To start the FDA approval process, the generic applicant must:

1) Certify in its ANDA that the patent in question is invalid or is not infringed by the generic product (known as “paragraph IV certification”).

2) Notify the patent holder of the submission of the ANDA.

If the patent holder files an infringement suit against the generic applicant within 45 days of the ANDA notification, FDA approval to market the generic drug is automatically postponed for 30 months, unless, before that time, the patent expires or is judged to be invalid or not infringed. This 30-month postponement allows the patent holder time to assert its patent rights in court before a generic competitor is permitted to enter.

ANDA applications containing a paragraph IV patent certification are listed on the FDA website.

The latest ANDA containing a paragraph IV patent certification was submitted to the FDA by Biovail Pharmaceuticals for eprosartan mesylate a generic version of Solvay Pharmaceuticals’ treatment for high blood pressure, Teveten.

This prospect of 180-days of exclusive marketing for new generics is a powerful incentive for generic manufacturers to pre-empt patent expiration and be first on the market.

(see also Bayer sues Teva over generic Yaz contraceptive and Teva gains approval for generic breast cancer and anti-depressant drugs)

References:

US FDA, Paragraph IV Patent Certifications

US FDA, Paragraph IV Drug Product Applications: Generic Drug Patent Challenge Notifications