ARS hits roadblock for neffy approval as FDA requests additional study

The US Food and Drug Administration (FDA) has asked for repeat-dose study results before granting approval for ARS Pharmaceuticals’s neffy (epinephrine nasal spray).

ARS plans to file a formal dispute resolution request (FDRR) to appeal the demand, which was made as part of the complete response letter (CRL) regarding its new drug application (NDA) for neffy.

Following the news, which was announced late on 19 September, ARS’s stock dropped by more than 50% in today’s pre-market trading.

Neffy is being investigated for the treatment of Type 1 allergic reactions, including anaphylaxis in adults and children who weigh ≥30 kg. Type 1 allergic reactions require immediate treatment following exposure to an allergen such as food, venom or insect stings.

Back and forth with the FDA

The requested pharmacokinetic/pharmacodynamic study would compare repeat doses of neffy to an epinephrine injection in allergen-induced allergic rhinitis conditions. This request to complete the study before approval is a reversal of a previous discussion by the FDA and ARS to conduct a repeat-dose study as part of a post-marketing plan.

In May, the FDA Pulmonary-Allergy Advisory Committee (PADAC) recommended neffy’s approval without any additional trial data. The committee voted 16:6 in favour of using neffy in adults, and 17:5 in favour of its usage in children.

ARS’s CEO Richard Lowenthal expressed his dismay, stating: “[Multiple] committee members highlighted the favourable profile of neffy in our completed single-dose nasal allergy challenge study and that any decline in exposure 20 minutes after dosing, after the expected response period, is of no concern.”

The US-based company plans to refile the NDA in H1 2024 and expects an action date to be set for H2 2024.

Neffy is currently under review for approval by the European Medicines Agency (EMA), with an option from the Committee for Medicinal Products for Human Use (CHMP) expected by the end of 2023. ARS also plans to file for regulatory approval in other countries in 2024.

The CRL issued by the FDA also requested information on nitrosamine impurities, which are potentially carcinogenic. However, ARS does not believe that the additional testing to generate the information would have any impact on the timeline for the new NDA.