Data presented this week at the Digestive Disease Week conference in San Diego, US, suggest that esomeprazole may be clinically superior to omeprazole. Esomeprazole (Nexium), Astra Zeneca's new proton pump inhibitor (PPI), is not currently available in the UK.
One study found that esomeprazole was superior to omeprazole for healing erosive oesophagitis. Dr Joel Richter (Cleveland clinic, Ohio, US) and colleagues found that esomeprazole had a similar healing rate at four weeks as omeprazole had at eight weeks. The study compared 1,216 patients taking esomeprazole and 1,209 patients taking omeprazole. The recommended daily doses of each drug were used - 20mg omeprazole and 40mg esomeprazole. After four weeks, 82 per cent of the esomeprazole group were healed and, after eight weeks, 94 per cent, compared with 69 and 84 per cent for omeprazole. Dr Richter commented: "Esomeprazole is the first drug with the potential to offer significant clinical advantages over omeprazole in symptom resolution and healing in patients with all grades of erosive oesophagitis."
In a similar trial of 1,960 patients, Dr Peter Kahrilas (Northwestern university medical school, Chicago, US) and colleagues concluded that esomeprazole was superior to omeprazole for healing of erosive oesophagitis and also provided greater heartburn resolution. Both trials found that the safety profile for the two drugs was similar.
In a pharmacokinetic study of 38 patients which measured intragastric pH, Dr T. Lind (Karnsjukhuset, Skovde, Sweden) and colleagues found that esomeprazole provided more effective acid control than omeprazole with less interpatient variability.
Astra Zeneca commented that these and other studies presented at the meeting indicate that acid control is more predictable with esomeprazole than with other PPIs. Esomeprazole is one of the two optical isomers of omeprazole. The company claims that, as a result, esomeprazole has greater predictability of response, enhanced speed and duration of effect and "advantageous metabolism".