ROCHE's FLUMADINE (RIMANTADINE) IS SAFE AND EFFECTIVE FOR INFLUENZA A TREATMENT AND PROPHYLAXIS, FDA COMMITTEE SAYS; ANTIVIRAL SAFETY PROFILE HIGHLIGHTED

Roche's Flumadine (rimantadine) is safe and effective for treatment and prophylaxis of influenza A, FDA's Anti-Infective Drugs Advisory Committee concluded at its Oct. 27 meeting. After a brief discussion, the committee agreed that the 13 controlled studies submitted in support of the prophylaxis and treatment indications established safety and modest efficacy. "The data have been accumulated over many, many years, [and] they've shown a modest clinical improvement, which in individual cases or for epidemiologic purposes may have some value," committee member Calvin Kunin, MD, Ohio State University Department of Medicine commented. "This is not an extraordinary wonder drug, but I believe they've made their case in relationship to the claim -- for minor relief of symptoms of influenza . . . or for prophylaxis," Kunin added. Several questions were raised about the clinical significance of the efficacy results. However, the review was apparently timed to precede the upcoming flu season. FDA Anti-Infective Drug Products Division Director Edward Tabor, MD, noted at the beginning of the meeting that the division feels "a responsibility to at least act on this NDA before the flu season gets well underway." In the first five minutes of the meeting, two committee members also suggested expediting a vote. The rimantadine NDA, submitted in November 1986, includes six double-blind controlled studies for prophylaxis of influenza A, seven double-blind controlled studies for treatment of influenza A, and several studies without controls. In total, the firm's data base includes information on approximately 2,000 patients who have received rimantadine. The studies were primarily conducted by DuPont before Roche licensed the antiviral in 1986. They cover pediatric, healthy adult, and geriatric populations. The studies evaluated doses from 200-400 mg/day for adults and 5-7 mg/kg/day for children. Roche noted that two studies comparing rimantadine to amantadine (DuPont's Symmetrel) show that the two agents have almost identical efficacy but that rimantadine has a lower side effect profile. The firm reported that in a prophylaxis study in which 145 patients received rimantadine, 143 received amantadine, and 148 received placebo, the adverse drug reaction rate was 6.9% in the rimantadine group compared to 14.7% in the amantadine group and 4.1% in the placebo group. A study on the treatment of influenza with approximately 20 patients in each arm found that 25% of the rimantadine and placebo patients had adverse reactions, while 44% of the amantadine group had adverse reactions. Roche suggested that the antiviral be labeled for 200 mg b.i.d. dosing for adults and 5-7 mg/kg/day dosing for children. Treatment length, Roche said, should be up to six weeks for prophylaxis and 5 days for treatment. The company currently is conducting a trial in geriatric patients that is evaluating the antiviral's affect on flu complications and ability to resume activity. Roche is also conducting studies that are evaluating whether or not treated flu patients have reduced potential for transmitting influenza to untreated subjects.