Proteostasis Therapeutics, Inc., a clinical stage biopharmaceutical company developing small molecule therapeutics to treat diseases caused by dysfunctional protein processing, announced that it has successfully completed a key preclinical milestone in its collaboration with Astellas Pharma Inc. (Astellas). The milestone, which triggered an undisclosed payment from Astellas, demonstrated that selective modulation of the Unfolded Protein Response (UPR) pathway in vitro is potentially an effective disease-modifying approach in the treatment of multiple diseases with few or no therapies currently available.