By Sasha Williams
“It was surreal,” said Dr. Robert Dowling. Dowling, an associate professor at U of L and heart surgeon at Jewish Hospital, wasn’t talking about the first time he cut open a chest, or about making medical history by assisting in the development of AbioCor, the world’s first completely implantable artificial heart. He was talking about how it felt when a panel of advisers to the federal Food and Drug Administration voted 7 to 6 this summer against permitting the sale of the AbioCor heart.
Abiomed, the company that manufactures AbioCor, sought approval for the annual sale of 4,000 artificial hearts under the Humanitarian Device Exemption. The HDE allows the sale of medical devices but requires less than the normal amount of beneficial evidence. It only requires that the device doesn’t cause harm or make patients sick. HDE devices are limited to terminally ill patients who otherwise have no known treatment options.
The AbioCor, which is made of titanium and plastic, weighs roughly two pounds and runs on internal and external lithium batteries. It is the first mechanical heart that doesn’t require a wire to stick out through the patient’s skin. With the aid of an internal motor, AbioCor is able to simulate 100,000 heartbeats a day, which allows the recipient to resume a normal level of activity.
Presently, the heart is only compatible with men who have a large frame. The answer to that problem may be AbioCor II, which Abiomed has already begun testing on animals. AbioCor II is still years away from human trials, but it will be small enough to fit most men and a large percentage of women. Also, modifications have been made to this model in order to reduce the patient’s risk of stroke, which was a concern of the FDA’s.
Fourteen men received the mechanical heart during clinical trials conducted over the past four years. Each man was terminally ill and not a candidate for a natural donor heart.
The first recipient, Robert Tools, was operated on at Jewish Hospital in Louisville on July 2, 2001. His surgeons, Drs. Dowling and Laman Gray, Jr., are co-principal investigators for the Jewish Hospital/Louisville AbioCor research team. Since 1996, both doctors have worked with Abiomed to develop the AbioCor heart.
Dowling and Gray went to Washington to speak to the FDA advisers about the benefits AbioCor offers patients who are out of options and running out of time. Accompanying the surgeons were family members of the two Kentucky recipients, Robert Tools and Tom Christerson II. Both families spoke to panel members about the effect AbioCor had on their lives.
“We got our quality of life back,” said Tools’ widow, Carol, in transcripts of the meeting provided by the FDA. Before his transplant, Tools was home-bound, tethered to an oxygen tank and unable to get around on his own. He lived almost five months after receiving the AbioCor implant. Tools’ wife stated that during those five months he was able to do things he hadn’t been able to do in years, including going out to dinner with his family and going fishing with his grandkids.
Christerson’s daughter, Patty Pryor, described the 17 months she was able to spend with her father after he received his implant in September 2001. “We had moments to sit down and make sure that there was absolutely nothing left unsaid,” she told the panel. “And sometimes we had moments to sit quietly, enjoying the presence — just enjoying the presence of one another. It doesn’t get any better.”
Ordinarily, the FDA doesn’t use a panel of advisers when considering a device under HDE. The AbioCor heart, however, is far from ordinary. It is a high-profile device followed closely by the media. According to Dowling, the FDA held the special meeting as an extra precaution.
Panelists were able to vote either for approval, approval with limitations, or not in favor. Initially, the panel voted to approve the AbioCor heart with certain limitations. But voting on the limitations proved difficult and panelists finally decided that the previous votes would be thrown out, Dowling said. Another vote was held, and the panelists voted 7 to 6 against the sale of the AbioCor heart.
After the votes were recorded, each panelist explained his or her reasoning. Reasons for turning down the AbioCor ranged from stroke risks to concerns over the small number of patients who had participated in the clinical trials.
Normally, panelists are able to review data of hundreds or even thousands of participants. In the case of AbioCor, there were only fourteen participants, each of whom were incredibly ill at the time of the surgery and later died.
“My understanding was that the panel recommended against approval because the study was incomplete. Control groups were not appropriate, and the composite end point was driven by one component that very easily could have been biased in an open study,” said John Somberg of Rush University, a panelist who voted for allowing the sale of AbioCor.
When asked about the lack of convincing data, Dowling said, “When we know more, we’ll be able to implant the heart in patients who aren’t so sick.”
The FDA is not obligated to follow the panel’s advice, and a final decision has not yet been made. Dowling and others who have worked on the AbioCor are not giving up hope that the decision could be reversed.
Liza Heapes, a communications specialist for Abiomed, said they are working closely with the FDA to get the information that the FDA needs to approve the AbioCor. However, at least for now, clinical trials are on hold.
