Updated from 3:56 p.m. ESTThe power of promise is immense in the biotech universe, a place where no-name companies can be made celebrities overnight, has-been stocks can rebound as must-haves and laggards can be transformed into leaders in the blink of an eye. As evidence, there's BioCryst Pharmaceuticals ( BCRX), a firm that traded north of $30 at the outset of the millennium but has gone as low as $3.68 in the last 52 weeks. However, with the help of two big developments, BioCryst has turned from a straggler to a sprinter in just a few short months. The latest news involves a deal in which the Swiss pharmaceutical giant Roche agreed to pay BioCryst $30 million for the worldwide rights to an early-stage immune system drug. BioCryst said Roche's payments could reach $530 million based on various milestones, not including possible royalty payments if the drug reaches the market. The arrangement sent shares of the Birmingham, Ala., biotech soaring 37.5% to $16.24 on more than 10 times its average trading volume. Roche bought an exclusive license to BioCryst's BCX-4208 compound, a so-called PNP-inhibitor that the companies hope will help transplant patients avoid having the new organ rejected. For five years, Roche will have a right of first negotiation on other PNP inhibitors BioCryst is already working on for autoimmune diseases or transplant rejections. BioCryst retained the right to co-promote BCX-4208 in the U.S. for several indications. Any new PNP inhibitor discovered after the agreement will be exempt. BioCryst has completed an early-stage dosing trial for the compound this year and has started a trial to evaluate the safety and tolerability of multiple oral doses of BCX-4208. The company is hoping its product proves to be more effective in treating autoimmune diseases and transplant rejections than drugs that are currently available.