Does the donor matter? Donor vs patient effects in the outcome of a next generation microbiota-based drug trial for recurrent Clostridium difficile infection

Arnab Ray*¹, & Courtney Jones<sup>2

1</sup>Ochsner Clinic Foundation, New Orleans, LA, USA, ²Rebiotix Inc., Roseville, MN, USA

Conclusions

Based on this analysis of the PUNCH CD study, the specific donor does not affect the outcomes achieved with administration of RBX2660 for recurrent CDI. The results suggest that outcomes are patient specific and it is not necessary to switch donors in order to achieve a cure if the first dose fails, although in some cases, a second dose may be necessary. To solidify these findings, a larger study with an expanded cohort of donors whose product is again randomized to the patient is currently underway. Additional research is also needed to provide more details on patient-specific factors that could potentially impact success or failure with this therapy. Such variables could include the retention of specific antibiotics in the intestinal tract before treatment, type of antibiotic regimen used prior to treatment, additional patient comorbidities not taken into account in this study and dosage timing.

Executive Summary

• RBX2660 (microbiota suspension processed from unrelated donors) is an effective treatment for recurring CDI.
• Success of RBX2660 treatment was not significantly impacted by donor or dose order.
• Results suggest that outcomes are patient specific and it is not necessary to switch donors in order to achieve a cure if the first dose fails.

Keywords: Clostridium difficile infection, fecal microbiota transplant, fecal transplantation, FMT, FT, gut microbiota, RBX2660, stool donor