(W0930-01-05) Oral Targeting of Sensitive Microbiome: A Case from Development of Functional Coated Capsule to Clinical Trial Phase 1b

Purpose: Growing scientific evidence strongly suggests that micro­biome plays a crucial role in various diseases, impacting every­thing from immune function and inflammation to metabolism and mental health. Understanding these implications could lead to groundbreaking advancements in disease prevention, diagno­sis, and treatment. Cancer and its treatments can disrupt the gut microbiota, impair gut epithelial repair mechanisms, and compromise immune homeostasis and responsiveness. Microbiome therapy can prevent the decay of the gut ecosystem, preserve immune homeostasis, and optimize gut function. Formulating live biotherapeutics and accelerating drug development time can be challenging and in order to achieve the desired clinical outcome, a robust and targeted delivery system is crucial. Microorganisms are normally sensitive to acidic conditions and therefore require an acid-resistant delivery system. At the same time, they should not be exposed to the high moisture and temperatures of standard enteric coating processes, which could lead to a reduction in the number of viable microorganisms. The use of a customized, empty, ready-to-fill, modified-release coated capsule is a viable alternative for this type of therapy. The objective of this study was to develop a suitable oral delivery system for the full ecosystem fecal microbiota and test its safety and tolerability in acute myeloid leukemia (AML) patients exposed to intensive rounds of chemotherapy and antibiotics in a Phase 1b clinical trial.

Methods: Pre-locked, hard HPMC capsules were used for this study. Empty capsules were coated with a proprietary combination of EUDRAGIT^® polymers to a specific weight gain based on their surface area. These ready-to-fill enteric capsules, called EUDRACAP^® Select, were compatible with standard filling equipment and required no banding or additional downstream processing. Coating performance was evaluated via a three-stage dissolution test. Caffeine:lactose blends were filled into enteric-coated size 0 capsules. Dissolution tests were performed in USP Type II apparatus at 37°C, with a basket speed of 75 rpm; filled capsules were exposed to 0.1 N HCl media for 2 hours followed by pH 6.8 potassium phosphate monobasic buffer for 1 hour and pH 7.2 buffer for 2 hours. The developed capsules were also subjected to a biorelevant dissolution test. For that, the dosage form was subjected to sequences of agitation, including movement and pressure fluctuations, alternating with static phases, as observed in vivo. The intermittent contact of the dosage form with the dissolution medium and the intestinal pH profiles, characteristic of fasting intake conditions, were also simulated with a biorelevant medium. For the Phase 1b clinical study, the capsules developed were filled with a specific amount of MaaT’s proprietary standardized, high-richness, high-diverse microbiome ecosystem, containing a group of bacterial species known to produce anti-inflammatory short-chain-fatty acids. The study was performed according to the approved protocol (identifier of the study: NCT04150393).

Results: Figure 1 shows dissolution profiles of the 3 developed prototypes. Prototype 2 showed full protection in HCl 0.1 M up to 120 min and also for a further 60 minutes in pH 6.8, after which its contents were rapidly released in pH 7.2. Therefore, Prototype 2 was selected as the most promising formulation. It has also shown to be stable for over 6 months in the different tested conditions: long-term, accelerated, and long-term refrigerated (data not shown). Results of the stress test are detailed in Figure 2, which shows there is no release of capsule contents for up to 2 hours. During simulated gastric emptying and other waves of pressure, the capsules yielded no deformation and signs of leakage. The mechanical agitation simulated at 3 hours triggered fast dissolution of part of the tested capsules. Ileocecal passage at 4 hours triggered fast drug release (deformation and perforation) from the capsules. The results of the Phase 1b clinical trial shows that strong and sustained engraftment was observed in all four cohorts². The engraftment level refers to the ratio of operational taxonomic units (OTU) that were not present in the patient at baseline, but were present in the administered microbiome and were found in the patient following treatment. For this analysis, shared OTUs between formulated microbiome and patients at baseline were excluded. Persistent engraftment can be observed by relatively stable OTU levels at V4, following consolidation of chemotherapy and about 4 weeks after the treatment was finished. Similar to the engraftment results, an increase in the number of OTUs was induced, which was also persistent, showing improved richness. These results are shown in Figure 3.

Conclusion: In vitro testing has demonstrated the efficacy of the developed EUDRACAP^® Select used in the investigated formulation, even under stressful conditions. Microbiome filled capsules appear to be safe and effective in restoring gut microbiota in the referred clinical study protocol. Three capsules per day for 1 week induce an increase in microbiota richness and an effective and persistent engraftment.

References: 1. G. Garbacz, S. Klein, Dissolution testing of oral modified-release dosage forms, J Pharm Pharmacol, 64 (2012) 944-968. Peled, J.U. et al. Microbiota as Predictor of Mortality in Alloceneic Hematopoietic-Cell Transplantation. N Engl J Med 382, 822-34 (2020). doi: 10.1056/NEJMoa1900623.
2. Ghani R et al, Disease Prevention Not Decolonization: A Model for Fecal Microbiota Transplantation in Patients Colonized With Multidrug-resistant Organisms. Clin Infect Dis. 2021 Apr 26;72(8):1444-1447 doi: 10.1093/cid/ciaa948.


Dissolution profile of prototypes of enteric coated ready-to-fill capsules


Biorelevant test


Clinical trial Phase 1b results