REID-ROWELL's ROWASA RECTAL SUSPENSION SHOULD BE APPROVED
REID-ROWELL's ROWASA RECTAL SUSPENSION SHOULD BE APPROVED for the treatment of ulcerative colitis, FDA's Gastro-Intestinal Drugs Advisory Committee agreed at a Dec. 9 meeting. Explaining an approval recommendation, committee reviewer Bertram Fleshler, MD, Cleveland Clinic Foundation, said: "There seems to be little doubt as to the efficacy of the preparation." Reid-Rowell already markets a hydrocortisone retension enema (Cortenema) as adjunctive treatment for ulcerative colitis. Fleshler noted that the "four gram dose of the formulation given [in the study] . . . clearly seems to be better than placebo at both three weeks and six weeks. And, therefore, my own opinion would be that this would be an approvable preparation." The committee's discussion centered on whether Rowasa (5-amino-salicylic acid, or 5-ASA) rectal suspension had been proven safe and efficacious given a lack of data supporting 4 grams as the optimal dose. FDA also considered the sponsor's NDA to contain only one clinical trial. The committee also examined whether 5-ASA, a component of the approved drug sulfasalazine, could be considered an "old drug product" based on its similarity to sulfasalazine (Azulfidine). Commenting on the dose, Fleshler noted "that we don't really know the proper dose to give." The 4 mg "dose may be too much or maybe it's too little," Fleshler said. However, he pointed out, the 4 mg dose is efficacious. FDA noted in a handout to the committee that "the multicenter clinical trial performed by the sponsor was originally . . . proposed as one multicenter trial, but because it was conducted with some centers in the U.S. and other centers in Canada, it has been considered two independent trials by the sponsor." FDA Cardio-Renal Drugs Division Director Raymond Lipicky, MD, told the committee that "the distinction between one and two studies here is a relatively critical one . . . because the agency desires to see replication [i.e., at least two well-controlled trials]." Alternatively, Lipicky said, "one could argue . . . that 5-ASA is not a new drug." He explained that "in those situations . . . the agency usually says that one trial is enough." The committee was split as to whether 5-ASA should be considered a new drug or an old drug, and whether the NDA contained one trial or two. Noting the disagreement on the panel, committee Chairman Donald Wilson, MD, State University of New York-Downstate Medical Center, summarized: "While it may be felt to be one trial [by some committee members] . . . I suspect that what's going on is that . . . it is felt to be one very good trial." Several committee members who felt the NDA consisted of one trial commented that the current data was sufficient for approval, either because the drug could be considered an "old drug" or because the eight-center, 150-subject study had similar results in all centers and thus could be considered, from a scientific point of view, to have replication. Rowasa was recently approved for use in Canada based on Reid-Rowell's Canadian/U.S. trial. The rectal suspension formulation is not currently marketed in Europe; however, Reid-Rowell's 5-ASA development partner, the West German firm Interfalk AG, markets 5-ASA in Europe in tablet and suppository form. Reid-Rowell submitted its Rowasa NDA in June 1986.
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