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| |  ACG: Caution Needed In Translating Clinical Trial Results To The Clinical Setting By Cameron Johnston Special to DG News LAS VEGAS, NV -- October 24, 2001 -- Clinical trial results that might look good at first glance often don't translate into changes in prescribing habits on the parts of doctors who the trial results are aimed at. The data, which might show statistical significance on paper, might not have any clinical significance, and as a result, doctors might not act on the latest data, even if it is favorable. A case in point is a poster presented at this year's annual meeting of the American College of Gastroenterology, by Dr. Alan Thomson, a rheumatologist at the University of Alberta Hospital, in Edmonton, Canada. Dr. Thomson evaluated the effectiveness of esomeprazole 40 mg against lansoprazole 30 mg in a single dose study to determine whether one was superior to the other for control of gastric acid. The study results showed that esomeprazole was superior, maintaining gastric pH >4 for 57.2 percent of the time as compared with lansoprazole which maintained gastric pH at >4 or 51.8 percent of the time over a 24-hour period (p=0.005). The study was conducted among 28 helicobacter pylori negative subjects, mean age 25, who were tested with each of the study drugs at least 10 days apart. Does this translate into a clinical difference though? Dr. Thomson, who was principal investigator on the study, said it's impossible to say. A snapshot study such as this can't show that patients were any better off just because their gastric acid is maintained at >4 for a slightly greater percentage of a 24-hour period. Similarly, he said, another study comparing the two drugs showed that esomeprazole offered better healing of erosive esophagitis than lansoprazole. But out of the 5241 adults with endoscopically confirmed erosive esophagitis in this study, the real difference in healing rates were less than five percent at both week four and week eight. These numbers are big enough to show statistical significance, but the difference between the two was "small… very small," he said. "Are family doctors who prescribe these drugs going to tell the patient that they'll have a five percent chance of doing better if they switch to another drug? I don't think so," he said. The crux of the issue is that the makers of all of the proton pump inhibitors, at this time, lansoprazole, omeprazole, esomeprazole, pantoprazole and rabeprazole are all trying to claim that in one way or another, their drugs are superior, whereas there are relatively few clinical differences between them, Dr. Thomson said. Indeed, at the ACG meeting there were no fewer than 54 separate presentations dealing with the five proton pump inhibitors. According to Dr. Philip Miner, who spoke in a separate presentation, said all of the currently available PPIs claim eight-week healing rates of 90-92 percent with no statistically significant difference in these findings. Some PPIs such as lansoprazole and rabeprazole, however seem to be associated with faster onset of action, and more rapid relief within the first two or three days of treatment. As well, Dr. Donald Castell, director of esophageal disorders at the Medical University of North Carolina, pointed out that pantoprazole and rabeprazole have been found in clinical trials to have better action against nocturnal acid breakthrough. Ultimately, for family doctors who prescribe most PPIs, this is not a "one size fits all" situation, and it cannot be said that one PPI is superior in all cases, and that careful consideration will have to be given to the patient's individual symptoms.
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