Horizon Pharma plc, a leading biopharmaceutical company, announced that it received a Notice of Allowance from the United States Patent and Trademark Office (USPTO) for US patent application number 14/596,919 (US publication number 2015-0126607), entitled "Diclofenac Topical Formulation" that covers the company's US approved product Pennsaid (diclofenac sodium topical solution) 2 per cent w/w (Pennsaid 2 per cent), an osteoarthritis pain drug.

This Notice of Allowance concludes the substantive examination of the patent application and will result in the issuance of a US patent after administrative processes are completed. The US patent scheduled to issue from this application will expire in 2027. After issuance, Horizon plans to list the patent in the FDA's Approved Drug Products with Therapeutic Equivalence Evaluations, or Orange Book. This will be the tenth US patent to be listed in the Orange Book for Pennsaid 2 per cent.

Pennsaid 2 per cent w/w is a non-steroidal anti-inflammatory drug (NSAID) indicated for the treatment of pain of osteoarthritis (OA) of the knee(s). Pennsaid 2 per cent contains diclofenac sodium, an NSAID, and also includes dimethyl sulfoxide (DMSO), a powerful penetrating agent that helps ensure that diclofenac sodium is absorbed through the skin to the site of inflammation and pain. Pennsaid 2 per cent is an alternative to oral NSAID treatment, reducing systemic exposure to a fraction of that provided by the oral NSAID diclofenac. The only topical NSAID offered with the convenience of a metered-dose pump, Pennsaid 2  per cent is applied in two pumps, twice daily, to the site of OA knee pain.

The most common adverse events in a phase 2 clinical trial of Pennsaid 2 per cent were application site reactions, such as dryness (22 per cent), peeling (7 per cent), redness (4 per cent), itching (2 per cent), pain (2 per cent), skin hardening (2 per cent), rash (2 per cent) and scabbing ( < 1 per cent). Other adverse reactions occurring in > 1 per cent of patients receiving Pennsaid 2 per cent included bladder infection (3 per cent), bruising (2 per cent), sinus congestion (2 per cent) and nausea (2 per cent).