FDA kicks back Acer's rare disease drug, demands new test—shares in freefall

FDA Building 2
An FDA rejection sent Acer Therapeutics' shares plummeting Tuesday morning. (FDA)

Acer Therapeutics’ stock plummeted more than 78% premarket this morning on news that the FDA had rejected approval of its drug Edsivo (celiprolol).

The experimental therapy, which was gunning for a license to treat vascular Ehlers-Danlos syndrome (vEDS), was slapped with a complete response letter. According to the biotech, it “will be necessary to conduct an adequate and well-controlled trial to determine whether celiprolol reduces the risk of clinical events in patients with vEDS.”

Acer used data from an analysis of a nine-year-old European study of just 53 patients for its marketing app.

The condition, the most severe form of EDS, is a life-threatening connective tissue disorder that affects all tissues, arteries and internal organs—making them extremely fragile (and thus open to rupture)—and it’s believed to affect between one in 50,000 and one in 200,000 people.

The biotech said in a statement that it “plans to request a meeting to discuss the FDA’s response” in the third quarter.

A new study will cost a pretty penny, and it also cost Acer the bulk of its worth this morning, with shares tumbling 78% in early trading on the news from more than $19 a share to less than $5.

In its very brief update, Acer CEO and founder Chris Schelling said: “We remain committed to working closely with the FDA to fully understand its response.”

The biotech is still at work on ACER-001, which is an immediate release formulation of sodium phenylbutyrate; it's being tested for urea cycle disorders and maple syrup urine disease.

Earlier this year, it also picked up osanetant, a selective, non-peptide tachykinin NK3 receptor antagonist out of Sanofi’s pipeline, which is set for trials in neuroendocrine-related disorders. (Sanofi had tried and failed to develop it for schizophrenia.)

Acer went public two years back through a reverse merger with Texas-based Opexa Therapeutics, getting a $15.7 million financing round led by TVM Capital at the same time.