question: Name siRNA drugs that have entered phase 2-3 clinical trials (by 2019).
answer: siRNAs that have entered phase 2-3 clinical trials by 2019 include PF-04523655, TKM-080301, Atu027, SYL040012, SYL1001, siG12D-LODER (phase 2), QPI-1002, QPI-1007, and patisiran (phase 3).