MIAMI. -- Daiichi Sankyo, Inc. and Eli Lilly and Company today announced new results of two retrospective, observational, comparative effectiveness studies of U.S. hospital data comparing rates of readmission for subsequent heart attack and initial hospitalization costs among patients with acute coronary syndromes (ACS) treated with a percutaneous coronary intervention (PCI) and antiplatelet therapy, including Effient® (prasugrel) or Plavix®(clopidogrel). The findings were presented at the 24th annual Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium. Sponsored by the Cardiovascular Research Foundation (CRF), TCT is the world's premier educational meeting specializing in interventional cardiovascular medicine.

The first study evaluated the rate of rehospitalization for acute myocardial infarction (AMI) and bleeding at both 30- and 90-days after discharge for ACS-PCI patients treated with Effient compared to Plavix.[1] Based on a cohort of 83,567 ACS-PCI patients in the PREMIER database, Effient-treated patients (n=9,404) had a significantly lower adjusted rate of rehospitalization for AMI than Plavix-treated patients (n=74,163) at 30 days (Odds Ratio [OR]: 0.89; p=0.047) and 90 days (OR: 0.90; p= 0.037) following ACS-PCI discharge. The adjusted rates of bleeding-related rehospitalization were not different between Effient- and Plavix-treated patients at 30 days (OR: 1.04; p=0.82) or 90 days (OR: 0.92; p=0.51) post-discharge. In the pivotal randomized control trial, TRITON-TIMI 38, the risk of serious bleeding was significantly higher with Effient versus Plavix (2.2 percent versus 1.7 percent, respectively).[2]

The second study evaluated use of healthcare resources by Effient-treated ACS-PCI patients compared to Plavix-treated patients during index hospitalization (hospitalization that qualified the patients for entry into the study), as measured by hospital costs.[3] Based on a cohort of 84,695 ACS-PCI patients in the PREMIER database, adjusted estimates of average hospitalization costs for patients receiving Plavix (n=75,224) or Effient (n=9,471) were $17,519 (+ or - $2,548) and $17,139 (+ or - $2,560) respectively – a cost savings of $380 (p<0.05) for Effient-treated patients during the index hospital stay. Results were consistent across subgroups by subtype of ACS (STEMI, NSTEMI, and unstable angina).

"In the current healthcare environment, it is important to understand the comparative effectiveness of antiplatelet therapies on rehospitalization rates for subsequent events, such as heart attacks, and index hospitalization costs associated with their use in the real-world setting," said lead study investigator Jay P. Bae, Ph.D., health economist, Health Outcomes Research, Global Health Outcomes, Eli Lilly and Company. "The findings of these studies expand on data from clinical studies and previous health outcomes research."

The studies were conducted using the PREMIER Perspective Database, a large U.S. database of drug utilization and other aggregate hospital data on more than 45 million inpatient discharges and 210 million hospital outpatient visits from U.S. acute care facilities, ambulatory surgery centers and clinics.[4] The PREMIER Perspective Database has been selected by the Centers for Medicare & Medicaid Services for measurement of hospital quality and is commonly used for outcomes research including studies published in top medical journals. The data presented at TCT evaluated non-randomized ACS-PCI patients hospitalized between July 2009 and June 2011. The study endpoints were pre-specified and the analyses were blinded and conducted by the PREMIER research team. The studies included ACS-PCI patients treated with Effient who were on label or Plavix-treated patients who would have been eligible for Effient treatment per the U.S. prescribing information (i.e., patients who fit the description of the indication in the U.S. FDA-approved Effient label).[1]

"The results from the PREMIER studies provide physicians with real-world insights into the use and effectiveness of Effient in ACS-PCI patients in the United States," said Xin Ye, Ph.D., Director, Health Economics & Outcomes Research, Daiichi Sankyo, Inc.

This study was adjusted for potential selection bias, including the following variables: patient age, sex, race, type of ACS diagnosis, comorbidities and details of intervention.

The studies were conducted by researchers at Lilly and the Premier Healthcare Alliance.

Assessment of Observed Rates of 30- and 90-Day Rehospitalization for AMI and Bleeding in Patients with ACS-PCI: Comparison of Effient and Plavix

The observed rates of 30- and 90-day rehospitalization due to AMI and 30- and 90-day bleeding-related rehospitalization rates among ACS-PCI patients treated with Effient or Plavix in a real-world U.S. hospital setting were also presented at TCT. At 30-days, the unadjusted AMI-related rehospitalization rates were significantly lower for Effient as compared to Plavix (3.9 percent and 4.7 percent, respectively; p<0.05). At 90-days, the unadjusted AMI-related rehospitalization rates were significantly lower for Effient as compared to Plavix (5.1 percent and 6.3 percent, respectively; p<0.05).

The unadjusted bleeding-related rehospitalization rate was 0.5 percent in Effient-treated patients compared to 0.8 percent in Plavix-treated patients at 30-days (p<0.05) and 0.8 percent in Effient-treated patients compared to 1.4 percent in Plavix-treated patients at 90-days (p<0.05) post-discharge.

Observed Mean Length of Stay, Hospitalization Costs and Bleeding Rates of ACS-PCI: Comparison of Effient and Plavix

The goal of this analysis was to compare observed mean length of stay, total costs and bleeding rates associated with the index hospitalization – hospitalization that qualified the patients for entry into the study – for ACS-PCI patients treated with Effient or Plavix. Across the entire study population, the unadjusted mean length of stay was 2.9 + or - 2.4 days for Effient-treated patients as compared to 3.5 + or - 4.4 days for Plavix-treated patients (p<0.05). The actual observed mean hospitalization costs for Effient-treated patients were $16,199 + or - $10,054 compared to $17,647 + or - $16,696 for Plavix-treated patients (p<0.05).

In the study, unadjusted rates of bleeding (defined as the presence of bleeding ICD-9 codes) were 2.2 percent and 3.3 percent in Effient- and Plavix-treated patients, respectively (p<0.05).

Unadjusted rates of transfusion were 1.2 percent and 3.1 percent in Effient- and Plavix-treated patients, respectively (p<0.05). Unadjusted rates of bleeding or transfusion were 3.2 percent and 5.7 percent in Effient- and Plavix-treated patients, respectively (p<0.05).

In the pivotal randomized control trial, TRITON-TIMI 38, the risk of serious bleeding was significantly higher with Effient versus Plavix (2.2 percent versus 1.7 percent, respectively).[2]

Limitations of the PREMIER Database Studies

Although significant demographic, clinical, treatment- and intervention-related data were used to adjust for potential bias in these studies, other unrecognized sources of bias may still exist in any non-randomized database study. For example, the PREMIER database did not include data on patient characteristics, such as blood pressure, height and weight. The lack of weight data is important, since weight is a predictor of risk for bleeding. The researchers plan to conduct additional quantitative analysis on potential sources of bias in the database.

Source: Eli Lilly and Company