A federal court in Los Angeles dismissed a lawsuit against Amgen Inc. and two kidney dialysis providers that had alleged illegal promotion of Amgen’s anemia drugs. The court said the complaint should have been made to regulators rather than a court.

The proposed class action lawsuit involved claims by seven health benefit plans that Amgen of Thousand Oaks, DaVita Inc. of El Segundo and Fresenius Medical Care AG of Homburg, Germany, promoted the use of Epogen and Aranesp in unapproved settings, said law firm Skadden, Arps, Slate, Meagher and Flom, which represented Amgen.

Amgen and kidney dialysis centers have come under increased scrutiny by Medicare regulators over billings that included Aranesp and Epogen. The kidney dialysis process can contribute to anemia in many patients.

The U.S. District Court for the Central District of California on Friday dismissed the claims and the litigation on the grounds that it was an improper attempt to privately enforce the U.S. Food, Drug, and Cosmetics Act. News of the decision broke late Monday.

The complaint was filed under the federal racketeering statute and California’s consumer fraud laws. The court said the plaintiffs should point to specific misrepresentations made by the defendants.

“The decision in this case is very sound and rebukes the plaintiffs’ efforts to second guess the prescribing decisions of health care providers across the country,” said Mark Cheffo, a Skadden partner and lead attorney on the case.

Spokespeople for Amgen and DaVita could not be reached for comment.

Sales of Amgen anemia drugs Aranesp and Epogen, used in patients with kidney disease and cancer, have declined over the past two years after studies warned of an increased risk of death for cancer patients if high doses were used to aggressively control anemia.

Amgen shares were up $1.04, or 2 percent, to $58.17 in morning trading on the Nasdaq.