Live Biotherapeutics : importance of formulation and lyophilization parametersand an example of a clinical application

Abstract

In recent years, probiotics have expanded from their traditional classification as “health promoting food” to the development of live biotherapeutic products (LBP). Traditional probiotics are marketed as food/dietary supplements while LBPs are drug products intended for treatment or prevention of diseases. This type of products offers several advantages over traditional drugs, but also entail potential challenges with development, manufacturing, and demonstration of clinical safety. To obtain a sufficient quality, LBPs are typically produced by cultivation in a bioreactor, followed by formulation and lyophilization. In the first part of the project, the impact of lyophilization parameters on physicochemical and biological properties of Limosilactobacillus reuteri R2LC was evaluated. Using sucrose as a lyoprotectant gave a better freeze-drying survival, vitality and storage stability than using trehalose. A high concentration (20%) of sucrose sometimes resulted in a collapsed structure and 15% gave the overall best properties of the lyophilized bacteria. Interestingly, vitality was positively affected by using a higher concentration (1010 cfu/ml) of bacteria. Another observation was that introducing an annealing step in the process was positive when using sucrose as lyoprotectant, but no effect was seen when using trehalose. The second part of the project describes evaluation of the genetically modified L. reuteri R2LC expressing the human chemokine CXCL12 (ILP100-Topical) in a phase 1 trial on wound healing. The product was safe and well-tolerated. In addition, it gave a larger proportion of healed wounds (76 %) on Day 32 when compared to saline/placebo (59 %) (p=0.020) and the time of wound healing was reduced by 6 days on average and by 10 days at highest dose. Also, ILP100-Topical increased the density of CXCL12+ cells in the wounds and local wound blood perfusion.