Amgen has suffered a setback in seeking pediatric exclusivity for its blockbuster drug, Sensipar (cinacalcet hydrochloride), a calcium-reducer, as it faces generic-drug competition. A federal district court has ruled in favor of the US Food and Drug Administration (FDA), which had denied Amgen’s request for pediatric exclusivity, which would have provided the drug with six additional months of market exclusivity.

Sensipar/Mimpara (Mimpara is the proprietary name of the product outside the US) had 2017 global sales of $1.71 billion, with the US accounting for the lion’s share of those sales at $1.37 billion, and the drug faces generic-drug competition. A composition of matter patent in the US expires in March 2018. Amgen is engaged in litigation with a number of companies seeking to market generic versions of Sensipar surrounding its formulation patent that expires in September 2026, according to Amgen’s 2017 annual filing. The FDA granted tentative approval for Sensipar generics to several companies, including Teva Pharmaceutical Industries, Mylan, and Aurobindo Pharma, a Hyderabad, India-headquartered generics and active pharmaceutical ingredients manufacturer.

This most recent ruling is the second time that Amgen had lost a dispute with the FDA over pediatric exclusivity for Sensipar. In the earlier opinion and order from the US District Court for the District of Columbia in January 2018, the court granted the FDA summary judgment on all but one of Amgen’s claims, namely, whether the FDA’s denial of pediatric exclusivity for Sensipar was consistent with the agency’s granting pediatric exclusivity for Johnson & Johnson’s drug Ortho Tri-Cyclen (ethinyl estradiol and norgestimate), an oral contraceptive, and if not, whether there was a reasoned explanation for the disparate outcomes. In its subsequent February 2018 ruling, the court ruled in favor of the FDA regarding Ortho Tri-Cyclen. “The court, accordingly, is now satisfied that the FDA has offered a reasoned—and reasonable—basis for distinguishing the Ortho Tri-Cyclen precedent,” the ruling said.

Amgen had filed its lawsuit against the FDA in the federal district court in May 2017 for denying pediatric exclusivity for Sensipar on several grounds, including that the FDA’s denial of pediatric exclusivity for Sensipar was “arbitrary and capricious.”  Amgen contended that the FDA’s decisions granting pediatric exclusivity for Bristol Myers-Squibb’s Orencia (abatacept), an autoimmune drug, and Johnson & Johnson’s Ortho Tri-Cyclen, were inconsistent with its denial for Sensipar, and that the agency failed to “provide a legitimate reason” for treating Sensipar differently. The FDA said that it denied pediatric exclusivity for Sensipar because it could not draw “any conclusions about the safety” of the drug in a key age group because of “Amgen’s failure to provide sufficient safety data.” In January 2018, the federal district court granted in part and denied in part the summary judgment and remanded the case to the FDA for the limited purpose of the FDA addressing whether the FDA’s denial of pediatric exclusivity in the case was inconsistent with a prior FDA pediatric-exclusivity decision on Johnson & Johnson’s Ortho Tri-Cyclen. The FDA responded that its denial of pediatric exclusivity for cinacalcet hydrochloride was appropriate and not inconsistent with its prior decision. The federal district court ruling in February 2018 ruled in favor of the FDA.  

In August 2017, the European Commission granted marketing authorization of a pediatric formulation (granules in capsule for opening) of Mimpara for treating secondary hyperparathyroidism (sHPT) in children aged three years and older with end-stage renal disease on maintenance dialysis therapy in whom sHPT is not adequately controlled with standard of care therapy.

Source: United States District Court For the District of Columbia