21 October 2022 - - The US Food and Drug Administration has accepted for review ARS Pharmaceuticals, Inc.'s (ARS Pharma) New Drug Application for neffy for the emergency treatment of allergic reactions (type I) including anaphylaxis in adults and children ≥30 kg (66 lbs). If approved by the FDA, neffy would be the first non-injectable treatment available to patients with allergic reactions (type I) including anaphylaxis, US-based Silverback Therapeutics, Inc. (NASDAQ: SBTX) said.

The FDA has assigned a Prescription Drug User Fee Act (PDUFA) target action date that is anticipated in mid-2023.

The NDA submission to the FDA was based on data from four primary registration studies supporting that a 2 mg intranasal dose of neffy met all clinical endpoints recommended by regulators and that its pharmacokinetics were within the range of approved epinephrine injection products.

These data included studies in adults, with self-administration and caregiver administration, as well as in children with Type I allergies ≥30 kg (66 lbs).

In addition, neffy has been well-tolerated to date with more than 500 individuals receiving at least one dose, and many with repeat administration.

The majority of adverse events in clinical trials were mild in nature without any meaningful nasal irritation or pain.

Type I severe allergic reactions are serious and potentially life-threatening events that can occur within minutes of exposure to an allergen and require immediate treatment with epinephrine, the only FDA-approved medication for these reactions.

While epinephrine autoinjectors have been shown to be highly effective, there are well published limitations that result in many patients and caregivers delaying or not administering treatment in an emergency situation.

These limitations include fear of the needle, lack of portability, needle-related safety concerns, lack of reliability, and complexity of the devices.

There are approximately 25 to 40m people in the United States who experience Type I severe allergic reactions.

Of those, only 3.3m currently have an active epinephrine autoinjector prescription, and of those, only half consistently carry their prescribed autoinjector.

Even if patients or caregivers carry an autoinjector, more than half either delay or do not administer the device when needed in an emergency.

ARS Pharma is dedicated to empowering at-risk patients and caregivers to better protect themselves from severe allergic reactions that could lead to anaphylaxis.

The company is developing neffy (previously referred to as ARS-1), an intranasal epinephrine product in clinical development for patients and their caregivers with Type I allergic reactions including food, medications and insect bites that could lead to life-threatening anaphylaxis.

Silverback is a biopharmaceutical company focused on leveraging its proprietary ImmunoTAC technology platform to develop systemically delivered and tissue targeted therapeutics for the treatment chronic viral infections, cancer, and other serious diseases.

Silverback's platform enables the strategic pairing of proprietary payloads that modulate key disease modifying pathways with monoclonal antibodies directed at specific disease sites. Silverback Therapeutics is located in Seattle, Washington.

On July 21, 2022, Silverback and ARS Pharma announced that the companies entered into a definitive agreement under which ARS Pharma will merge with Silverback in an all stock transaction.

Following the proposed merger the combined company will focus on the potential regulatory approval and commercialization of neffy, ARS Pharma's investigational epinephrine nasal spray for the treatment of Type I allergic reactions including anaphylaxis.

The merger is subject to customary closing conditions, including the approval by Silverback's stockholders. The merger is currently expected to close in 4Q22.