Shares of Sarepta Therapeutics fell nearly 26 percent Thursday as the Food and Drug Administration finalized new procedures for expanded access for unapproved drugs.
"Today, the FDA finalized its efforts to streamline the process used by physicians to request expanded access, often called 'compassionate use,' to investigational drugs and biologics for their patients," FDA Commissioner Robert Califf said in a statement.
This move could mean bad news for Sarepta's application for its Duchenne muscular dystrophy drug eteplirsen. The FDA was set to decide on the drug by May 26, but postponed the decision indefinitely.
Analysts were interpreting these rules from the FDA to mean there is a way for patients to access Sarepta's drug without approval, but that would limit any commercial upside for Sarepta and investors.
In a research note, analysts at Piper Jaffray said "this (FDA decision) could enable broader access to eteplirsen that the DMD community is desperate for, without forcing the agency to grant an approval at this time. ... Importantly, while sponsors can seek FDA authorization to charge for drugs in expanded access, it may only recoup direct manufacturing costs (not development or regulatory costs), limiting the sales potential."
In an email to CNBC, the FDA said its decision is not related to any specific drug or any other FDA actions. "The updates to the expanded access form and guidances has been in the works for a long time. ... We've been promising release of the final form for quite a while now and are pleased it is ready for physicians to use."
Jefferies analysts said they see a slight chance for Sarepta's eteplirsen to be approved. "Weak data could lead to significant consequences including perceived inconsistency and shift in future trial design. We continue to see a slim chance of approval given likely data-driven decision by the FDA under current laws."
Sapreta stock has shed almost half its value since the start of this year, as the FDA continued to postpone its meetings and decision on eteplirsen.
— CNBC's Meg Tirrell contributed to this report.