A Food & Drug Administration panel said the risks of implanting cardiac resynchronization therapy defibrillators into patients suffering from milder forms of heart failure may not be worth the benefit on the open marketplace, even though Boston Scientific Corp. (NYSE:BSX) provided sound evidence of the devices’ effectiveness in its Madit-CRT study last fall.
In materials released ahead of its March 18 meeting, the regulatory agency said that the Natick, Mass.-based medical device giant met the basic goals of the massive 1,800-plus patient study by proving that the company’s therapy was effective in reducing heart failure events.
BSX goes before the the FDA’s circulatory systems devices panel Thursday to press its case for the expanded indication. The panel will decide if the company provided enough evidence to convince regulators that the devices are effective in treating all types of heart failure. Boston Scientific’s current indication is for patients diagnosed with New York Heart Assn. Class III or Class IV heart failure, classified as the most severe cases.
An expanded indication could be a big win for BSX.
Although the panel said the treatment showed positive results in the study, it was less certain about the overall benefits to a wider patient population.
“FDA is concerned that the cohort of patients enrolled into the study might not be entirely representative of all NYHA Class I-II cardiomyopathy patients,” the panel wrote. “More specifically, patients enrolled in the trial are not as healthy as typical NYHA Class I and NYHA Class II patients. Approximately 40 percent of the patients were previously hospitalized for heart failure, and 10 percent of the patients were previously NYHA Class III-IV greater than three months prior to enrollment. As a result, FDA is concerned that the reduction in all-cause mortality and heart failure hospitalization events might be less significant when CRT-D therapy is used in a commercially available setting, especially in patients who were not previously hospitalized for heart failure.”
The panel also said that the study failed to show that patients with Class I heart failure saw a greater reduction in heart failure events than patients with more severe, but still technically mild, Class II heart failure.
“This difference between NYHA Class I and NYHA Class II subjects might be due to the small sample size of NYHA Class I subjects or might be a result of the functional status itself,” the panel wrote. “In general, healthier patients are less likely to have heart failure events, and therefore CRT-D therapy is less likely to provide a reduction in the heart failure event rate as compared to less healthy NYHA Class II patients.”
And the panel questioned whether implanting devices into the Class I patient population was worth the risk of possible complications related to the surgery.
“Although the magnitude of this study was substantial for a device-based therapy, there still appear to be some remaining unanswered questions regarding the risk/benefit ratio of CRT-D therapy, especially in NYHA Class I patients that were under-represented in the MADIT-CRT study.”
Boston Scientific proposed to the agency that it will contact the approximately 585 patients who have been implanted with the device and fall into the category of less severe heart failure, to request participation in a post-approval study.
While no new patients would be implanted, the existing patients would be followed for two more years to provide a better assessment of the long term benefits.
BSX spokesman Dave Knutson told MassDevice that the company wouldn’t speculate about which way the panel is leaning, based on the report.
“We feel like we have a solid presentation to go in front of the panel with,” Knutson said. “Our data was very strong.”
Speculation about the market opportunity represented by an expanded indication is also premature, he added.
“We don’t have a solid answer that. If it’s full indication, it’s one number and if it’s Class II patients only, it’s another number,” he explained.
There have been varying reports on the patient population an expanded indication could serve, of anywhere from 5 million to 22 million.
Knutson said those numbers are wildly inflated.
“Even millions is pushing it,” he said, but still emphasized the potential impact on Boston Scientific as “substantial.”
The panel will make official recommendations March 18. Wall Street greeted the panel’s initial review positively, giving the company’s share price a 4.5 percent bounce on the news; investors seem to believe that the company will win the expanded indication.