Piper Jaffray analyst Danielle Brill says that while she had dismissed Solid Biosciences' (SLDB) microdystophin gene therapy program as a competitive threat to Sarepta Therapeutics (SRPT), some investors worried that Solid could provide compelling data after adjusting protocol and moving up the dose. However, today's report of another clinical hold confirms that Solid's construct is toxic, indicating that Pfizer's (PFE) may to too, Brill tells investors in a research note. The analyst points out that both Solid and Pfizer use AAV9 and have had complement mediated serious adverse events after dosing just a few patients. Solid's program reaffirms her view that Sarepta's safety profile is differentiated. It is unlikely that the competition "is viable, let alone will ever catch up," says Brill. She keeps an Overweight rating on Sarepta Therapeutics with a $185 price target. The stock in midday trading is up 4% to $99.02 while Solid Biosciences is down 71% to $3.22.