You are walking a slippery slope. I think we've all been here: nothing is worse than not being on the rocket when it leaves for the moon. With this security, the trajectory is undoubtedly up and news and gains can come at any time. Play that game at your own risk.
If you know what you're buying/holding in biotechland, you don't set stop losses because one day you'll come home to find yourself with fewer shares and news released that sends "your" shares way up! Tsk tsk!!
Expect TSRX to give back 50% of its net gain to profit taking/consolidation whenever it makes a run up as it just did. By setting a trailing stop loss, you will likely be selling at a price you should otherwise by looking for as an entry point.
why a 50% retracement? TSRX has just recently gained widespread market attention. Too many are interested in a "good" buy in. This will continue it's climb untill the teens till it settles or merges or partners or gets PDFUA.
It won't drop that much -though it's insurance against an overall hard mkt. selloff on profit taking. With TSRX's run up in the past few months & esp. the past couple wks. along w/ the rest of the indices well..... Hey, the mkt's trying to set a new record for the # of up days not seen since 2004. If it achieves that then what?