Doesn't look good..........Ben
FDA panel rejects PLC Systems heart laser
Reuters Story - July 28, 1997 16:42
GAITHERSBURG, July 28 (Reuter) - A U.S. Food and Drug
Administration advisory committee on Monday voted 9-2 to reject
PLC System's Heart Laser System for the treatment of
chronic chest pain sufferers who do not respond to angioplasty
or coronary artery bypass surgery.
Panelists said PLC presented incomplete trial data and also
had little understanding of exactly how the heart laser
procedure, known as Transmyocardial Revascularization (TMR),
restores blood flow to damaged heart tissue.
"I suspect there is a use for this device, but the data is
woefully incomplete," said panelist Dr. Samuel Cascells of the
University of Texas Health Science Center.
Theoretically, the channel created by TMR allows
oxygen-rich blood to flow back into damaged muscle and may
cause new capillaries to grow. But panelists said PLC could not
prove any theory, leading to worries that with so many
unknowns, the procedure could end up harming patients.
If the panel understood the mechanism of action, it
"probably wouldn't have any reservations," said committee
member Dr. Henry Edmunds of the University of Pennsylvania
Medical Center.
Panelist Robert Califf of Duke University said that he was
"very troubled and concerned" about the lack of rigor and
incompleteness in PLC's one pivotal study, adding that he could
not determine safety. He also questioned whether patients
should have been allowed to "cross over" to the TMR procedure
from the control group as FDA allowed last September, saying it
muddied results. Other panelists, though, said that it might
be difficult to do a controlled trial in patients who are so
ill.
Earlier on Monday, FDA reviewers criticized PLC's data,
saying that the positive results might be due to a placebo
effect, and also that there were more deaths with TMR.
Later, panelist Cynthia Tracy of Georgetown University said
she was worried about high numbers of sudden deaths and
irregular heartbeats in TMR patients who had previous by-pass
surgery.
"It is abundantly clear that there is not a mortality
benefit to this procedure," Tracy said. PLC agreed with her
assessment.
The panel also said the company had not proved that the
restored blood flow actually reduced chest pain, or angina.
PLC said that because 65 to 75 percent of TMR patients had
reduced seriousness of angina, that the Heart Laser had
restored blood flow.
But the FDA said the firm had not provided enough imaging
studies or angina data. Only 44 percent of TMR patients had
interpretable chest scans, an FDA reviewer said.
Panelist Ronald Weintraub of Harvard University said that
13 of 101 control patients had no angina data, and asked the
company why it was missing.
"Obviously we wish we had that data now," said Xavier
Lefebvre, director of clinical affairs of PLC. He said that
patients did not return for follow-up or that study sites were
late in getting the information back to the company.
Despite what they saw as trial drawbacks, many panel
members said they thought that there might be some use for the
device in sicker patients. The FDA is not bound by its panels'
advice, but usually follows it. |
