance to TMP/SMX during a bout of PCP. Patients receiving Mepron and intravenous pentamidine both had a mortality rate of 14% through the eight-week follow-up period. As in the comparison trial to TMP/SMX, Mepron was found to have a higher rate of therapy failure than I.V. pentamidine due to lack of response (29% compared to 17%) but a significantly lower rate of failure due to adverse experience (3.6% compared to 36%), giving comparable therapeutic efficacy overall. Approximately 80% of people with AIDS get PCP during the course of the disease. Burroughs Wellcome estimates that as many as 50%-80% may experience significant side effects from TMP/SMX. In the company's comparison study of TMP/SMX and Mepron, 20% of the people with AIDS taking TMP/SMX were forced to discontinue treatment because of adverse reactions to the drug. The two studies Burroughs Wellcome conducted involved over 450 people with AIDS who had mild-to-moderate PCP. More than 900 people with PCP have received the drug free of charge through a Treatment IND, which FDA granted the firm on Nov. 8, 1991. Burroughs Wellcome plans to make Mepron available at no cost to financially-disadvantaged individuals not covered under state or federal assistance programs. Promotional plans for Mepron include journal advertisements, direct mail and patient information booklets. The drug will be detailed by 800 B-W sales reps who will target physicians who treat HIV patients, infectious disease specialists and pharmacists.