** Shares of drugmaker BioCryst Pharmaceuticals BCRX.O fall 4.8% to $8.60 premarket

** Co reports Q1 loss of $2.98/shr vs analysts' average profit estimate of 5 cents/shr - LSEG data

** BCRX's quarterly revenue of $156.4 million beats analysts' average expectation of $151.1 million

** Co maintains its annual Orladeyo revenue forecast to be between $625 million and $645 million

** Orladeyo is a daily pill that helps prevent swelling attacks in people with hereditary angioedema, a rare genetic condition

** Up to last close, stock was up 15.8% YTD