Acer prepares to file for FDA approval of taste-masked formulation to challenge Horizon

Acer Therapeutics is set to file for FDA approval of a taste-masked sodium phenylbutyrate product after meeting with the agency to discuss its data. The product is designed to eliminate a cause of noncompliance with existing treatments for urea cycle disorders such as Horizon’s Buphenyl.

U.S. drug developer Acer has formulated the active ingredient in Buphenyl, sodium phenylbutyrate, into an immediate release powder. The drug, ACER-001, consists of a core center, a layer of active drug and a taste-masked coating. Acer implemented the elements to create a candidate that lacks a bitter taste and dissolves quickly in the stomach.

Acer recently held a pre-NDA meeting with the FDA to discuss a potential filing for approval of ACER-001 via the 505(b)(2) regulatory pathway. Based on the FDA’s feedback, Acer and its partner Relief Therapeutics believe they have the data to support a submission for approval.

ACER-001 came through a bridging study in 2020. The single-dose crossover study trial was designed to show the bioequivalence of ACER-001 to Buphenyl under fasted conditions. The pharmacokinetic profiles of phenylbutyrate and phenylacetate—a molecule formed in the metabolism of sodium phenylbutyrate—were similar.

Buphenyl is taken with food. By improving on the odor and taste of sodium phenylbutyrate, Acer aims to enable its formulation of the active ingredient to be taken in a fasted state. The maximum concentration of phenylbutyrate achieved by ACER-001 was higher when given in a fasted state.

If ACER-001 is approved, Acer will go to market with the support of Relief under the terms of a deal agreed in March. The deal saw Relief commit to a financial package including up to $20 million in U.S. development and commercial launch costs in return for rights to the drug in some territories and a split of the profits in other regions.