Doxycycline has been shown to disrupt transthyretin amyloid (ATTR) fibrils [1] and tauro-ursodeoxycholic acid (TUDCA) has been shown to reduce TTR toxic aggregates in mice [2]. Further, in 2010 Cardoso et al. showed that a combined doxycycline/TUDCA treatment had a synergistic effect, decreasing ATTR deposition. Ursodeoxycholic acid (UDCA) is a bile acid used for the treatment of certain cholestatic syndromes with an efficacy similar to that of TUDCA. Based on this knowledge, we wanted to explore if treatment with doxycycline and UDCA (Dox/Urso) would prevent disease progression in ATTR amyloidosis. UDCA was selected since TUDCA is not available in Sweden.