Piper Jaffray analyst Edward Tenthoff says Sarepta Therapeutics' quarterly burn remained high and unsustainable at $63.4M in Q1. At current spending levels, the company will run out of cash by the end of 2016, Tenthoff tells investors in a post-earnings research note. The analyst views this as " particularly troublesome" since he does not expected accelerated approval of eteplirsen by the May 26 FDA action date. The FDA's meeting with parents following the panel meeting "is not a presage of approval," Tenthoff writes. He reiterates an Underweight rating on Sarepta with a $6 price target. The stock is up 30c to $17.06 in morning trading.