Botulinum A toxin injected into the gastric wall for the treatment of class III obesity: a pilot study

Obesity represents a major public health problem in western countries. Initial studies suggest that injection of botulinum A toxin (Btx-A) into the antropyloric region inhibits propulsive contractions of the antral pump, with delay in gastric emptying, early satiety and weight loss.

After approval by the University Ethics Committee, we prospectively evaluated 12 patients with class III obesity divided into 4 groups of 3 patients each. In groups I and II, 200 U Btx-A were injected into the antropyloric region at 8 and 16 sites, respectively. Groups III and IV received 300 U Btx-A into the antropyloric region at 16 and 24 sites, respectively. Body weight and gastric emptying time (GET) of solids and semi-solids using 13C-octanoic acid breath test and 13C-acetic acid breath test, respectively, were determined before and after injection over a period of 12 weeks.

Pre- and post-treatment body weight or solid and semi-solid GET did not differ significantly between groups (P>0.05). All patients reported a feeling of early satiety. No adverse effects related to BtxA or complications resulting from the endoscopic procedure were observed.

The injection of different doses of BtxA at different sites in the antropyloric region of patients with class III obesity did not interfere significantly with the solid and semi-solid GET or body weight of these individuals. However, early satiety was reported by all patients, the procedure was safe and no side-effects of the treatment were observed. Further controlled studies involving different methodologies regarding dosage of Btx-A and sites of injection are necessary.