The FDA updated its warning on liquid-filled intragastric balloons used to treat obesity after receiving five new reports of patient deaths.

Four of the patients were implanted with Apollo Endosurgery’s Orbera balloon, while the fifth was implanted with ReShape Medical’s Integrated Dual Balloon System. Intragastric balloons are designed to treat obesity by taking up room in the stomach, making patients feel full.

In three of the reports, the patients died within three days of device placement, while in the other two, the patients died within one month of the procedure, the FDA said.

"At this time, we do not know the root cause or incidence rate of patient death, nor have we been able to definitively attribute the deaths to the devices or the insertion procedures for these devices," the agency said.

"Patient safety is a key priority in everything we do at Apollo Endosurgery and we take adverse event reporting obligations related to our products very seriously," said Apollo Endosurgery CEO Todd Newton in a statement. "The FDA letter is an important reminder to the physician community that obesity is a serious disease and many obese patients are affected by one or more co-morbid conditions due to their obesity. In our physician training, we are diligent to emphasize the factors that support the safe and effective use of Orbera and we will continue to do so."

The FDA update comes six months after the agency issued a letter recommending that healthcare providers keep an eye out for two types of adverse events in patients who have been implanted with Apollo and ReShape’s devices. These are spontaneous overinflation, with liquid or gas, of the devices and acute pancreatitis. Both complications require the removal of the device. Since the February letter, both ReShape and Apollo have changed their devices’ labeling to address these risks.