Amgen’s employees and political action committee have distributed nearly $5 million in contributions to political candidates and committees since 2007, including $67,750 to Mr. Baucus, the Finance Committee chairman, and $59,000 to Mr. Hatch, the committee’s ranking Republican. They gave an additional $73,000 to Mr. McConnell, some of it at a fund-raising event for him that it helped sponsor in December while the debate over the fiscal legislation was under way. More than $141,000 has also gone from Amgen employees to President Obama’s campaigns.

What distinguishes the company’s efforts in Washington is the diversity and intensity of its public policy campaigns. Amgen and its foundation have directed hundreds of thousands of dollars in charitable contributions to influential groups like the Congressional Black Caucus and to lesser-known groups like the Utah Families Foundation, which was founded by Mr. Hatch and brings the senator positive coverage in his state’s news media.

Amgen has sent large donations to Glacier PAC, sponsored by Mr. Baucus in Montana, and OrrinPAC, a political action committee controlled by Mr. Hatch in Utah.

And when Mr. Hatch faced a rare primary challenge last year, a nonprofit group calling itself Freedom Path sponsored advertisements in Utah that attacked his opponent, an effort that tax records released in November show was financed in large part by the Pharmaceutical Research and Manufacturers of America, a trade group that includes Amgen.

In some cases, the company’s former employees have found important posts inside the Capitol. They include Dan Todd, one of Mr. Hatch’s top Finance Committee staff members on health and Medicare policy, who worked as a health policy analyst for Amgen’s government affairs office from 2005 to 2009. Mr. Todd, who joined Mr. Hatch’s staff in 2011, was directly involved in negotiating the dialysis components of the fiscal bill, and he met with “all the stakeholders,” Mr. Hatch’s spokeswoman said, not disputing when asked that this included Amgen lobbyists.

For years, Amgen used its clout in Washington to lobby for generous Medicare payments for its blockbuster drug, Epogen, which fends off anemia in dialysis patients.

The Medicare program covers most costs associated with treating severe renal disease, regardless of a patient’s age, and the dialysis market continues to grow steadily. In 2010, the government’s kidney program was spending $1.9 billion on injectable anti-anemia drugs like Epogen.