Eton Pharmaceuticals files PAS to extend KHINDIVI to under-fives
Eton Pharmaceuticals has submitted a Prior Approval Supplement (PAS) to the US Food and Drug Administration requesting that the approved label for KHINDIVI (hydrocortisone) oral solution be extended to include paediatric patients younger than five years of age. The Deer Park, Illinois-based company currently holds approval for KHINDIVI in children aged five and above for replacement therapy in adrenocortical insufficiency, and the new submission is supported by bioequivalence data comparing the reformulated product to ALKINDI SPRINKLE, the FDA-approved hydrocortisone oral granule formulation.
If the supplement is accepted and approved on the agency's standard review timeline, Eton said a decision in the first half of 2027 is plausible. The company estimates there are approximately 10,000 paediatric adrenal insufficiency patients in the United States, with those under five representing what it characterises as the segment of greatest unmet need.
Strategic rationale
Sean Brynjelsen, chief executive of Eton, said the submission brings the company "one step closer to potentially expanding the label," and argued that broadening the approved age range would "drastically accelerate adoption of the product." The company positions KHINDIVI as the only FDA-approved oral solution of hydrocortisone, distinguishing it from tablet-based formulations that require manipulation and from compounded liquid suspensions that lack FDA approval. The oral solution format is designed to meet the needs of patients who cannot swallow tablets and those requiring administration via gastric tube.
The new formulation required reformulation work to address the safety constraints that originally limited the product to children aged five and above. The existing label carries a warning that inactive ingredients including polyethylene glycol 400, propylene glycol, and glycerin undergo substantial systemic absorption, which raises plasma osmolarity risk, with the concern heightened in younger children. The bioequivalence data submitted via the PAS will need to satisfy FDA reviewers that the reformulated version delivers equivalent hydrocortisone exposure to ALKINDI SPRINKLE while managing those excipient-related risks in the under-five population.
Market and competitive context
Adrenocortical insufficiency in children is a niche but commercially meaningful rare-disease segment. The FDA's orphan drug designation framework and the Rare Pediatric Disease priority review voucher programme have historically made paediatric rare endocrine conditions attractive for smaller specialty pharma companies, partly because of the voucher's tradeable value. Eton already distributes ALKINDI SPRINKLE in the United States, making KHINDIVI's potential label expansion a strategic effort to migrate younger patients onto a proprietary oral solution rather than a competitor's or a compounder's product.
The broader paediatric hydrocortisone market remains thin in terms of approved options. Compounded suspensions have historically filled the gap for infants and toddlers, but their lack of FDA oversight creates dosing variability concerns that regulators and paediatric endocrinologists have flagged repeatedly. If Eton secures the expanded indication, it would represent the only FDA-approved liquid hydrocortisone option for children of any age, a position that could meaningfully improve both patient safety and the company's commercial profile across its rare-disease portfolio.
Near-term milestones for investors include FDA acceptance of the PAS filing, any requests for additional data, and the formal approval date. Eton has not disclosed whether it anticipates a standard ten-month review or a priority review pathway for this supplement.