Swiss drugs maker Serono has admitted it was guilty of illegally promoting its Aids drug, Serostim, and has agreed to pay a $704m (£398m) settlement.
Serono was alleged to have offered kickbacks to doctors
The payout relates to allegations that it offered kickbacks to doctors to write prescriptions for the drug to boost sagging sales.
The settlement was agreed with the US Justice Department.
Serostim is a US approved growth hormone used to treat muscle wasting in Aids patients.
Serostim was backed by the Food and Drug Administration (FDA) regulators in 1996 at about the same time the FDA approved protease inhibitor drugs.
Out of date
Protease inhibitors revolutionised treatment for HIV and Aids and made patients less prone to muscle wasting, and therefore less in need of drugs such as Serostim.
Four former Serono executives were indicted in April on charges of offering illegal payments to doctors for prescribing the drug. The company made more than $90m profit during the period of illegal promotion, the Justice Department said.
"Serono abused the system of testing and approval, and put its desire to sell more drugs above the interest of patients," said US Attorney General Alberto Gonzales.
Serono Labs will be excluded from all federal health care programs for at least five years.
The Serono settlement is the latest in a series of 'whistleblower' claims that have cost major drug firms more than $3bn in recent years.
Last month, UK giant GlaxoSmithKline announced it would payout $150m to settle allegations that it overcharged the US government for two anti-nausea drugs.
Meanwhile, US federal and state officials are said to be probing 150 price and marketing fraud cases involving more than 500 drugs.