UPDATE: Dec. 3, 2019: FDA on Monday reaffirmed its guidance that patient selection for Abiomed's Impella RP treatment can significantly influence patient outcomes, citing the latest post-approval study results for the right heart pump system.
In an update to a May letter to healthcare providers, the agency said post-approval study (PAS) results "continue to show" survival among the subgroup of PAS patients who would have qualified for premarket clinical studies is similar to the rate seen in premarket studies.
Specifically, 16 out of 22 patients in the post-approval study who would have met enrollment criteria for the premarket study have survived, a rate of 72.7% compared to the premarket study's 73.3%. Conversely, the survival rate among post-approval study patients who would not have been eligible for premarket study is 13.6% (or 6 of 44 patients).
FDA said the next post-approval study report is due March 20, 2020.
- FDA issued a follow-up letter Tuesday to healthcare providers emphasizing the importance of patient selection in making clinical decisions on whether to implant Abiomed’s Impella RP right heart pump system.
- The update follows FDA’s warning to physicians in February of a far higher mortality rate in post-approval study data than was seen in clinical trials supporting the device's premarket submission.
- In the new letter, FDA said the latest post-approval data showed a lower survival rate in a subgroup of sicker patients who would not have qualified for the premarket studies. The agency said the benefits of the device outweigh the risks when used in appropriately selected patients.
Abiomed’s line of Impella heart pumps treat patients with advanced heart failure by temporarily taking over pumping function to allow the heart to rest and potentially recover. FDA’s warning in February specifically pertained to the company’s system for right-sided heart failure, a less common form of the condition; typically, heart failure begins on the left side and may spread to the right side if untreated.
Impella RP, which received FDA approval in 2017 for temporary right ventricular support, represents just 5% of Abiomed’s sales. However, the FDA letter may have caused physicians to question whether the agency’s concerns extended to the whole Impella line, company officials suggested when reporting a miss in fourth quarter sales targets.
The Danvers, Massachusetts-based company issued its own statement saying the FDA update confirmed the Impella RP as safe and effective. The pump is the only right-sided device with FDA approval.
In the February communication, FDA said post-approval study (PAS) results showed only 17% of patients reached the 30-day survival target, compared to 73% who survived for at least 30 days after removal of the pump in the device’s pivotal trial.
In its update on Tuesday, FDA said interim results from the most recent Impella RP System post-approval report indicate that 12 out of the 42 enrolled patients, or 28.6%, survived to 30 days after device removal or hospital discharge, or to the start of longer-term therapy.
However, for the subgroup of PAS patients who would have met the enrollment criteria for the premarket clinical studies, the survival rate was 64.3% — “similar to the premarket study survival rate,” FDA said.
For the subgroup who would not have qualified for the premarket clinical studies, the survival rate was 10.7%, or three out of 28 patients. The primary reason for the difference in survival outcome appears to be patient selection, FDA said.
“In these patients, the PAS survival rate should be interpreted in the context of the patients' conditions and limited treatment options,” FDA said.
Based on its current analysis, FDA said, it believes the benefits of the Impella RP system continue to outweigh the risks when the device is used for the currently approved indication in appropriately selected patients.
Jefferies analyst Raj Denhoy, in a note to clients, said FDA’s latest letter should help the company begin to undo any lingering impact in the clinical community about the safety of the Impella portfolio. “Fallout from the first letter was partially blamed for ABMD's weak 4Q and resolution should restore confidence,” Denhoy wrote.