An oral protein cocktail therapeutic for C. difficile infection

Abstract

Here we show that transgenic spirulina may solve key challenges of developing effective monoclonal protein therapeutics for diseases afflicting gastrointestinal (GI) tissues. We describe, as a paradigm for this novel approach, LMN-201: an investigational four-component treatment for Clostridioides difficile (C. difficile) infection comprising four monoclonal protein therapeutics produced and delivered within spirulina biomass. Three antibody-like moieties within LMN 201 were rationally designed using a multiplicative potency framework, termed synthetic avidity, that increased in vitro toxin neutralization potency by >200-fold relative to the individual components. The fourth moiety, a lysin enzyme protein, adds direct, toxinotype-agnostic antibacterial activity. In rodent challenge models, species-relevant LMN-201-like cocktails reduced disease burden and mortality. In a human GI pharmacokinetic study, LMN-201 was present at concentrations 100- to 1,000-fold above the estimated minimally effective therapeutic threshold at the distal intestine. In Part A of a Phase 2 study, participants with C. difficile infection (CDI) were treated for seven days with LMN-201 plus standard-of-care antibiotics. The primary endpoints of safety and tolerability were assessed favorably. An interim analysis of efficacy in pre-planned coordination with the data and safety monitoring board showed an initial clinical cure rate of 21/21 (100%) and sustained clinical cure rate through four weeks of 19/21 (90.5%). These findings support LMN-201 with standard-of-care antibiotics as a viable treatment option for CDI, validate spirulina as a scalable platform for oral biologics, and establish a generalizable strategy for engineering high-potency combination protein therapeutics for diseases with a GI tissue nexus.