Inhibitors in haemophilia A: a perspective on clotting factor products as a potential contributing factor.

INTRODUCTION: The occurrence of a neutralizing antibody in previously untreated patients (PUPs) with haemophilia A appears to be the result of an intricate interplay of both genetic and environmental factors. Recently, the type of factor VIII (FVIII) product used in the PUPs population has been implicated as a risk factor for inhibitor development. AIM: The aim of this review was to explore in a systematic manner potential hypotheses for the product-related findings in these studies (i.e. differences in the expression system of the cell lines used to produce recombinant FVIII [rFVIII], differences in the administered antigen load or changes in clinical practice over time). RESULTS: Review of the available clinical studies illustrates the high degree of variability for the risk of inhibitor development for the same products across different studies. Differences in cell lines or antigen load were not found to provide a reasonable explanation. CONCLUSION: The possibility of changes in clinical practice over time and patient selection bias (i.e. the preferential use of one product over another in patients at higher risk for inhibitors) offers a potential explanation and should be carefully considered when evaluating the studies.

Managing chronic pain in adults with haemophilia: current status and call to action.

Haemophilic arthroses are associated with acute pain during bleeding episodes and with chronic pain caused by arthritic complications of repeated bleeding into joints. Unlike other conditions (e.g. osteoarthritis, rheumatoid arthritis, sickle cell disease), there are limited data on pain management in haemophilia. Management of arthritic individuals and those with sickle cell disease relies heavily on administration of acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs) and opioid analgesics. In haemophilia, acetaminophen often has limited efficacy at therapeutic doses, offering a narrow dosing range in those with liver disease due to chronic hepatitis C. NSAIDs can effectively manage pain in patients with haemophilia, but these agents are potentially associated with a significant risk of precipitating or exacerbating bleeding complications in an already coagulopathic population. Opioids have proven effective in osteoarthritis and sickle cell disease, but outcomes data in those with haemophilia are virtually non-existent. Patients with haemophilia are at least as vulnerable as other chronic pain populations to opioid-related adverse events and to developing abusive behaviours and addiction. Despite pain management strategies for patients with haemophilia being far from optimal, the predominant precept of haemophilia management still applies. As such, it is critically important to aggressively reverse or prevent acute symptomatic bleeding in a timely and effective manner to at least minimize pain and progressive joint damage. This review should serve as a call to action to prioritize pain management in haemophilia care and spur interest in the development, improvement and standardization of tools to assess and manage acute and chronic pain in haemophilia.

Cardiovascular comorbidities are increased in U.S. patients with haemophilia A: a retrospective database analysis.

There is conflicting evidence in the literature on whether individuals with haemophilia in the USA have greater, reduced, or similar risks for cardiovascular disease as the general population. This study evaluated the prevalence of cardiovascular comorbidities among USA males with haemophilia A, relative to an unaffected general male population with similar characteristics. Males with haemophilia A and continuous insurance coverage were identified by ICD-9-CM code 286.0 (1 January 2007-31 December 2009) using the MarketScan Commercial and Medicare Research Databases. Individuals with haemophilia A were exact matched 1:3 with males without a diagnosis of haemophilia A. The prevalence of cardiovascular comorbidities identified by ICD-9-CM code was determined for matched cohorts. Of the study population, 2506 were grouped in the haemophilia A cohort and 7518 in the general cohort. Proportions of individuals with haemorrhagic stroke (2.0% vs. 0.5%, P < 0.001), ischemic stroke (4.7% vs. 2.7%, P < 0.001), coronary artery disease (10.7% vs. 5.8%, P < 0.001), myocardial infarction (0.8% vs. 0.3%, P = 0.003), hypertension (22.6% vs. 15.5%, P < 0.001), hyperlipidaemia (15.9% vs. 11.9%, P < 0.001), arterial thrombosis (12.1% vs. 5.9%, P < 0.001), and venous thrombosis (4.4% vs. 1.1%, P < 0.001) were significantly greater for the haemophilia A cohort. Results were consistent across most age groups, and comorbidities appeared at an earlier age in those with haemophilia A than in the general population. Among the USA haemophilia A population cardiovascular comorbidities are more prevalent and they appear earlier in life in comparison to the general male population, suggesting the need for earlier, enhanced screening for age-related comorbidities in the haemophilia community.

The challenge of pain evaluation in haemophilia: can pain evaluation and quantification be improved by using pain instruments from other clinical situations?

Pain is a critical aspect in the lives of individuals with congenital haemophilia A or B. Initially, pain serves as a warning sign for an active bleeding event; however, after multiple bleeding episodes, pain may become chronic, debilitating, and distracting. It is essential that pain instruments be developed and validated for use in persons with haemophilia, especially in paediatric cohorts, so that new therapies to treat acute bleeds can be assessed in a standardized manner. This review evaluates the existing pain instruments utilized in the English language haemophilia literature and compares their features and practicality with instruments published for other clinical pain scenarios associated with non-coagulopathic disease states, such as cancer and surgical convalescence, in paediatric, adolescent, and adult populations. In clinical trials involving haemophilia cohorts, few pain instruments have been validated. Only one instrument has addressed pain specifically in individuals less than 16 years of age. In contrast, multiple instruments have been applied extensively to other pain situations, especially in the paediatric oncology area, where the age range extends to less than 3 years. We conclude that trials quantifying pain in haemophilia would benefit from the addition and validation of instruments in use in other pain situations. Suggestions for modifying the pain instruments currently used in haemophilia are presented, specifically to address paediatric haemophilia cohorts.

PEGylated therapeutic proteins for haemophilia treatment: a review for haemophilia caregivers.

PEGylation is the technology involving the covalent attachment of polyethylene glycol (PEG) to a protein-, peptide- or small-molecule drug to improve their pharmacokinetic, pharmacodynamic and immunological profiles, and thus, enhance the therapeutic effect. Today, PEGylation of proteins is a well-established technology and is being used in the treatment of a variety of clinical disorders. Several PEGylated coagulation proteins for haemophilia A and B are under development with the goal of prolonging the circulation half-life of factor VIII (FVIII) or factor IX. The prolongation of half-life, resulting in less frequent injections can provide significant benefits in improving the quality of life of subjects with haemophilia and improvement in adherence to treatment. A review of published literature on PEGylated therapeutic products currently approved for human use and a discussion of a PEGylated recombinant FVIII molecule (BAY 94-9027, Bayer HealthCare, Berkeley, CA, USA) currently being investigated in the pivotal clinical trial prior to registration is provided. Available safety information of PEGylated proteins containing high molecular weight PEG does not indicate any safety concerns to date, following long-term (chronic) use in animal models or patients. Chronic use of currently available PEGylated products has been shown to be safe, paving the way for chronic use of PEGylated coagulation products in persons with haemophilia.

Steroid-sparing properties of sargramostim in patients with corticosteroid-dependent Crohn's disease: a randomised, double-blind, placebo-controlled, phase 2 study.

OBJECTIVE: Although treatment with corticosteroids induces remission in Crohn's disease, prolonged exposure to corticosteroids is undesirable. This randomised clinical trial evaluated the efficacy of recombinant human granulocyte-macrophage colony-stimulating factor (sargramostim), an activator of innate immunity, in corticosteroid-dependent patients with Crohn's disease. DESIGN: Patients were randomised in a 2:1 ratio, to sargramostim 6 microg/kg subcutaneously once daily or placebo for up to 22 weeks. The study consisted of (1) an adjunctive phase (weeks 1-4) in which patients received study drug plus corticosteroid therapy; (2) a forced corticosteroid tapering phase (weeks 4-14); and (3) an observation phase (4 weeks) in which patients received study drug plus prednisone < or =7.5 mg. The primary endpoint was corticosteroid-free remission (Crohn's Disease Activity Index (CDAI) < or =150) 4 weeks after corticosteroid elimination. Secondary endpoints were corticosteroid-free response (CDAI decreased by > or =100) and induction of remission in patients who reduced the dose of corticosteroid to 2.5-7.5 mg. RESULTS: Eighty-seven patients were randomised to sargramostim and 42 to placebo. Significantly more sargramostim-treated patients than placebo patients achieved corticosteroid-free remission (18.6% vs 4.9%; p = 0.03). Similar differences were seen for corticosteroid-free response and in patients who tapered corticosteroids to 2.5-7.5 mg/day. Sargramostim treatment was also associated with significant improvements in health-related quality of life. Patients who received sargramostim were more likely to experience musculoskeletal pain, injection site reactions and dyspnoea. CONCLUSIONS: Sargramostim was more effective than placebo for inducing corticosteroid-free remission in patients with Crohn's disease with corticosteroid dependence. Sargramostim may provide significant benefit in this population if these findings are confirmed.

Mass balance study of [14C] rabeprazole following oral administration in healthy subjects.

The study was designed to determine the excretion balance of radiolabeled rabeprazole in urine and feces and to examine the metabolite profile in plasma, urine and feces after a single oral dose of [14C] rabeprazole, preceded by once daily dose of rabeprazole for 7 days. Six healthy subjects were enrolled in this study. The study was a single-center, open-label, multiple-dose, mass-balance study. Each subject received a single 20 mg dose of rabeprazole tablet for 7 days followed by the administration of 20 mg of [14C] rabeprazole as an oral solution after an overnight fast on Day 8. After oral dosing of [14C] rabeprazole, the mean Cmax of total radioactivity was 1,080 +/- 215 ng equivalent/ml with 0.33 +/- 0.13 hours of the mean tmax. The apparent elimination half-life of total [14C] radioactivity was 12.6 +/- 3.4 hours. The total [14C] recovery in urine and feces was 99.8 +/-0.7% by 168 hours after oral administration of [14C] rabeprazole, and mean cumulative [14C] radioactivity excreted in urine was 90.0 +/- 1.7% by 168 hours and 79.8 +/- 2.5% of the radioactivity was excreted in urine within 24 hours. Excretion via feces added to the total by 9.8%. The major radioactive component in the early plasma samples was rabeprazole, however the thioether and thioether carboxylic acid metabolites were the main radioactive components in the later plasma sample. These results support the previous finding that the substantial contribution of the non-enzymatic thioether pathway minimizes the effect of CYP2C19 polymorphism on the inter-individual variation ofplasma clearance of rabeprazole compared with other PPIs. Low levels of the sulfone metabolite were detected only in early plasma samples. No rabeprazole was detected in any urine and feces samples. The main radioactive components in urine were thioether carboxylic acid and mercapturic acid conjugate metabolites, and in the feces, the thioether carboxylic acid metabolite. The administration of [14C] rabeprazole was safe as evidenced by the lack of serious adverse events and the fact that all observed events were mild in intensity. [14C] rabeprazole was rapidly absorbed after oral administration and mostly excreted in urine.

Famotidine relieves symptoms of gastroesophageal reflux disease and heals erosions and ulcerations. Results of a multicenter, placebo-controlled, dose-ranging study. USA Merck Gastroesophageal Reflux Disease Study Group.

We conducted a double-blind, placebo-controlled, multicenter trial comparing the efficacy of famotidine 40 mg administered at bedtime (HS), 20 mg given twice daily (BID), and placebo to relieve heartburn and to heal endoscopically documented esophageal erosions or ulcerations. A total of 338 patients were randomized: 135 to receive famotidine 40 mg HS, 137 to receive famotidine 20 mg BID, and 66 to receive placebo. In the group given famotidine 20 mg BID, there was a significantly greater proportion of patients with complete relief of daytime heartburn, and both famotidine groups demonstrated statistically significant advantages over placebo in global scores or by successful outcome. Antacid consumption was significantly reduced in the group given famotidine 20 mg BID as compared with placebo. Both famotidine regimens resulted in a significantly greater proportion of patients with complete endoscopic healing than placebo, with the BID dosing being numerically superior to the 40-mg HS dose.

Review article: drug interactions with agents used to treat acid-related diseases.

Patients with acid-related diseases often need to take multiple medications. Treatment of Helicobacter pylori infection often includes either a histamine type 2 (H2)-receptor antagonist or a proton pump (H+,K(+)-ATPase) inhibitor (proton pump inhibitor), administered in conjunction with one or more antimicrobials. Also, treatment for acid-related diseases often requires extended therapy during which many concomitant medications may be administered for concurrent disease states. Polypharmacy may be the result, particularly in elderly patients, who are at increased risk for both acid-related and many other diseases. Thus, it is important to understand the potential for clinically significant drug-drug interactions in this setting. H2-receptor antagonists and proton pump inhibitors can influence the pharmacokinetic profiles of other commonly administered medications by elevating intragastric pH, which can alter drug absorption, and by interacting with the cytochrome P (CYP) 450 enzyme system, which can affect drug metabolism and clearance. Such interactions are particularly important when they affect the pharmacokinetics of drugs with narrow therapeutic ranges (e.g. warfarin, digoxin). In these cases, drug-drug interactions can result in significant toxicity and even death. There are marked differences among H2-receptor antagonists and proton pump inhibitors in their potential for such interactions. The oldest drugs in each class, cimetidine and omeprazole, respectively, have the greatest potential to alter CYP activity and change the pharmacokinetics of other drugs. The most recently developed H2-receptor antagonist, famotidine, and the newer proton pump inhibitors, rabeprazole and pantoprazole, are much less likely to induce or inhibit CYP and thereby change the metabolism of other medications. These differences are important when choosing medications for the safe treatment of patients with acid-related diseases.

Review article: rabeprazole's profile in patients with gastrointestinal diseases.

The selection of agents to treat patients with acid-related gastrointestinal diseases requires knowledge of their efficacy, tolerability, and ease of dosing among individuals with differing disease severities and other baseline characteristics. The efficacy and favourable benefit-risk profile of rabeprazole, a new proton pump inhibitor, has been demonstrated in controlled clinical trials of patients with gastro-oesophageal reflux disease (GERD), duodenal ulcers, and gastric ulcers. In comparative trials, rabeprazole is at least as effective as omeprazole for the treatment of GERD, duodenal ulcers, and gastric ulcers, and it is superior to histamine2-receptor antagonists for the treatment of GERD and duodenal ulcers. Its once-daily dosing regimen and low potential for interaction with drugs metabolized by the cytochrome P450 system make it a particularly attractive option for the treatment of acid-related diseases among older individuals. Rabeprazole is likely to be a valuable new addition to its class in treating patients with acid-related gastrointestinal diseases given its efficacy in acid suppression, high healing rates, rapid symptom relief, and convenient dosing.

Dose--response effect of famotidine on patterns of gastro-oesophageal reflux.

The present study attempts to assess the alteration in patterns of gastro-oesophageal reflux as assessed by 24-h oesophageal pH monitoring by varying degrees of H2-receptor blockade with famotidine. Subjects were 12 patients with complaints of daily heartburn who demonstrated at least 6% of acid mucosal contact time by 24-h ambulatory oesophageal pH monitoring. All subjects had a positive Bernstein test, and nine of the 12 subjects had erosive oesophagitis. The study was conducted as a double-blind crossover design utilizing 40 mg nocte, 20 mg b.d., and 40 mg b.d. and placebo treatments. Results indicated that all treatments significantly reduced the 24-h percentage acid contact time (P less than 0.05) compared to placebo. The two b.d. treatment regimens also significantly (P less than 0.05) reduced the number of episodes lasting longer than 5 min. Only the b.d. regimens successfully lowered the percentage of upright acid exposure. All treatments significantly (P less than 0.01) reduced the percentage of supine acid contact time, as well as the number of episodes lasting more than 5 min. It is concluded that gastro-oesophageal reflux disease may well require a b.d. dosing regimen with famotidine in order to achieve optimal mucosal healing and day time symptom control.

Decreasing oesophageal acid exposure in patients with GERD: a comparison of rabeprazole and omeprazole.

BACKGROUND: Rabeprazole has been shown to be more potent and faster than other proton pump inhibitors in in vitro studies and highly effective in decreasing oesophageal acid exposure in patients with gastro-oesophageal reflux disease (GERD). AIM: This study was a multicentre, double-blind, placebo-controlled, randomized, parallel-group comparison of three active treatment regimens utilizing two different proton pump inhibitors, or placebo, administered over 7 days in patients with GERD. METHODS: Eighty-two patients with symptomatic GERD were given placebo, rabeprazole 10 mg b.d., rabeprazole 20 mg o.m., or omeprazole 20 mg o.m. for 7 days. Twenty-four hour oesophageal pH monitoring was performed at baseline and repeated at the conclusion of the treatment period. RESULTS: At the end of study, the percentage time (mean +/- s.d.) with pH < 4 over a 24-h period was significantly decreased by the three active regimens but without significant difference between them (9.27 +/- 4.77; 2.53 +/- 4.27; 2.02 +/- 1.71 and 2.91 +/- 4.06 for placebo, rabeprazole 10 mg b.d., rabeprazole 20 mg o.m. and omeprazole 20 mg o.m., respectively). Acid exposure was normalized in 90% of patients treated with rabeprazole 10 mg b.d., 95% treated with rabeprazole 20 mg o.m., 78% treated with omeprazole 20 mg o.m., and only 9.5% of patients treated with placebo. Both rabeprazole and omeprazole were well-tolerated. CONCLUSIONS: Although rabeprazole 20 mg o.m. showed greater activity numerically, this study demonstrates that rabeprazole 10 mg b.d. and 20 mg o.m. are equivalent to omeprazole 20 mg o.m. in decreasing oesophageal acid exposure.

A randomized, double-blind trial of the efficacy and safety of 10 or 20 mg rabeprazole compared with 20 mg omeprazole in the maintenance of gastro-oesophageal reflux disease over 5 years.

BACKGROUND: Gastro-oesophageal reflux disease has a chronic course, and often requires long-term treatment. Proton pump inhibitors are the treatment of choice for both acute and maintenance treatment, but little is known from randomized controlled trials of their effects beyond 1 year. AIM: To compare the efficacy and safety of two doses of rabeprazole with 20 mg omeprazole in the maintenance treatment of erosive gastro-oesophageal reflux disease over 5 years. METHODS: Two hundred and forty-three patients who had previously responded to acute treatment for erosive gastro-oesophageal reflux disease were prospectively randomized to receive 5 years of treatment with rabeprazole (10 or 20 mg daily) or omeprazole (20 mg daily). The primary outcome measure was endoscopically confirmed relapse of erosive gastro-oesophageal reflux disease. RESULTS: One hundred and twenty-three patients (51%) completed all 5 years of the study, with similar completion rates in the three groups. Relapses occurred in nine of 78 (11.5%), eight of 82 (9.8%) and 11 of 83 (13.3%) patients in the rabeprazole 20 mg, rabeprazole 10 mg and omeprazole 20 mg groups, respectively. Gastric biopsy showed no evidence of any harmful effects. All treatments were well tolerated. CONCLUSIONS: Rabeprazole 10 mg, rabeprazole 20 mg and omeprazole 20 mg all had similar efficacy in the maintenance treatment of gastro-oesophageal reflux disease. All three were safe and well tolerated during 5 years of treatment.

Comparison of rabeprazole 20 mg vs. omeprazole 20 mg in the treatment of active gastric ulcer--a European multicentre study. The European Rabeprazole Study Group.

BACKGROUND: Rabeprazole sodium is the newest member of a class of substituted benzimidazole molecules known as proton pump inhibitors. Other proton pump inhibitors have been shown to be effective in healing active, benign gastric ulcers. METHODS: In this randomized, double-blind, multicentre study, conducted at 25 European sites, rabeprazole and omeprazole were compared in patients with active gastric ulcers. Two hundred and twenty-seven patients with active benign gastric ulcer were randomized to receive either rabeprazole 20 mg (n = 113) or omeprazole 20 mg (n = 114) once daily for 3 or 6 weeks, with healing monitored by endoscopy. RESULTS: After 3 weeks, complete healing (ITT analysis) was documented in 58% of patients given rabeprazole and 61% in patients given omeprazole (N.S.). After 6 weeks the healing rates were identical in both groups at 91%. Rabeprazole-treated patients had numerically greater symptom relief at all 12 points of comparison. The differences significantly favoured rabeprazole at week 3 for daytime pain improvement (P = 0.023) and at week 6 for pain frequency (P = 0.006) and complete resolution of night pain (P = 0.022). Both drugs were well-tolerated over the 6-week treatment course. Mean changes from baseline to end-point in fasting serum gastrin were comparable. No significant differences in laboratory parameters were seen. CONCLUSION: In this study, rabeprazole produced healing rates comparable to omeprazole at weeks 3 and 6, but provided more consistent and occasionally significantly superior symptom improvement. Both treatments were well-tolerated.

Effects of oral rabeprazole on oesophageal and gastric pH in patients with gastro-oesophageal reflux disease.

BACKGROUND: This study examined the dose-response effects of the new proton-pump inhibitor rabeprazole on oesophageal and gastric pH in patients with gastro-oesophageal reflux disease. METHODS: This study had a single-centre, double-blind, randomized, two-way crossover design. Twenty patients were treated for two 7-day periods separated by a 7-10-day washout period. Patients were randomly assigned to receive either 20 mg of rabeprazole once daily during the first treatment period and 40 mg once daily during the second treatment period, or 40 mg during the first treatment period and 20 mg during the second treatment period. The primary efficacy variable was oesophageal acid exposure determined by 24-hour ambulatory pH monitoring. Acid-reflux time was defined as the percentage of time over 24 h that oesophageal pH was < 4. A dosage was considered effective if reflux time was reduced to < 6%, a number which has been our internal laboratory reference. RESULTS: Both rabeprazole 20 mg and 40 mg, given once daily, normalized reflux time, with decreases of 79% and 92% in acid exposure by day 7. Both dosages also decreased the mean total number of reflux episodes and the number of episodes lasting > 5 min, with no significant differences between dosages for any reflux parameter. Mean gastric pH increased with 20 mg from 1.86 at baseline to 3.71 on day 1 and 4.17 on day 7. Rabeprazole 40 mg once daily increased gastric pH from 2.01 to 4.37 on day 1, and to 4.65 on day 7. Safety analyses revealed no significant acute side-effects for either dosage. CONCLUSIONS: Pathological oesophageal acid exposure was normalized with both 20 mg and 40 mg dosages of rabeprazole, and the effects of these two doses did not differ. Rabeprazole was well-tolerated in this short-term study.

Double-blind comparison [correction of Double-blind, placebo-controlled comparison] of rabeprazole 20 mg vs. omeprazole 20 mg in the treatment of erosive or ulcerative gastro-oesophageal reflux disease. The European Rabeprazole Study Group.

BACKGROUND: Rabeprazole sodium is the most recent member of a class of substituted benzimidazole molecules known as proton pump inhibitors. Other proton pump inhibitors have been shown to be effective in healing oesophagitis. METHODS: In this randomised, double-blind, multicentre study, conducted at 27 European sites, the efficacy and safety of rabeprazole and omeprazole were compared in patients with erosive or ulcerative gastro-oesophageal reflux disease (GERD).100 patients received rabeprazole 20 mg, and 102 patients omeprazole 20 mg once daily for 4 or 8 weeks, with healing monitored by endoscopy. RESULTS: Overall GERD healing rates observed and evaluated at weeks 4 and 8 were equivalent. Four-week healing rates for rabeprazole and omeprazole were 81%-81% and 92%-94% for 8-week healing. Rabeprazole-treated patients had similar relief of the frequency and intensity of heartburn to those treated with omeprazole. Both drugs were well tolerated over the 8-week treatment period. Mean changes in fasting serum gastrin were comparable. No significant differences in laboratory parameters were seen. Biopsies for argyrophil ECL cell histology at the end-point revealed a similar distributions of hyperplasia grades to those at baseline in both groups. Biopsies of body and antral mucosa for other parameters were similar between treatments for Helicobacter pylori colonization, presence or degree of inflammation, atrophy or intestinal metaplasia at the end-point. CONCLUSION: In this study, GERD healing rates following rabeprazole 20 mg once daily were equivalent to those obtained with omeprazole 20 mg once daily. Both treatments resulted in a comparable relief of the frequency and intensity of heartburn associated with this disease, and both were well tolerated.

Comparison of rabeprazole 20 mg versus omeprazole 20 mg in the treatment of active duodenal ulcer: a European multicentre study.

BACKGROUND: Rabeprazole sodium is the newest member of a class of substituted benzimidazole molecules known as proton pump inhibitors. Other proton pump inhibitors have been shown to be effective in healing active duodenal ulcer. METHOD: This randomized, double-blind, multicentre study, conducted at 25 European sites, compared the efficacy and tolerability of rabeprazole and omeprazole in patients with active duodenal ulcers. One hundred and two patients with active duodenal ulcer received rabeprazole 20 mg and 103 patients omeprazole 20 mg once daily for 2 or 4 weeks, with ulcer healing monitored by endoscopy. RESULTS: After 2 weeks, complete ulcer healing was documented in 69% of patients given rabeprazole 20 mg and in 62% of patients given omeprazole 20 mg (N.S.). After 4 weeks, healing rates were 98% in the rabeprazole group and 93% in the omeprazole group (P = 0.083). Rabeprazole-treated patients had significantly greater improvement in daytime pain symptom relief than those treated with omeprazole at the conclusion of the study (P = 0.038). Both drugs were well tolerated over the 4-week treatment period. Mean changes from baseline to end-point in fasting serum gastrin were significantly greater in the rabeprazole group, but at end-point mean values were well within normal limits for both groups. No clinically meaningful changes or other between-group differences were observed in laboratory parameters. CONCLUSION: In this study, rabeprazole produced healing rates equivalent to omeprazole at weeks 2 and 4, and provided significantly greater improvement in daytime pain. Both treatments were well tolerated.

Rabeprazole produces rapid, potent, and long-acting inhibition of gastric acid secretion in subjects with Helicobacter pylori infection.

AIM: To compare acid inhibiting activity and duration of action of different doses of rabeprazole, a substituted benzimidazole characterized as a highly potent and irreversible H+, K+-ATPase inhibitor, administered for 7 days to subjects infected with Helicobacter pylori. METHODS: A total of 38 subjects (mean age 39.3 years) were enrolled in a single-centre, double-blind, randomized, crossover study. All subjects were confirmed positive for H. pylori by 14C urea breath test and ELISA serologies. Subjects were divided into two groups of 19 to receive two doses of rabeprazole, either 5 and 20 mg or 10 and 40 mg, and placebo, given in random order daily in the morning for 7 days. Peptone-stimulated acid, pH, and gastrin measurements were made for 24 h after the 1st dose and for 48 h after the 7th dose. RESULTS: Peptone-stimulated acid secretion rates were decreased from 12.5 to 6.7, 4.0, 1.5, and 0.26 h after initial 5, 10, 20, and 40 mg doses, respectively; to 7.3, 4.3, 2.1, and 1.2 mmol/h 23 h after the initial dose; and to 2.4, 2.6, 0.6, and 0.8 mmol/h 23 h after the 7th dose. After 48 h, stimulated acid secretion had recovered less than 40% for all treatment groups compared to placebo. Median intragastric pH also increased from 2.0 with placebo to 4.9, 6.2, 6.6 and 6.9 during the 24-h period after the 7th dose of 5, 10, 20, and 40 mg. The 20 mg dose of rabeprazole produced equivalent acid inhibition to the 40 mg dose with less increase in plasma gastrin. CONCLUSION: Rabeprazole in doses from 5 to 40 mg was a highly effective inhibitor of gastric acid secretion in subjects infected with H. pylori. The inhibition was rapid, dose-related, and long-acting, with less than 50% recovery of acid by 48 h after the 7th dose. The optimal acid inhibitory dose in these subjects appeared to be 20 mg daily, however 5 mg and 10 mg doses produced potent inhibition of gastric acid secretion.