A randomized open label pilot study evaluating the efficacy of two dosing regimens of rifamycin SV MMX in the treatment of small intestinal bacterial overgrowth

Abstract

Antibiotics have demonstrated efficacy in the eradication of the underlying overgrowth bacteria and improvement of symptoms of small intestinal bacterial overgrowth (SIBO). The use of standard antibiotics may cause intolerable side effects such as development of multidrug-resistant enteric bacteria, Clostridioides difficile infections and dysbiosis. Nonabsorbable antibiotics have the advantage of minimized side effects. Rifaximin, an antibiotic of the ansamycin class has been shown to be effective in the treatment of SIBO. We evaluated the use of another ansamycin antibiotic, rifamycin SV MMX (AEMCOLO) in the treatment of SIBO. One difference from rifaximin is the site of delivery of AEMCOLO which appears to be the distal small intestine and colon. Hence by maintaining the microbial milieu of the proximal small intestine, the clearance of the overgrowth bacteria might be enhanced. The side effect profile of Rifamycin SV MMX has been described elsewhere in the pivotal trials; there were no safety signals noted in this study. This randomized open label pilot study evaluated the efficacy of two dosing regimens of AEMCOLO in treating SIBO. We used a simple randomization method to assign participants into study groups. The participants included 31 patients, split between two treatment arms: one receiving the medication twice daily and the other - three times daily. The outcomes were assessed based on symptom improvement and breath test normalization. The results indicated a beneficial response with both dosing regimens leading to symptom improvement and breath test normalization. Further evaluation revealed that in the three-time daily regimen, greater symptomatic improvement was observed. For clinicians treating SIBO, this study suggests that AEMCOLO is a viable treatment option. A double-blind, placebo-controlled design will probably be necessary to ascertain the true efficacy of different dosing regimens of AEMCOLO in treating SIBO.

Trial registration: ClinicalTrials.gov NCT04501380.

Fig. 1

Pre-Post Treatment Comparison of Symptoms. Visual Analog Scale (VAS) score for Arm A vs. Arm B. VAS 1 (Pre) and VAS 3 (Post 1 month treatment). Scores were added for an overall score out of a possible 60 points. Based on those in Arm B there was a 66.7% improvement in overall symptoms vs. a 25% improvement in Arm A showing a 41.7% difference of improvement between Arm B vs. Arm A

Fig. 2

Proportions of Outcomes in SIBO Treatment Study. Both treatment arms (Arms A &B) experienced symptomatic improvement of 45.2%. Both arms also experienced breath test normalizations (Greater than 50% improvement in Hydrogen, Methane, or both) of 58.1%. Arm A (twice daily dosing), 25% of participants experienced both symptomatic improvement and normalization of the breath test. In treatment arm B (three times daily dosing), 53.3% of participants experienced both symptomatic improvement and normalization of the breath test. These results suggest three times daily dosing regimen (Arm B) was associated with a 28% increase in participants experiencing both symptomatic improvement and breath test normalization compared to the twice daily dosing regimen