Cost-effectiveness analysis: cardiovascular benefits of proton pump inhibitor co-therapy in patients using aspirin for secondary prevention

Cost-Effectiveness of Vonoprazan Compared With Proton Pump Inhibitors in Patients Taking Low-Dose Aspirin for Secondary Prevention of Cardiovascular Events in Japan

BACKGROUND

Low-dose aspirin (LDA) is used to prevent recurrent cardiovascular (CV) events, but is associated with upper gastrointestinal (GI) bleeding; concomitant use of a proton pump inhibitor (PPI) reduces this risk. This study aimed to assess the cost-effectiveness of vonoprazan compared with PPIs (lansoprazole and esomeprazole) in patients taking LDA for secondary prevention of CV events.

METHODS AND RESULTS

A Markov simulation model was developed to predict the number of GI bleeding and acute CV events using 3 strategies (vonoprazan+LDA, esomeprazole+LDA, and lansoprazole+LDA), which were translated into quality-adjusted life-years (QALYs) and costs. Transition probabilities and utilities were derived from the results of published literature, and medical costs were based on the Japanese National Health Insurance fee table and claims databases in 2020. Outcomes were projected over 30 years starting at age 65 years and discounted at 2% annually. Expected costs with esomeprazole 20 mg, lansoprazole 15 mg and vonoprazan 10 mg were JPY 1,225,657, JPY 943,930, and JPY 1,059,510, respectively. The QALY gain for vonoprazan vs. esomeprazole was 0.35, thus vonoprazan was dominant against esomeprazole. The QALY gain for vonoprazan vs. lansoprazole was 0.29 and the incremental cost-effectiveness ratio (ICER) was JPY 398,551, thus, vonoprazan was more cost-effective than lansoprazole.

CONCLUSIONS

Vonoprazan is dominant or cost-effective compared with esomeprazole and lansoprazole in patients taking LDA for secondary prevention of CV events.

Aspirin Use in Secondary Cardiovascular Protection and the Development of Aspirin-Associated Erosions and Ulcers

Aspirin for secondary cardiovascular disease prevention is well established, but treatment discontinuation, often because of gastrointestinal mucosal injury or symptoms, can lead to increased risk for cardiovascular events. Proton pump inhibitor therapy is recommended for aspirin-treated patients at gastrointestinal risk. PA32540 [enteric-coated aspirin (EC-ASA) 325 mg + immediate-release omeprazole 40 mg] was compared with EC-ASA 325 mg alone once daily for 6 months in 2 duplicate, randomized double-blind trials in gastrointestinal-risk patients taking aspirin for ≥3 months for secondary prevention. In this post hoc analysis, we determined the prevalence of endoscopic upper gastrointestinal ulcers at screening and whether baseline endoscopic gastric erosions impacted subsequent ulcer development. At the screening endoscopy, 6% of subjects had upper gastrointestinal ulcers (not eligible for randomization) and 40% had gastric erosions. Conditional logistic regression modeling showed that baseline gastric erosions are significantly associated with endoscopic gastric ulcer development (OR = 2.12, 95% confidence interval, 1.26-3.57). In subjects with baseline gastric erosion, 4.2% of PA32540-treated versus 13.0% of EC-ASA-treated subjects (P = 0.001) subsequently developed endoscopic gastric ulcers. These data suggest that gastric injury predisposes to gastric ulcer development when taking EC-ASA, and exposure to immediate-release omeprazole in the presence of aspirin therapy significantly reduces the likelihood of progressing to gastric ulcers.

Cost Effectiveness of Gastroprotection with Proton Pump Inhibitors in Older Low-Dose Acetylsalicylic Acid Users in the Netherlands

Purpose

The present study aimed to assess the cost effectiveness of concomitant proton pump inhibitor (PPI) treatment in low-dose acetylsalicylic acid (LDASA) users at risk of upper gastrointestinal (UGI) adverse effects as compared with no PPI co-medication with attention to the age-dependent influence of PPI-induced adverse effects.

Methods

We used a Markov model to compare the strategy of PPI co-medication with no PPI co-medication in older LDASA users at risk of UGI adverse effects. As PPIs reduce the risk of UGI bleeding and dyspepsia, these risk factors were modelled together with PPI adverse effects for LDASA users 60–69, 70–79 (base case) and 80 years and older. Incremental cost-utility ratios (ICURs) were calculated as cost per quality-adjusted life-year (QALY) gained per age category. Furthermore, a budget impact analysis assessed the expected changes in expenditure of the Dutch healthcare system following the adoption of PPI co-treatment in all LDASA users potentially at risk of UGI adverse effects.

Results

PPI co-treatment of 70- to 79-year-old LDASA users, as compared with no PPI, resulted in incremental costs of €100.51 at incremental effects of 0.007 QALYs with an ICUR of €14,671/QALY. ICURs for 60- to 69-year-old LDASA users were €13,264/QALY and €64,121/QALY for patients 80 years and older. Initiation of PPI co-treatment for all Dutch LDASA users of 60 years and older at risk of UGI adverse effects but not prescribed a PPI (19%) would have cost €1,280,478 in the first year (year 2013 values).

Conclusions

PPI co-medication in LDASA users at risk of UGI adverse effects is generally cost effective. However, this strategy becomes less cost effective with higher age, particularly in patients aged 80 years and older, mainly due to the increased risks of PPI-induced adverse effects.

The budget impact of using enteric-coated aspirin 325 mg + immediate-release omeprazole 40 mg to prevent recurrent cardiovascular events

OBJECTIVE

Aspirin (acetylsalicylic acid; ASA) is commonly used for secondary prevention of cardiovascular (CV) events, but may be associated with gastrointestinal (GI) adverse events, which can reduce adherence. Use of ASA co-therapy with proton pump inhibitors in patients at risk may be suboptimal. PA32540 (Yosprala™) is a coordinated-delivery tablet combining EC-ASA 325 mg and immediate-release omeprazole 40 mg. The objective of this flexible budget impact model was to project the financial consequences of introducing PA32540 325 mg/40 mg to prevent recurrent CV events, while reducing ASA-associated GI events in US adults.

METHODS

A Markov Model was employed to estimate health state transitions associated with ASA 75-325 mg, ASA 75-325 mg + generic delayed-release omeprazole 40 mg, PA32540, or clopidogrel 75 mg to prevent recurrent CV events. Health states included ulcers, GI bleeding, CV events, and death. Model inputs included demographics, treatment dosages, treatment costs, adverse GI and CV events, and premature death. Data from peer-reviewed literature and censuses enabled appropriate allocation of CV and GI disease prevalence and mortality. The PA32540 non-adherence rate was conservatively set at 20%. PA32540 market share was set to 50%.

RESULTS

The model projected annual savings of $81.0 million to $190.9 million within 1-5 years after PA32540 introduction to the plan, which included 134,558 members at risk for recurrent CV events. These values translate into savings of $602 (year 5) to $1,419 (year 1) per patient per year, and $81 (year 5) to $191 (year 1) per member per year. These values were robust to variations in parameters under a deterministic sensitivity analysis.

CONCLUSION

PA32540 use to prevent recurrent CV events was associated with cost reductions in each year examined with the model. From a health plan perspective, PA32540 is likely to have a net overall effect, resulting in significant cost savings.

Upper Gastrointestinal Toxicity Associated With Long-Term Aspirin Therapy: Consequences and Prevention

Antiplatelet therapy represents a fundamental part of preventive management for patients who are at risk of a secondary cardiovascular disease (CVD) event. In most cases, the antiplatelet regimen is based on low-dose aspirin, a drug that is highly effective in reducing the incidence of CVD events, but is associated with a substantial risk of gastrointestinal (GI) toxicity. The dyspeptic symptoms, which can result from aspirin administration, and which may occur with or without associated ulceration and bleeding, may lead patients to discontinue therapy, thus increasing their CVD risk. For patients in whom aspirin is indicated and who are deemed to be at increased risk of upper GI events, concomitant therapy with a proton pump inhibitor (PPI) is currently recommended. These agents are highly effective in reducing the upper GI lesions associated with aspirin therapy and have been associated with increased aspirin adherence. However, widespread under-prescribing of PPIs and potential noncompliance with their use means that substantial numbers of patients are at unnecessary risk of upper GI toxicity and-if aspirin therapy is discontinued-CVD events. Provision of aspirin and an immediate-release PPI as a coordinated-delivery combination tablet has been shown to both reduce the risk of gastric ulcer formation and improve patient compliance. This strategy, which may ultimately reduce the incidence of CVD outcomes because of the associated reduction in GI symptoms and the potential for greater patient adherence to aspirin, warrants further investigation under both randomized controlled conditions (explanatory trials), and in real-life settings (pragmatic trials).

Long-Term Safety of a Coordinated Delivery Tablet of Enteric-Coated Aspirin 325 mg and Immediate-Release Omeprazole 40 mg for Secondary Cardiovascular Disease Prevention in Patients at GI Risk

Introduction

In two, 6‐month, randomized, double‐blind Phase 3 trials, PA32540 (enteric‐coated aspirin 325 mg and immediate‐release omeprazole 40 mg) compared to aspirin alone was associated with fewer endoscopic gastric and duodenal ulcers in patients requiring aspirin therapy for secondary cardiovascular disease (CVD) prevention who were at risk for upper gastrointestinal (UGI) events.

Aims

In this 12‐month, open‐label, multicenter Phase 3 study, we evaluated the long‐term cardiovascular and gastrointestinal safety of PA32540 in subjects who were taking aspirin 325 mg daily for ≥3 months for secondary CVD prevention and were at risk for aspirin‐associated UGI events. Enrolled subjects received PA32540 once daily for up to 12 months and were assessed at baseline, month 1, month 6, and month 12.

Results

The overall safety population consisted of 379 subjects, and 290 subjects (76%) were on PA32540 for ≥348 days (12‐month completers). Adverse events (AEs) caused study withdrawal in 13.5% of subjects, most commonly gastroesophageal reflux disease (1.1%). Treatment‐emergent AEs occurred in 76% of the safety population (11% treatment‐related) and 73% of 12‐month completers (8% treatment‐related). The most common treatment‐related AE was dyspepsia (2%). One subject had a gastric ulcer observed on for‐cause endoscopy. There were five cases of adjudicated nonfatal myocardial infarction, one nonfatal stroke, and one cardiovascular death, but none considered treatment‐related.

Conclusions

Long‐term treatment with PA32540 once daily for up to 12 months in subjects at risk for aspirin‐associated UGI events is not associated with any new or unexpected safety events.

Proton Pump Inhibitors in Cardiovascular Disease: Drug Interactions with Antiplatelet Drugs

Aspirin and P2Y₁₂ receptor antagonists are widely used across the spectrum of cardiovascular diseases. Upper gastrointestinal complications, including ulcer and bleeding, are relatively common during antiplatelet treatment and, therefore, concomitant proton pump inhibitor (PPI) treatment is often prescribed.PPIs provide gastroprotection by changing the intragastric milieu, essentially by raising intragastric pH. In recent years, it has been heavily discussed whether PPIs may reduce the cardiovascular protection by aspirin and, even more so, clopidogrel. Pharmacodynamic and pharmacokinetic studies suggested an interaction between PPIs and clopidogrel, and subsequent clinical studies were conducted to evaluate the clinical impact of this interaction. More recently, it was reported that PPIs may also attenuate the antiplatelet effect of aspirin. This may be clinically important, because a fixed combination of aspirin and a PPI (esomeprazole) has recently been approved and because aspirin is the most widely used drug in patients with cardiovascular disease. The antiplatelet effect of the new P2Y₁₂ receptor antagonists, ticagrelor and prasugrel, seems less influenced by PPI co-treatment.Given the large number of patients treated with antithrombotic drugs and PPIs, even a minor reduction of platelet inhibition potentially carries considerable clinical impact. The present book chapter summarizes the evidence regarding the widespread use of platelet inhibitors and PPIs in combination. Moreover, it outlines current evidence supporting or opposing drug interactions between these drugs and discusses clinical implications.

Cost-Effectiveness of Proton Pump Inhibitor Co-Therapy in Patients Taking Aspirin for Secondary Prevention of Ischemic Stroke

BACKGROUND

Low-dose aspirin (ASA) is effective for secondary prevention of ischemic stroke but can increase the risks of hemorrhagic stroke, upper gastrointestinal bleeding (UGIB), and dyspepsia. Prophylactic administration of proton pump inhibitors (PPIs) reduces the risks of these digestive symptoms. We investigated the cost effectiveness of adding a PPI to ASA therapy for ischemic stroke patients in Japan.

METHODS

A Markov state-transition model was developed to compare the cost effectiveness of ASA monotherapy with ASA plus PPI co-therapy in patients with histories of upper gastrointestinal ulcers and ischemic stroke. The model takes into account ASA adherence rate and adverse effects due to ASA, including hemorrhagic stroke and UGIB. The analysis was performed from the perspective of healthcare payers in 2013.

RESULTS

In the base case, total life-years by PPI co-therapy and monotherapy were 16.005 and 15.932, respectively. The difference in duration of no therapy (no ASA or PPI) between the therapies was 558.5 days, which would prevent 30.3 recurrences of ischemic stroke per 1000 person-years. The incremental cost-effectiveness ratio of PPI co-therapy relative to monotherapy was ¥1,191,665 (US$11,458) per life-year gained. In a one-way sensitivity analysis, PPI co-therapy was consistently cost effective at a willingness to pay of ¥5,000,000 (US$48,077) per life-year gained. In a probabilistic sensitivity analysis, the probability that PPI co-therapy was cost effective was 89.74% at the willingness to pay.

CONCLUSIONS

Co-therapy with ASA plus PPI appears to be cost-effective compared with ASA monotherapy. The addition of PPI also appeared to prolong the duration of ASA therapy, thereby reducing the risk of ischemic stroke.

The effects of proton pump inhibition on patient-reported severity of dyspepsia when receiving dual anti-platelet therapy with clopidogrel and low-dose aspirin: analysis from the Clopidogrel and the Optimization of Gastrointestinal Events Trial

BACKGROUND

Dual anti-platelet therapy with clopidogrel and low-dose aspirin increases the risk for gastrointestinal clinical events. Omeprazole has been shown to significantly reduce these events without compromising cardiovascular safety in patients treated with dual anti-platelet therapy. Whether or not omeprazole improves patient-reported outcomes is undetermined.

AIM

To assess the impact of prophylactic omeprazole with background dual anti-platelet therapy on patient-reported symptoms of dyspepsia compared to placebo.

METHODS

We analysed results of the Severity of Dyspepsia Assessment questionnaires collected in the Clopidogrel and the Optimization of Gastrointestinal Events Trial.

RESULTS

Patient-reported outcome data from 3759 subjects were available for analysis. At 4 weeks, the mean scores of pain intensity and nonpain symptoms were lower in the omeprazole group (5.61 ± 0.17 vs. 6.40 ± 0.17, P = 0.001, and 10.61 ± 0.07 vs. 11.00 ± 0.07, P < 0.001 respectively). These differences were maintained at 24 weeks (5.91 ± 0.35 vs. 7.10 ± 0.37, P = 0.020 for pain intensity; 10.36 ± 0.12 vs. 10.93 ± 0.13, P = 0.001 for nonpain symptoms). After adjusting for covariates there were no statistically significant differences between the groups in the percent of patients with dyspepsia during follow-up.

CONCLUSIONS

In addition to reducing the risk of gastrointestinal bleeding, statistically significant benefits with prophylactic omeprazole use on both pain and nonpain symptoms were evident at 4 weeks and sustained through 24 weeks. The clinical significance of these overall results is unclear, but greater in patients with pain at baseline.

Randomised clinical trial: prevention of recurrence of peptic ulcers by rabeprazole in patients taking low-dose aspirin

BACKGROUND

Few studies have evaluated the effects of rabeprazole on low-dose aspirin (LDA)-induced gastroduodenal injuries.

AIM

To conduct a randomised, double-blind, triple-dummy, active-controlled, multicentre trial, named the PLANETARIUM study, to assess the efficacy, dose-response relationship and safety of rabeprazole for peptic ulcer recurrence in Japanese patients on long-term LDA therapy.

METHODS

Eligible patients had a history of endoscopically confirmed peptic ulcers and were receiving long-term LDA (81 or 100 mg/day) therapy for cardiovascular or cerebrovascular protection. Subjects were randomly segregated into three groups receiving rabeprazole 10 mg once daily (standard dose in Japan), rabeprazole 5 mg once daily, or teprenone (geranylgeranylacetone; mucosal protective agent commercially available in Japan) 50 mg three times per day as an active control. The primary endpoint was recurrence of peptic ulcers over 24 weeks.

RESULTS

Among 472 randomised subjects, 452 subjects (n = 151, 150, 151, respectively) constituted the full analysis set. The cumulative recurrence rates of peptic ulcers over 24 weeks in the 10- and 5-mg rabeprazole groups were 1.4% and 2.8%, respectively, both of which were significantly lower than that in the teprenone group (21.7%). The cumulative occurrence rate of bleeding ulcers over 24 weeks in the teprenone group was 4.6%, while bleeding ulcers were not observed in the 10- or 5-mg rabeprazole groups. Rabeprazole was well tolerated at both doses.

CONCLUSION

Rabeprazole prevents the recurrence of peptic ulcers with no evidence of a major dose-response effect in subjects on low-dose aspirin therapy.

One fifth of hospitalizations for peptic ulcer-related bleeding are potentially preventable

AIM: To calculate the proportion of potentially preventable hospitalizations due to peptic ulcer disease (PUD), erosive gastritis (EG) or duodenitis (ED).

METHODS: Retrospective cohort study using ICD-10 codes to identify all patients with upper gastrointestinal hemorrhage secondary to endoscopically proven PUD, EG or ED during the period from March 2007 to October 2010 in three major metropolitan hospitals in Melbourne, Australia. Patients were divided into “high risk” (those who would benefit from gastroprotection) and “not high risk” groups as defined by established guidelines. Mean Rockall score, transfusion requirement, length of stay, rebleeding rates, need for surgery and in-hospital mortality was compared between “high risk” and “not high risk” groups. Within the “high risk” group, those on gastroprotection and those with no gastroprotection were also compared.

RESULTS: Five hundred and seven patients were included for analysis of which 174 were classified as high risk. Median values of complete Rockall Score (5 vs 4, P = 0.002) and length of stay (5 d vs 4 d, P = 0.04) were higher in the high risk group but in-hospital mortality was lower (0.6% vs 3.9%, P = 0.03). 130 out of the 174 patients in the high risk group were not taking recommended gastroprotective therapy prior to hospitalization. Past history of PUD (OR = 3.7, P = 0.006) and clopidogrel use (OR = 3.2, P = 0.007) significantly predicted prescription of gastroprotective therapy. Using proton pump inhibitor protection rates of 50%-85% from published studies, an estimation of 13% to 22% of the total number of the hospitalizations due to PUD or EG/ED related bleeding may have been preventable.

CONCLUSION: Up to one fifth of all hospitalizations for bleeding secondary to PUD or EG/ED are potentially preventable.

Gastroprotection in low-dose aspirin users for primary and secondary prevention of ACS: results of a cost-effectiveness analysis including compliance

PURPOSE

Low-dose aspirin (ASA) increases the risk of upper gastrointestinal (GI) complications. Proton pump inhibitors (PPIs) reduce these upper GI side effects, yet patient compliance to PPIs is low. We determined the cost-effectiveness of gastroprotective strategies in low-dose ASA users considering ASA and PPI compliance.

METHODS

Using a Markov model we compared four strategies: no medication, ASA monotherapy, ASA+PPI co-therapy and a fixed combination of ASA and PPI for primary and secondary prevention of ACS. The risk of acute coronary syndrome (ACS), upper GI bleeding and dyspepsia was modeled as a function of compliance and the relative risk of developing these events while using medication. Costs, quality adjusted life years and number of ACS events were evaluated, applying a variable risk of upper GI bleeding. Probabilistic sensitivity analyses were performed.

RESULTS

For our base case patients using ASA for primary prevention of ACS no medication was superior to ASA monotherapy. PPI co-therapy was cost-effective (incremental cost-effectiveness ratio [ICER] €10,314) compared to no medication. In secondary prevention, PPI co-therapy was cost-effective (ICER €563) while the fixed combination yielded an ICER < €20,000 only in a population with elevated risk for upper GI bleeding or moderate PPI compliance. PPI co-therapy had the highest probability to be cost-effective in all scenarios. PPI use lowered the overall number of ACS.

CONCLUSIONS

Considering compliance, PPI co-therapy is likely to be cost-effective in patients taking low dose ASA for primary and secondary prevention of ACS, given low PPI prices. In secondary prevention, a fixed combination seems cost-effective in patients with elevated risk for upper GI bleeding or in those with moderate PPI compliance. Both strategies reduced the number of ACS compared to ASA monotherapy.

Multidisciplinary management strategies for acute non-variceal upper gastrointestinal bleeding

BACKGROUND

The modern management of acute non-variceal upper gastrointestinal bleeding is centred on endoscopy, with recourse to interventional radiology and surgery in refractory cases. The appropriate use of intervention to optimize outcomes is reviewed.

METHODS

A literature search was undertaken of PubMed and the Cochrane Central Register of Controlled Trials between January 1990 and April 2013 using validated search terms (with restrictions) relevant to upper gastrointestinal bleeding.

RESULTS

Appropriate and adequate resuscitation, and risk stratification using validated scores should be initiated at diagnosis. Coagulopathy should be corrected along with blood transfusions, aiming for an international normalized ratio of less than 2·5 to proceed with possible endoscopic haemostasis and a haemoglobin level of 70 g/l (excluding patients with severe bleeding or ischaemia). Prokinetics and proton pump inhibitors (PPIs) can be administered while awaiting endoscopy, although they do not affect rebleeding, surgery or mortality rates. Endoscopic haemostasis using thermal or mechanical therapies alone or in combination with injection should be used in all patients with high-risk stigmata (Forrest I-IIb) within 24 h of presentation (possibly within 12 h if there is severe bleeding), followed by a 72-h intravenous infusion of PPI that has been shown to decrease further rebleeding, surgery and mortality. A second attempt at endoscopic haemostasis is generally made in patients with rebleeding. Uncontrolled bleeding should be treated with targeted or empirical transcatheter arterial embolization. Surgical intervention is required in the event of failure of endoscopic and radiological measures. Secondary PPI prophylaxis when indicated and Helicobacter pylori eradication are necessary to decrease recurrent bleeding, keeping in mind the increased false-negative testing rates in the setting of acute bleeding.

CONCLUSION

An evidence-based approach with multidisciplinary collaboration is required to optimize outcomes of patients presenting with acute non-variceal upper gastrointestinal bleeding.

Cardiovascular and upper gastrointestinal bleeding consequences of low-dose acetylsalicylic acid discontinuation

It was the aim of this study to investigate whether low-dose acetylsalicylic acid (ASA) therapy for secondary cardiovascular prevention should continue, despite the risk of gastrointestinal bleeding. We aimed to make a clinically meaningful benefit-risk assessment regarding the cardiovascular and gastrointestinal consequences of ASA discontinuation.This case-control study usedThe Health Improvement Network UK primary care database to identify patients aged 50-84 years during 2000-2007 with a first ASA prescription for secondary cardiovascular prevention (N = 39,513). New cases of non-fatal myocardial infarction (MI)/coronary death (n = 1,222), ischaemic stroke (IS)/transient ischaemic attack (TIA) (n = 673) and upper gastrointestinal bleeding (UGIB) (n = 169) were identified after a mean follow-up of 3.2, 3.4 and 4.0 years, respectively. ASA discontinuers before the index date were identified. Attributable risks associated with ASA discontinuation were calculated and National Institute for Health and Clinical Excellence annual economic data were used to estimate healthcare costs. The cumulative incidences of non-fatal MI/coronary death, IS/TIA and UGIB among ASA discontinuers within the first year of follow-up were 17, 11 and 1.6 per 1,000 persons, respectively. This corresponds to eight extra cardiovascular events, and a reduction of 0.4 UGIB events per year compared with current ASA users. Extrapolating to the UK population aged over 50 years, avoiding discontinuation of ASA could prevent 12,786 coronary and 7,672 cerebrovascular events/year, at the expense of 1023 extra UGIB events, saving approximately £100 million/year. In conclusion, preventing patients with cardiovascular disease from discontinuing ASA could result in substantial clinical and economic gains.

Intragastric acidity and omeprazole exposure during dosing with either PA32540 (enteric-coated aspirin 325 mg + immediate-release omeprazole 40 mg) or enteric-coated aspirin 325 mg + enteric-coated omeprazole 40 mg - a randomised, phase 1, crossover study

BACKGROUND

Aspirin therapy is associated with adverse upper gastrointestinal effects. PA32540 is a coordinated-delivery tablet containing enteric-coated aspirin (EC-ASA) 325 mg and immediate-release (IR) omeprazole 40 mg. Immediate-release omeprazole (located in outer layer of tablet) is available for instantaneous dissolution rapidly after ingestion, while dissolution of the EC-ASA core is delayed until pH >5.5.

AIM

To compare the pharmacodynamic and pharmacokinetic effects of PA32540 (EC-ASA 325 mg + IR-omeprazole 40 mg) vs. enteric-coated (EC)-omeprazole 40 mg.

METHODS

This single-centre, open-label, randomised, two-way crossover study in healthy volunteers compared 7 days of once-daily dosing with PA32540 with 7 days of once-daily EC-ASA 325 mg + EC-omeprazole 40 mg dosed concomitantly. The primary endpoint was per cent time intragastric pH >4 over 24 h on Day 7. A key secondary endpoint was determination of the pharmacokinetics of omeprazole and salicylic acid.

RESULTS

Twenty-six subjects (mean age 29 years) were enrolled into the study. On Day 7, mean per cent time intragastric pH >4 was 50.6% for PA32540 and 57.6% for EC-omeprazole 40 mg (P = 0.004) and geometric least squares mean AUC0-24 for omeprazole was 1446 h*ng/mL for PA32540 and 2558 h*ng/mL for EC-omeprazole 40 mg. Day 7 median Tmax of omeprazole was 0.5 h for PA32540 and 1.25 h for EC-omeprazole 40 mg.

CONCLUSION

Total exposure to omeprazole from PA32540 was 57% of that from EC-omeprazole for the same dose amount (40 mg), while absolute difference in 24-h acid control was 7%. Omeprazole exposure and pH control with PA32540 appear similar to EC-omeprazole 20 mg.

Esomeprazole and aspirin fixed combination for the prevention of cardiovascular events

Low dose aspirin therapy plays a fundamental role in both the primary and secondary prevention of cardiovascular events. Although the evidence using low dose aspirin for secondary prevention is well-established, the decision to use aspirin for primary prevention is based on an evaluation of the patient’s risk of cardiovascular events compared to their risk of adverse events, such as bleeding. In addition to the risk of bleeding associated with long term aspirin administration, upper gastrointestinal side effects, such as dyspepsia often lead to discontinuation of therapy, which places patients at an increased risk for cardiovascular events. One option to mitigate adverse events and increase adherence is the addition of esomeprazole to the medication regimen. This review article provides an evaluation of the literature on the concomitant use of aspirin and esomeprazole available through February 2013. The efficacy, safety, tolerability, cost effectiveness, and patient quality of life of this regimen is discussed. A summary of the pharmacokinetic and pharmacodynamic interactions between aspirin and esomeprazole, as well as other commonly used cardiovascular medications are also reviewed. The addition of esomeprazole to low dose aspirin therapy in patients at high risk of developing gastric ulcers for the prevention of cardiovascular disease, significantly reduced their risk of ulcer development. Pharmacokinetic and pharmacodynamic studies suggested that esomeprazole did not affect the pharmacokinetic parameters or the antiplatelet effects of aspirin. Therefore, for those patients who are at a high risk of developing a gastrointestinal ulcer, the benefit of adding esomeprazole likely outweighs the risks of longer term proton pump inhibitor use, and the combination can be recommended. Administering the two agents separately may also be more economical. On the other hand, for those patients at lower risk of developing a gastrointestinal ulcer, both the additional risk and cost make the inclusion of a proton pump inhibitor unwarranted.

Inclusion of compliance and persistence in economic models: past, present and future

Economic models are developed to provide decision makers with information related to the real-world effectiveness of therapeutics, screening and diagnostic regimens. Although compliance with these regimens often has a significant impact on real-world clinical outcomes and costs, compliance and persistence have historically been addressed in a relatively superficial fashion in economic models. In this review, we present a discussion of the current state of economic modelling as it relates to the consideration of compliance and persistence. We discuss the challenges associated with the inclusion of compliance and persistence in economic models and provide an in-depth review of recent modelling literature that considers compliance or persistence, including a brief summary of previous reviews on this topic and a survey of published models from 2005 to 2012. We review the recent literature in detail, providing a therapeutic-area-specific discussion of the approaches and conclusions drawn from the inclusion of compliance or persistence in economic models. In virtually all publications, variation of model parameters related to compliance and persistence was shown to have a significant impact on predictions of economic outcomes. Growing recognition of the importance of compliance and persistence in the context of economic evaluations has led to an increasing number of economic models that consider these factors, as well as the use of more sophisticated modelling techniques such as individual simulations that provide an avenue for more rigorous consideration of compliance and persistence than is possible with more traditional methods. However, we note areas of continuing concern cited by previous reviews, including inconsistent definitions, documentation and tenuous assumptions required to estimate the effect of compliance and persistence. Finally, we discuss potential means to surmount these challenges via more focused efforts to collect compliance and persistence data.

Combining aspirin and proton pump inhibitors: for whom the warning bell tolls?

Aspirin and clopidogrel are well-known antiplatelet agents that are widely used across the spectrum of cardio- and cerebrovascular disease. Upper gastrointestinal complications, including ulcer and bleeding, are relatively common during antiplatelet treatment and, therefore, many patients are also treated with a proton pump inhibitor (PPI). PPIs exert gastroprotection by raising intragastric pH. In recent years, it has been heavily discussed whether PPIs may reduce the cardiovascular protection by aspirin and, even more so, clopidogrel. Initially, pharmacodynamic and pharmacokinetic studies suggested a considerable drug interaction between PPIs and clopidogrel, and subsequent clinical studies were conducted to evaluate the clinical impact of this interaction. More recently, it has been reported that PPIs may also attenuate the antiplatelet effect of aspirin. This is particularly interesting, because a fixed combination of aspirin and a PPI (esomeprazole) has been developed and is currently under approval. Given the large number of patients taking aspirin and PPIs, even a small attenuation of the antiplatelet effect of aspirin may have substantial clinical impact. The present editorial summarizes current evidence on this drug interaction and discusses potential clinical implications.