Adamis Pharmaceuticals said on Monday the U.S. Food and Drug Administration rejected its emergency treatment for acute anaphylaxis, a severe allergic reaction, for the second time.
The San Diego-based drug developer’s stock lost more than half its value in premarket trading.
The company said it received the FDA’s “complete response letter” late Friday for the epinephrine injection, a pre-filled single-dose treatment.
The regulator has asked Adamis to expand two studies on the product to support its approval.
The company said it expects to complete the additional testing and submit the data to the FDA by the second half of 2016.
The FDA had rejected the original marketing application for the treatment in March 2015 on concerns related to the volume of dose delivered by the syringe.
Anaphylaxis is a serious, sometimes fatal, allergic reaction, which can occur rapidly due to exposure to an allergen including food, insect stings, medications or latex.