Testimony of Dr. Anna E. Mazzucco on Premarket Approval of Nucleus Hybrid L24 System Cochlear Implants

By Anna E. Mazzucco, Ph.D.

November 8, 2013

My name is Dr. Anna Mazzucco, and I thank you for the opportunity to speak today on behalf of the National Research Center for Women and Families.   After completing my  Ph.D. in Cell and Developmental Biology from Harvard Medical School, I conducted research at the NIH.  Those are the perspectives I bring today.

Our nonprofit organization conducts research, analyzes data in the research literature, and then explains the evidence of risks and benefits to patients and providers.  Our president is on the Board of Directors of the Alliance for a Stronger FDA, which is a nonprofit dedicated to increasing the resources that the FDA needs to do its job.  Our organization does not accept funding from medical device companies, and therefore I have no conflicts of interest.

The device under consideration here today, the Hybrid L24 cochlear implant, represents a chance for those who want to enhance their high-frequency hearing, but may have limited access to traditional cochlear implants due to their residual low-frequency hearing.  The only reason to chose this device is to enhance high-frequency hearing while preserving residual low-frequency hearing.  The critical question here today is whether or not this device fulfills that promise, and whether is does so without significant risks.

In the pivotal clinical trial, 44% of the subjects had profound or total loss of their residual low-frequency hearing.  In addition to this striking loss of residual hearing, which this device was explicitly designed to preserve, 12% of subjects exhibited worse performance in a hearing assessment 6 months after getting these implants compared to their pre-implantation baseline.

These results indicate significant failure of this device to fulfill its promise of improved hearing, while also endangering the low-frequency hearing these participants specifically wanted to preserve. 

Unfortunately, loss of residual low-frequency hearing is not the only risk.  In the pivotal study, more than two-thirds of the men and women experienced adverse events.  77% of these were surgical or medical in nature, with the remaining 23% due to the device itself.  Almost one in four of the device malfunctions involved open or short circuits of the implants.

In addition, patients who lost residual hearing and chose to have their device removed and replaced were then also vulnerable to all the risks that come with a second surgery, which are significant.  As the FDA has noted, the high rate of low-frequency hearing loss is a grave safety concern for these reasons.

A more detailed examination of this study generates even more concerns.  Although the FDA is considering approval for people age 18 and older, only one patient studied was under the age of 37!  And the total number of patients in the pivotal study was only 50, so we know even less about possible rare risks.  We agree with the FDA that this trial is underpowered, and that it cannot address safety considerations in the adolescent and young adult populations for which it seeks approval.

The company has attempted to address these concerns in several ways:

  • They proposed requiring the patient to try a traditional hearing aid prior to eligibility for this device.  But in fact, that would be difficult if not impossible to enforce.
  • They proposed post-market studies.  This is inadequate for 3 reasons:
    • It would not help the two-thirds of patients who would be expected to suffer from complications, including the 44% who would lose their low-frequency hearing immediately as a result of getting this implant, and we’d have no information about longer-term risks.
    • The proposed postmarket studies are unlikely to generate reliable information.  Following subjects for only 3 years is not adequate for a device that will be relied upon for decades of use.
    • We also agree with the FDA that this particular postmarket design is likely to be confounded by potential carry-over from the CP900 sound processor, which will have to be turned off to assess the Hybrid L24 device itself.

For these reasons, we urge you to recommend that the FDA not approve these implants at this time.  Patients deserve a real chance to benefit before undergoing surgery for a cochlear implant.

How can we make sure these implants are going to help more patients than they harm – especially compared to other options?  #1: We need larger pre-market studies that aim to reduce the risks and determine which patients are most likely to benefit and least likely to be harmed.  #2  When those studies are done, then we need studies of 18-25 year olds to make sure it is safe for them.

All of us here today want to help people with hearing loss.  BUT, medical devices should not be approved on the basis of wishful thinking, they should be approved on the basis of scientific evidence showing that the benefits are likely to outweigh the risks, compared to other options.  First, let’s do no harm.

Despite these concerns, the FDA approved the implant in March 2014: http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm389860.htm.