Gaithersburg, MD- On Wednesday, June 13, the FDA's Circulatory Systems Devices Panel voted to recommend the Edwards SAPIEN transcatheter aortic valve for clinical approval in high-risk surgical aortic valve replacement candidates. Since November of 2011, SAPIEN has been approved for use only in patients deemed inoperable. However, if the FDA opts to heed the panel's recommendation for approval, the patient population eligible for SAPIEN will expand considerably.
While concerns about stroke, paravalvular leak, aortic insufficiency, and atrial fibrillation associated with transcatheter aortic valve replacement (TAVR) remain, at the end of the day, the 12-member, multidisciplinary panel voted decisively in favor of recommending SAPIEN’s approval. Specifically, the panel supported the clinical reality of TAVR for high risk surgical patients by voting 10 to 2 on safety, 12 to 0 on effectiveness, and 11 to 0 with one abstention that the technology’s benefits outweigh the risks for this specific patient population. Moreover, the recommended approval introduces the transapical approach into clinical practice for patients with complex anatomy deemed unfit for transfemoral access by an institution’s heart team.
This strong support for SAPIEN’s approval stems from positive results of the PARTNER Trial Cohort A, which randomized patients to TAVR or surgical aortic valve replacement (SAVR). At one year, the TAVR group’s mortality rate was slightly lower than SAVR group (24.2 versus 26.8 percent). This data therefore supported the clinical efficacy of TAVR, since it met predefined non-inferiority benchmarks compared to surgical aortic valve replacement. In addition, the transcatheter approach offers patients additional benefits, including:
- Earlier functional recovery with associated reduced hospital length of stay
- Improved 30-day NYHA class
- Six-minute walk distance
- Quality of life measures.
Despite positive clinical results, concerns over neurological complications remain for continued access patients.
Nevertheless, members of the panel raised concerns over procedural complications associated with TAVR therapy, including patients’ increased stroke and vascular event rates as compared to SAVR. At one year, patients receiving TAVR showed double the stroke rate of patients treated with standard SAVR (8 versus 4 percent). Aortic insufficiency, present in 60 percent of the trial’s TAVR patients at one year, also underscores the need for scans of cerebral infarction post-TAVR. Further clarification on the true risk parameters of stroke, vascular complications, and aortic insufficiency will need to be explored through post-market research studies, especially within the continued access arm of the PARTNER trial.
In addition, reduction of risks associated with these complications will largely depend on appropriate patient selection, follow-up, and innovation in adjunct technologies. In clinical practice, it will be critical for physicians to mitigate stroke and vascular complications by mandating appropriate antithrombotic regimens and developing specific procedural protocols on valve positioning. Continued innovation on embolic protection devices to capture loosened plaque during device implantation may also decrease this stroke risk.
Besides discussion of procedural complications in clinical practice, a presentation by the FDA called into question variations in crossover data between trial sites. Some major concerns included:
- Failed treatment
- Concomitant operations
- Time delay between randomization and procedure.
A major topic of discussion also centered on interpretation of data for continued access patients treated after conclusion of the PARTNER trial, as well as on the discrepancy between survival rates related to gender differences; trial results showed that females demonstrated a higher survival rate at one year than did males.
FDA panel expresses full support to expand SAPIEN device for high risk surgical candidates, contingent upon heart team approach, informed patient consent.
Although many questions remain unanswered and will need to be addressed through post-market follow-up, the panelists were almost unanimous in supporting the reasonable assurance of TAVR in terms of safety and efficacy when compared to surgical aortic valve replacement. Compared to the device panel in November of 2011, the question and answer session between device sponsors, such as Drs. Craig Smith and Martin Leon, and FDA panelists ran much more smoothly and conversationally than the more heated debate around SAPIEN’s candidacy for non-surgical candidates the previous year.
Of the two panelists who voted “no” on the safety issue of TAVR, Dr. Somberg stated, “I think this is a very good technology, and it gives us an alternative to AVR surgery, and I’m sure the device will continue to get better.” With the panel recommendation backing the clinical expansion of the device for high risk surgical candidates, the SAPIEN transcatheter valve has a favorable chance of gaining FDA approval in the next year. Although the potential FDA approval of TAVR may potentially cannibalize the aortic valve market, at the same time, it will expand the potential pool of patients able to receive treatment since 30 to 50 percent of patients with severe aortic stenosis remain untreated.
Emphasis on a heart team approach to patient selection and informed patient consent will similarly be critical issues of discussion to regulate the careful introduction of the device into the market. One panelist raised the question of patient selection. Although patients in the PARTNER trial are required to be screened and approved by four interventional cardiologists and four cardiac surgeons, it remains to be seen whether clinical practice will follow these strict guidelines in expanding TAVR only to appropriate high risk surgical candidates. Undoubtedly though, the role of the cardiac surgeon with experience performing high risk SAVR will be integral in the multidisciplinary heart team approach to TAVR.
Finally, FDA panelists agreed that, as TAVR emerges as an alternative to SAVR, it will be critical for physicians to introduce transcatheter valve treatment to patients under a shared decision making framework, in which patients should receive full disclosure and the benefits and potential complications associated with the device. As such, potential expansion of SAPIEN into the commercial market will necessitate that the FDA and Edwards Lifesciences ensure a measured process for device roll-out adverse events and optimize patient outcomes. Moving forward, Technology Insights will continue to track this potential for SAPIEN’s clinical expansion in order to keep hospital administrators and physicians abreast of key developments in this space.