Slow Medicine: Digesting the Stomach Drain Data

Earlier this month, the FDA approved a novel weight-loss approach: using a small tube – called an "A-tube" -- to drain stomach contents after each meal.

The A-tube is placed just as a percutaneous endoscopic gastrostomy tube would be. But rather than using the tube for feeding, the A-tube is used by the patient to drain about a third of stomach contents into the toilet after each meal.

In case you're curious, here are some additional details about the device:

• Patients should allow 20-30 minutes after each meal to drain stomach contents into the toilet.
• The tube's diameter is smaller than a G-tube, so all food needs to be "thoroughly chewed" prior to swallowing.

If the A-tube (brand name "AspireAssist") were a weight-loss pill, the FDA would have required at least two large, long-term, placebo-controlled randomized trials with efficacy and safety endpoints prior to approval.

However, as a device, the barriers to entry into the market are much lower. In fact, the FDA's approval is based solely on an industry-funded feasibility study involving just 18 patients and another small industry-funded randomized trial involving 171 patients that has yet to be refereed through the peer-review process.

In the trial involving 171 patients, AspireAssist appears to have led to weight loss. According to the FDA's report, after 52 weeks there was a mean weight loss of 12.1% among patients in the A-tube group versus 3.6% among control patients.

However, there were also a substantial number of adverse events associated with the A-tube, including pain, nausea, electrolyte disturbances, and a case of peritonitis.

We also don't know whether the device can reduce rates of metabolic diseases like diabetes or hypertension as has been the case with bariatric surgical procedures (unlike the A-tube, bariatric surgery also impacts hormones and other internal regulators).

Moreover, the A-tube might create new forms of eating disorders, and we do not yet know if the benefits outweigh the downsides from the patient's perspective.

The streamlined approval process for medical devices also means that the FDA has made its regulatory decision before much of the data have been published in a peer-reviewed journal and scrutinized by the scientific community. It is possible there are important methodological shortcomings of this analysis that the FDA missed.

In fact, the industry researchers presented the findings in a misleading manner by reporting percentage "excess weight loss" rather than percentage "total weight loss" as the primary endpoint, which accentuates the magnitude of the result.

In summary, obesity impacts quality of life and drives chronic conditions that shorten and reduce the quality of our patients' lives. There is clearly a need for continued innovation to identify new strategies for promoting weight loss.

But from our Slow Medicine vantage point, removing food directly from the stomach after eating using an A-tube remains an experimental approach that is not ready for widespread use. We will await an adequately sized clinical trials designed to determine whether or not this new approach actually works, and if so, when it should be considered.

More generally, the approval of the A-tube reminds us how inadequate the FDA's process is for reviewing and approving medical devices.

"Updates in Slow Medicine" applies the latest medical research to support a thoughtful approach to clinical care. It is produced by Pieter Cohen, MD, of Harvard Medical School, and Michael Hochman, MD, of AltaMed Health System in Los Angeles. Rachael Bedard, MD, is a palliative care fellow at the Mount Sinai Hospital in New York. To learn more, visit their Facebook page.

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Slow Medicine: Digesting the Stomach Drain Data