 Heres a roundup of top developments in the biotech space over the last 24 hours.Scaling The Peaks Biotech Stocks Hitting 52-week Highs April 21 Alnylam Pharmaceuticals, Inc. NASDAQ: ALNY Arcturus Therapeutics Ltd NASDAQ: ARCT Arvinas Inc NASDAQ: ARVN Exelixis, Inc. NASDAQ: EXEL 