Avidity Biosciences ( $RNA ) Falls -34.7% After Phase III Setback (See the latest news for any ticker on Tickeron.) Avidity Biosciences (RNA) shares fell approximately 34.7% over the trailing 30 days, declining from a closing price of $13.71 on August 19, 2026, to $8.95 on September 18, 2026. The move was driven primarily by a September 8 setback for del-desiran, the lead antibody-oligonucleotide conjugate (AOC) candidate built on Avidity's platform, which missed its primary endpoint in the Phase III HARBOR study for myotonic dystrophy type 1 (DM1). $DYN $DSGN $PBYI $IDYA $NTLA