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WASHINGTON, DC — There are mounting questions over whether bivalirudin (Angiomax, the Medicines Company) does indeed reduce major bleeding in the setting of contemporary primary PCI, compared with unfractionated heparin (UFH), without routine GPIIb/IIIa inhibition and when newer antiplatelet drugs are used. Presented at the American College of Cardiology 2014 Scientific Sessions earlier this week, controversial results from the large, single-center, randomized HEAT-PPCI trial showed no differences in bleeding but an increase in stent thrombosis with bivalirudin compared with heparin, when GPIIb/IIIa inhibitors were used just for bailout in both arms.

Two other trials, also presented at ACC 2014, appear to support those controversial findings: NAPLES III and BRAVE 4. A third trial, BRIGHT, presented in China, however, went in the other direction.

BRAVE 4 Results

BRAVE 4, like HEAT-PPCI, was a primary-PCI trial, designed to demonstrate that the “synergistic effects” of prasugrel (Effient, Lily/Daiichi-Sankyo) plus bivalirudin on ischemic events and bleeding complications would be superior to clopidogrel plus UFH in STEMI patients. Senior author Dr Stefanie Schulz(Deutsches Herzzentrum, Munich, Germany) and coauthors (the results were presented by Dr Gert Richardt [Herzzentrum Bad Segeberg, Germany]) chose an end point of net clinical outcome (defined as all-cause death, recurrent MI, unplanned revascularization of the infarct-related artery, definite stent thrombosis, stroke, or major bleeding at 30 days, using theHORIZONS-AMI definition). In one arm, a 60-mg loading dose of prasugrel plus an IV bolus of bivalirudin 0.75 mg/kg was followed by an infusion of 1.75 mg/kg. In the other, clopidogrel was given at 600 mg, then heparin was given as a 70- to 100-IU/kg bolus.

The investigator-initiated trial, conducted at three German centers, was originally designed to enroll over 1200 patients; the trial was stopped early, however, due to slow recruitment, with just 548 patients enrolled. As with HEAT-PPCI, GPIIb/IIIa inhibitors were used only when an operator decided they were needed with either drug. All but one patient underwent a transfemoral PCI.

At 30 days, there were no differences in the rate of primary composite end point. The secondary ischemic end point and secondary bleeding end point were also no different.

“We were not able to demonstrate a difference in net clinical outcome between prasugrel plus bivalirudin and clopidogrel plus heparin in STEMI patients,” Richardt concluded. “Neither the composite of ischemic complications nor bleeding were favorably affected by prasugrel plus bivalirudin. The results, however, must be interpreted [cautiously] in view of the premature termination of the trial.”

To heartwire , study coauthor Dr Robert Byrne noted that the actual event rate in the study was higher than the predicted event rate used for the power calculations in the study design, although these don’t fully compensate for the low patient numbers.

Given the premature discontinuation of the study, “the message we took was that when we use a primary composite end point, we didn’t see any difference between a newer antithrombotic approach with prasugrel and bivalirudin and an older combination, clopidogrel and heparin.”

In NAPLES III, Dr Carlo Briguori (Clinica Mediterranea, Naples, Italy) and colleagues compared bivalirudin with UFH in 830 elective transfemoral-PCI patients deemed to be at a high risk of bleeding (risk score >10). UFH was given in a bolus of 70 U/kg IV prior to the start of the PCI, followed by 20 U/kg if activated clotting times (ACTs) dropped below 250. Bivalirudin was given at 0.75 mg/kg IV prior to the procedure, followed by an infusion of 1.75 mg/kg per hour for the procedure duration, with additional 0.3 mg/kg if ACTs dropped below 250.

For the primary end point of in-hospital major bleeding (defined according to REPLACE 2 criteria) there were no differences between groups, including no differences by entry-site or non–entry-site bleeds, and no differences using different bleeding definitions. Major and minor bleeds combined were also no different between groups. For a range of secondary end points, including MI, stent thrombosis, and revascularization at both 30 days and one year, no differences emerged.

“In patients at high risk of bleeding undergoing elective PCI through the femoral approach, the use of bivalirudin does not reduce the rate of in-hospital major bleeding compared with UFH,” Briguori concluded.

Entry-site bleeding—seen in two and seven UFH and bivalirudin-treated patients, respectively “still represents an important issue,” he added. “A radial approach should be routinely used in this subgroup of patients.”

BRIGHTer News From China

Speaking with heartwire earlier this week about HEAT-PPCI,Dr Gregg Stone (Columbia University, New York, NY) emphasized that he did not think the results of any single-center randomized trial should inform the guidelines. “They should just be hypothesis-generating,” he said.

“There have been three large multicenter trials testing bivalirudin against heparin or heparin and GPIIb/IIIa inhibitors,” and these have all supported a lower risk of bleeding with bivalirudin.

Stone also flagged another large, “high-quality study” that he only learned about the previous week, while chairing a session at the China Interventional Therapeutics meeting in Shanghai.

According to a copy of the slide set obtained by heartwire , BRIGHT trial enrolled 2194 patients at 82 sites, comparing bivalirudin with heparin alone or heparin plus GPIIb/IIIa inhibitors. At 30 days, net adverse cardiovascular results were significantly reduced in the bivalirudin vs UFH/GPIIb/IIIa-inhibitor arms and narrowly missed being statistically significantly reduced in the bivalirudin vs UFH-monotherapy arms. A similar pattern was seen for all bleeding events, with 50% to 60% reductions in the bivalirudin-treated patients vs the heparin monotherapy and heparin/GPIIb/IIIa-inhibitor groups (p of 0.041 and 0.001, respectively).

The reductions in bleeding compared with both heparin arms are much more “consistent with what we’ve seen in EuroMAX , HORIZONS-AMI , and the registry series,” Stone said.

Why the Bleeds?

Stone, to heartwire , emphasized a point he also made during the HEAT-PPCI trial, that he did not believe the bivalirudin-treated patients were adequately dosed and questioned whether that dose was adjusted for renal insufficiency. One indicator of suboptimal dosing, he said, was the high use of bailout GPIIb/IIIa-inhibitors in HEAT: 13.5% in the bivalirudin-treated patients and 15.5% in the heparin-treated group.

By way of comparison, bailout GPIIb/IIIa inhibitor use was 3% in the prasugrel/bivalirudin group and 6% in the clopidogrel/heparin group in BRAVE 4. It was just 0.5% and 1.3% for the bivalirudin and UFH groups, respectively, in NAPLES III, although that lower use is to be expected in an elective-angioplasty population.

To heartwire , Byrne agreed that the ACC trials have raised questions about the bleeding advantage of bivalirudin in the contemporary PCI setting but stressed that it’s important with all of these trials to focus on the primary outcomes.

That said, “When you look at bleeding in BRAVE 4, as a secondary end point, we also didn’t see a difference.” One explanation, aside from the discretionary use of GPIIb/IIIa inhibitors, may be the use of more potent ADP-receptor antagonists, prasugrel and ticagrelor (Brilinta, AstraZeneca), which may “cancel out the bleeding benefit” of bivalirudin in modern-day PCI. Of note, clopidogrel was used in almost 100% of patients in BRIGHT.

Byrne says most operators at his institution are primarily using heparin, not bivalirudin, although they’ve only just stopped randomizing patients into BRAVE 4. “We are more comfortable with the lower doses of heparin based on ISAR REACT 3A ,” he noted. Byrne and his colleagues are also already enrolling patients into ISAR-REACT 5 , a 4000-patient trial randomizing ACS patients to heparin plus either ticagrelor or prasugrel. This is another investigator-initiated trial that Byrne notes neither drug maker was interested in funding.

Byrne, Richardt, and Briguori all disclosed having no conflicts of interest in their presentations. Stone was the PI for HORIZONS-AMI, for which he disclosed consulting fees and grant support from the Medicines Company, and ACUITY, for which he disclosed both consulting and lecturing fees. He currently discloses consulting fees/honoraria from Reva, Guided Delivery Systems, Velomedix, Osprey, Inspire MD, Miracor, CSI, Eli Lilly/Daiichi Sankyo, and Boston Scientific; holding a partnership/principal in Access Closure, Biostar I and II funds, Micardia, VNT, Medfocus I, II, and Accelerati funds, Arstasis, and Caliber; and research grants from InfraReDx and TherOx.