A new proton pump inhibitor, esomeprazole (Nexium), has been launched by Astra Zeneca. It is the first proton pump inhibitor to be licensed for "on demand" use.
Esomeprazole is licensed for a number of indications. For treatment of symptomatic gastro-oesophageal reflux disease (GORD) without oesophagitis, a dose of 20mg once daily is recommended. Once symptoms have been resolved, an "on demand" regimen of 20mg daily can be used for subsequent symptom control. The company told The Journal on September 12 that in two randomised six-month studies of "on demand" use, patients, on average, only needed to take one dose of esomeprazole on one third of the days to control their symptoms effectively. Most patients took the product for three or fewer consecutive days.
Esomeprazole is the first proton pump inhibitor to be developed as a single optical isomer. It is the S-isomer from the mixture of two optical isomers in omeprazole. Dr Andy Thillainayagam (consultant gastroenterologist, Hammersmith Hospital, London), speaking at the launch of esomeprazole on September 12, said that esomeprazole was metabolised at a much slower rate than the R-isomer in omeprazole. This meant that there was more drug in the blood stream for a longer time and more was delivered to proton pumps in the stomach. He said that compared with omeprazole, there was a "60 per cent extra blocking of proton pumps", resulting in more sustained acid control for a longer period of time. Dr Thillainayagam added that the side effect profile of esomeprazole was very similar to that of omeprazole.
Esomeprazole is also indicated for the treatment of erosive reflux oesophagitis and long-term management of patients with healed oesophagitis to prevent relapse. It is further licensed for triple therapy, at a dose of 20mg in combination with clarithramycin 500mg and amoxycillin 1g (all twice daily for seven days), for the eradication of Helicobacter pylori and healing of H pylori associated duodenal ulcers and prevention of relapse of peptic ulcers in patients with H pylori associated ulcer disease (see PJ, September 9, p378).
Commenting on the doses of esomeprazole, Astra Zeneca said that, milligram for milligram, esomeprazole provided greater acid secretion compared with omeprazole. When omeprazole was launched there were concerns about over suppression of acid but studies have shown that increased suppression improves clinical results, the company said. In acid suppression studies, esomeprazole 40mg was shown to provide better levels of acid suppression than both esomeprazole 20mg and omeprazole 20mg and was therefore the dose chosen.
On a cost comparison basis for a one month course, esomeprazole 40mg cost the same as omeprazole 20mg for treating reflux oesophagitis. Esomeprazole 20mg cost £18.50 for 28 tablets compared with £28.56 for 28 omeprazole 20mg. If used as "on demand" therapy for these patients the cost of esomeprazole 20mg, based on study data, would be reduced by one third, said Astra Zeneca.
| Correction The penultimate paragraph incorrectly says that esomeprazole "provided greater acid secretion". It should say "provided greater acid supression". |