For a disheartening example of how intense lobbying and financial contributions can distort the legislative process in Washington, consider what happened to the “fiscal cliff” bill approved three weeks ago by Congress.

Senators who play a major role in federal health care financing were happy to help Amgen, the world’s largest biotechnology company, evade Medicare cost-cutting controls by delaying price restraints on a class of drugs used by kidney dialysis patients, including Sensipar, a drug made by Amgen. That provision was inserted into the final fiscal bill by Senate aides. Many members of Congress did not know it was in the bill until just hours before it was approved.

Although other companies will benefit financially from that delay, Amgen, which has 74 lobbyists in Washington, was the only company to lobby aggressively for the provision. The delay will cost the Medicare program up to $500 million over a two-year period.

The disturbing details were revealed in a report by Eric Lipton and Kevin Sack of The Times on Sunday. The maneuvering to exempt these drugs undercuts a five-year effort to change the incentives used to pay for kidney dialysis care. Previously, Medicare had paid providers separately for the drugs and for administering dialysis treatment, a system that often encouraged overprescribing.