The world's first moss-produced drug candidate has the go-ahead to enter clinical trials. German regulators in September told Greenovation Biotech of Freiburg that it could begin a phase 1 clinical trial evaluating moss-aGal, a recombinant form of human alpha galactosidase, as an enzyme replacement treatment for Fabry disease. Like all plants, moss engage in post-translational modification of proteins, but unlike other plants, it does not make hyperglycosylated proteins that are immunogenic in humans. Greenovation's moss, Physcomitrella patens, produces predominantly N-mannose terminated proteins. This improves uptake by cell-surface mannose receptors throughout the body, potentially qualifying this product as a “biobetter.” Moss has several other attractive features: its genome is only 511 Mbps, and it is haploid whereas other plant systems are diploid or polyploid. In addition, moss predominantly uses a homologous recombination system for repair, which makes gene replacement efforts more efficient. Several versions of alpha galactosidase are on the market or under development: Fabrazyme (agalsidase beta) from Sanofi/Genzyme of Paris, which has been in short supply since 2009, Replagal (agalsidase alfa) from San Diego's Shire, and another plant-produced (carrot and tobacco) recombinant version of this enzyme, called PRX-102, developed by Protalix BioTherapeutics of Carmiel, Israel.
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First moss-made drug. Nat Biotechnol 33, 1122 (2015). https://doi.org/10.1038/nbt1115-1122a