Thursday, October 27, 2005

GERD Therapy Option Recalled

Traditionally, options for the treatment of gastroesophageal reflux disease (GERD) have been acid-blocking medication (for the vast majority of patients) or surgery (fundoplication, for a few patients). For the sake of brevity, I won't go over the pros and cons of each; in general, patients would prefer a non-operative treatment (which as a surgeon I just can't understand!).

GERD is a very common problem....and as a result, lots of $$ are at stake for those who can come up with a good treatment. How many ads do you see or hear about "the purple pill?" The battle between pharmaceutical companies for GERD therapy market share is intense. In the past few years, two alternative endoscopic therapies have been developed: the Stretta procedure and the Enteryx procedure. One is no longer an option.

The Stretta procedure involves application of radiofrequency energy to the gastroesophageal junction, basically causing tissue thickening in an attempt to augment lower esophageal sphincter tone, thereby decreasing the tendency of the patient to reflux. It is reasonably effective, although not the "silver bullet" many had initially hoped for (it is not, for example, efficacious in the patient with a large hiatal hernia). It has been found to be fairly safe as well.

A competing therapy aimed at creating the same process via a different method is the Enteryx procedure. The procedure consists of injection of a polymer into the lower esophageal sphincter, once again generating thickening of the tissues to augment LES function and prevent reflux. It was developed by Enteric Medical Technologies, which was later bought out by Boston Scientific. FDA approval was granted in 2003, and positive study results were reported at this year's Digestive Disease Week:

"These clinical trial results demonstrate the safety and efficacy of the ENTERYX Procedure at controlling GERD symptoms, and show that the ENTERYX Procedure contributes to high levels of patient satisfaction as compared to daily proton pump inhibitor (PPI) treatments," said Glen Lehman, M.D., Professor of Medicine and Radiology, Associate Director of Clinical Affairs, Department of Medicine, Indiana University Medical Center. "“The growing body of clinical data suggests that the ENTERYX Procedure has a place in the treatment algorithm for chronic GERD sufferers."”
That endorsement now seems a bit premature. Last week (10/14), the FDA reversed field and ordered a recall of the Enteryx kits, citing complications from injection of the polymer throught the entire wall of the esophagus, leading to (emphasis mine):
chest pain, flu-like symptoms, pneumonia, atelectasis, reactive pneumonitis, mediastinitis, pneumo-mediastinum, reactive pleuritis, pleural effusion, pericardial effusion, syncopal episodes, and flank pain. Some cases of transmural injection were not recognized at the time of the procedure or during immediate follow-up; these occurred even though fluoroscopy was used throughout the procedure. Three weeks was the longest period that we know of in which a transmural injection went unrecognized by a physician.

At this time, it is not possible to provide accurate estimates of the number of adverse events associated with transmural injection of ENTERYX®, or to describe all of the possible outcomes. Reports received thus far suggest ENTERYX® has been injected into various sites outside the esophagus including the mediastinum, pleural space and the aorta. When injected into the aorta, ENTERYX® may migrate to and occlude blood vessels which supply other organs including the kidneys. One reported death was due to injection of the ENTERYX® into the wall of the aorta, which resulted in an aorto-enteric fistula. Another patient experienced a partial reduction in renal function due to partial embolization. It is not known at this point whether ENTERYX® injected outside the esophagus can be removed.
Boston Scientific apparently initiated its recall on September 23rd, stating on their web site
The Company has been collecting and analyzing a growing body of data that indicates procedural injection technique is critical to achieving clinically acceptable results. There have been a limited number of injections through the wall of the esophagus (transmural) that were undetected at the time of the procedure and resulted in adverse events. Boston Scientific considers the possibility of an undetected transmural injection an unacceptable risk and has elected to recall these products.
I'm not a gastroenterologist, and don't know how much acceptance the Enteryx procedure had gained; none of the GI docs I routinely work with have used it (or the Stretta, for that matter). However, as a surgeon who has always had an interest in foregut surgery, I have had a natural disinclination towards these two procedures, and was concerned that transmural injection was a real, but likely rare, possiblity. It appears that it was not that rare, and that the FDA acted pretty quickly to do the right thing.