French biotechnology company DBV Technologies SA got permission to seek U.S. Food and Drug Administration approval to sell its experimental peanut-allergy patch, reassuring investors about the product’s prospects.

The FDA “agreed that the available efficacy and safety data” supports the submission of an application that, if approved, would let DBV bring its Viaskin patch to market, the Bagneux, France-based company said. The stock had its biggest gain on record.

The decision suggests that disappointing clinical trial results last year didn’t sound the death knell for DBV’s most advanced product. The stock has been on a roller-coaster lately, plunging 45 percent in one day in October when the study was reported and surging by almost as much on Wednesday.

A regulatory submission will also give DBV a head start on a key rival. Aimmune Therapeutics Inc. and Regeneron Pharmaceuticals Inc. are working together to develop a treatment for peanut allergies. Aimmune plans to release initial results from a late-stage trial of its peanut-allergy treatment this month.

DBV plans to seek permission to sell its patch for children in the second half of the year. The stock rose as much as 44 percent in Paris trading, the steepest intraday increase since the company’s 2012 initial public offering. It traded at 46.90 euros at 1:33 p.m.

Peanut allergies have become increasingly common in children. About 6 million people in the U.S. and Europe have the condition, including more than 2 million kids, according to Aimmune.

The Viaskin patch was proven to be safe and increased children’s ability to tolerate peanuts in a final-stage study, but the company said in October the results fell short of the trial’s main statistical goal. DBV stock had been a darling of investors before the disclosure.

Viaskin has breakthrough-therapy and fast-track designations from the FDA, allowing for expedited review.

The company said that it received the FDA’s written response after providing a package of clinical data to the agency. Regulators often meet with a company before the submission of a biologics license application, though in this case the FDA evinced its support without meeting.