A major obstacle in the field of biotherapeutics is the need for platform technologies that enable high
bioavailability and long-term therapeutic
exposure of biotherapies in localized
disease. Traditional approaches result in problematic trade-offs, such as
toxicity and off-target side effects. The present disclosure provides compounds comprising
follistatin domain 1 (FSD1) of
follistatin (FST), which can bind to biological structures, such as the
extracellular matrix, via
heparan sulfate without the undesired neutralizing effects on the activity of
activin A,
myostatin, and GDF11, as full-length
follistatin does. The present invention relates to fusion or conjugated proteins, compositions thereof, constructs or vectors encoding them, their medical uses, and methods for biotherapeutics.