A panel of experts today marginally voted to expand indications for all Medtronic (NYSE:MDT) pulse generators already on the market, adding labeling to treat patients at risk of developing new or worsened heart failure due to their need for right ventricular pacing.
The Circulatory System Devices Panel of the FDA’s Medical Devices Advisory Committee voted 4 to 3, with 1 abstention, that the benefits of programming patients for bi-ventricular pacing using Medtronic pulse generators outweighed the risks.
Panelists were unanimous that these devices were effective when programmed for bi-ventricular pacing, and voted 6 to 1 that they are safe.
The expanded indication, which Medtronic earlier this year announced it would pursue, applies to all of the company’s market-cleared cardiac resynchronization therapy pacemaker and cardiac resynchronization therapy defibrillator devices. Expanded indication was supported by the medtech giant’s BLOCK HF trial.
The BLOCK HF study aimed to demonstrate that heart failure patients programmed for bi-ventricular pacing lived longer, notched fewer urgent care visits and experienced significant increase in left ventricular end systolic volume index, as compared with patients programmed for right ventricular pacing.
Medtronic’s CRT-P devices are currently approved for use in patients with marked-to-severe heart failure. The company’s CRT-D devices are currently approved for patients at risk of developing life-threatening ventricular arrhythmias and who have either mild or severe heart failure.
The Medtronic pulse generators in question include both those with defibrillation capabilities and those without, and both types require implantation of at least a right ventricular and a left ventricular lead in order for sensing and pacing to work. The RV lead used with a CRT-D device can also deliver high voltage energy. Clinicians have discretion in whether to implant a right atrial lead for both devices.
While the prospective, multi-site, randomized, double-blinded, parallel-controlled BLOCK HF met its primary objective, the FDA had questions about the clinical meaning of increase in left ventricular end systolic volume index demonstrated by the study. LVESVI events accounted for more than half of the primary endpoint events in the BLOCK HF analysis, the agency noted in its executive summary posted ahead of the meeting.
The FDA questioned the significance of a change in LVESVI, because an increased LVESVI does not seem to strongly predict future heart failure urgent care events or death, today’s panelists said. And, when LVESVI is excluded from an exploratory analysis of BLOCK HF’s primary objective, the magnitude of benefit observed is reduced.
The panel will be asked to comment on the clinical meaning of an increase of greater than or equal to 15% LVESVI and the impact of LVESVI events on the success of the study.