Winning the advisory committee's backing is a major step toward approval, but experts pressed Aimmune with questions on the drug's safety.

Aimmune Therapeutics (NASDAQ:AIMT) recently became the first drugmaker to warn investors about a new drug application delayed due to the ongoing shutdown. The details behind Aimmune's peanut allergy drug program and the decision by the Food and Drug Administration (FDA) not to begin a review are a little fuzzy, but one thing's clear: The FDA isn't beginning new reviews until the government reopens.