VICKS VAPORUB CREAM CLINICAL TRIAL HAS "GOOD DESIGN"

VICKS VAPORUB CREAM CLINICAL TRIAL HAS "GOOD DESIGN," FDA Office of OTC Drug Evaluation consultant Michael Weintraub, MD, told Procter & Gamble representatives at an Oct. 27 OTC "feedback" meeting. "It is a good design and the results are quite clear," Weintraub said. However, he added that FDA cannot "really make a final comment until" the study and its results are submitted to the agency for review. At the meeting, Rich-Vicks' parent Procter & Gamble presented FDAers with results from a clinical trial that compared the efficacy of its new cream formulation of VapoRub with the efficacy of its marketed VapoRub ointment. The OTC office informed P&G in an Aug. 7 letter that although FDA had considered the company's proposed protocol for in vitro studies of the cream formulation, clinical trials were necessary to determine the safety and effectiveness of the new VapoRub cream product ("The Pink Sheet" Aug. 24, T&G-12). P&G submitted the in vitro protocol in 1989. P&G Toxicology Group Leader Robert Bookstaff, PhD, told the OTC office staff that the company will submit its report on the clinical trial to FDA in three months since some human and animal safety studies are still ongoing. P&G Regulatory Affairs Section Head William Kozarek, PhD, said the objective of the trial was to "demonstrate clinical equivalence by comparison of VapoRub [ointment] to the VapoRub cream in a citric acid aerosol-induced cough trial." The trial was a single-blind (technician-blind), randomized, four-way crossover study, P&G Respiratory Clinical Development Associate Director Donald Riker, PhD, said. Each study subject received each of the four treatments: the cream product, the ointment, the matched control to the cream and the matched control to the ointment. Forty-four subjects applied 7.5 grams of material to the upper chest and neck. To qualify for the study,subjects had to have 10 or more coughs during baseline challenge, Riker noted. Subjects were rechallenged at different time intervals up to three hours. The primary outcome variables were the "measure of total relief defined as area under the response curve from 0 to 180 minutes" and "the measure of peak relief, which occurs within the first hour and a half," Riker said. Summarizing the study results, Riker said that for the primary variable outcomes "both products produced significantly greater overall cough reduction defined by AUC and peak decreases in cough compared to their respective vehicle controls." He added that "the active treatments were not significantly different from one another for either primary variable." Riker stated that "these results indicate that the efficacy of the VapoRub cream formula is equivalent to that of the current commercial product and that these data support the functional equivalency of these two products." P&G hopes that the study data will support Category I (safe and effective) classification for the cream formulation in the final monograph for OTC cough/cold combination drug products. VapoRub ointment was proposed as Category I as an antitussive and Category III as a decongestant in the OTC cough/cold combo tentative final monograph published in August 1988. FDA is reviewing data from a clinical trial that the company submitted to get Category I status for VapoRub ointment as a nasal decongestant.