## Facts

- Mylan Pharmaceuticals, Inc., a generic manufacturer, filed an abbreviated new drug application (ANDA) with a paragraph IV certification to market a generic version of Procter & Gamble’s Macrobid (nitrofurantoin).
- FDA approved Mylan’s ANDA, making Mylan eligible for the Hatch–Waxman 180-day exclusivity applicable to certain first paragraph IV ANDA filers.
- On the same day Mylan launched its generic, a third party licensed by Procter & Gamble began selling an “authorized generic” marketed under the brand holder’s new drug application (NDA).
- Mylan filed a citizen petition asking FDA to interpret 21 U.S.C. § 355(j)(5)(B)(iv) to prohibit sales of authorized generics during Mylan’s 180-day exclusivity period.
- FDA denied the petition.
- Mylan sued under the Administrative Procedure Act (APA), alleging FDA’s denial was arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law.
- The district court dismissed for failure to state a claim, and Mylan appealed.

## Issues

1. Whether 21 U.S.C. § 355(j)(5)(B)(iv) authorizes FDA to prohibit an NDA holder or its licensee from marketing an authorized generic during a first paragraph IV ANDA filer’s 180-day exclusivity period.
2. Whether FDA’s denial of Mylan’s citizen petition was arbitrary or capricious under the APA.

## Decision

- The Fourth Circuit affirmed the dismissal.
- The court held that § 355(j)(5)(B)(iv) does not grant FDA power to prohibit marketing of authorized generics during the 180-day exclusivity period.
- Because FDA lacked statutory authority to impose the requested restriction, FDA’s denial of the petition was not arbitrary or capricious.

## Legal Principles

- The 180-day exclusivity in 21 U.S.C. § 355(j)(5)(B)(iv) protects a qualifying first paragraph IV ANDA filer only against competition from later-filing ANDA applicants.
- Statutory text focused on ANDA applicants does not impliedly authorize FDA to regulate NDA holders’ separate ability to market, or license others to market, authorized generics.
- Under Chevron step one, where Congress has not granted the claimed authority in the statutory text, an agency may not create that authority by interpretation.
- An APA challenge fails where the agency action rests on a correct conclusion that the agency lacks power to provide the requested relief.

## Conclusion

The court held that Hatch–Waxman’s 180-day exclusivity limits subsequent ANDA approvals but does not empower FDA to block authorized generics sold under the brand holder’s NDA, and it therefore upheld FDA’s denial of Mylan’s petition and the dismissal of Mylan’s APA suit.


Mylan Pharmaceuticals, Inc. v. U.S. Food & Drug Admin., 454 F.3d 270 (4th Cir. 2006)