## Facts

- Amgen sought a six-month period of pediatric exclusivity for Sensipar (cinacalcet) under 21 U.S.C. § 355a.
- FDA issued a statutory “written request” specifying pediatric studies Amgen needed to conduct and submit to qualify for exclusivity.
- The written request required, for a key pediatric clinical trial, that “at least 15 subjects” complete the study.
- Amgen submitted its pediatric study results, but only four pediatric subjects had completed the relevant trial.
- FDA denied pediatric exclusivity, concluding Amgen’s submission did not “fairly respond” to the written request because it failed the minimum completed-subject requirement and did not yield meaningful conclusions.
- Amgen challenged the denial under the Administrative Procedure Act (APA), arguing the decision was arbitrary and capricious and inconsistent with FDA’s prior grant of exclusivity for Ortho Tri-Cyclen, where later review suggested many enrolled subjects did not satisfy diagnostic criteria.

## Issues

1. Whether FDA acted arbitrarily and capriciously under the APA in concluding Amgen’s pediatric studies did not “fairly respond” to FDA’s written request and in denying pediatric exclusivity.
2. Whether FDA failed to provide a reasoned explanation for treating Sensipar differently from Ortho Tri-Cyclen for pediatric exclusivity purposes.

## Decision

- The court denied Amgen’s motion for summary judgment and granted the government’s cross-motion for summary judgment.
- The court held FDA reasonably treated the “at least 15 subjects” completion term as a substantive study-design requirement, not an aspirational target.
- The court concluded FDA rationally determined that completion by only four subjects undermined the evidentiary value of the study and supported a finding that Amgen did not “fairly respond.”
- The court found FDA adequately distinguished Ortho Tri-Cyclen because the sponsor met the written request’s numeric enrollment requirement at the time of submission, and the later diagnostic concern arose from ex post reevaluation rather than failure to satisfy a core written-request term.

## Legal Principles

- Under the APA’s arbitrary-and-capricious standard, a court asks whether the agency examined relevant data and articulated a satisfactory explanation with a rational connection between facts found and the decision made.
- Pediatric exclusivity under 21 U.S.C. § 355a is discretionary; FDA may grant exclusivity only if submitted pediatric studies “fairly respond” to the agency’s written request.
- Courts give substantial deference to FDA’s scientific and methodological judgments about clinical trial adequacy and evidentiary sufficiency.
- An agency may reach different outcomes in different matters if it provides a reasoned explanation grounded in relevant factual distinctions; perfect uniformity is not required.

## Conclusion

The court upheld FDA’s denial of pediatric exclusivity for Sensipar, holding that FDA reasonably treated the written request’s minimum completed-subject requirement as essential to a “fair response” and provided an adequate explanation for any apparent difference from its earlier Ortho Tri-Cyclen decision.


Amgen Inc. v. Azar, 290 F. Supp. 3d 65 (D.D.C. 2018)