Alnylam Pharmaceuticals Inc has reported positive Phase 3 data for its RNAi therapeutic patisiran which is being developed for ATTR amyloidosis with cardiomyopathy, a disease caused by the build-up of abnormal proteins in tissues of the heart. The therapy works by silencing the transthyretin messenger RNA, thereby inhibiting the synthesis of transthyretin protein. The disease affects the heart’s ability to function properly leading to shortness of breath and an irregular heart beat.