(Reuters) - A federal judge ordered a Johnson & Johnson unit on Friday to pay the U.S. government $1.64 billion after a jury found it liable in a whistleblower lawsuit for illegally promoting the HIV drugs Prezista and Intelence.

U.S. District Judge Zahid Quraishi in Trenton, New Jersey, ordered the drugmaker's Janssen unit to pay $360 million for violating the federal False Claims Act.

He also imposed $1.28 billion in civil fines, or $8,000 for each of 159,574 false claims the jury found were submitted to programs such as Medicare, Medicaid and the AIDS Drug Assistance Program.

Quraishi set aside the jury's $30 million award for violations of various state false claims laws, citing a lack of evidence. The June 13, 2024 verdict followed a six-week trial.

Janssen had sought a new trial, saying the verdict was tainted by a lack of proof and by erroneous jury instructions.

Johnson & Johnson, based in New Brunswick, New Jersey, said it is confident the verdict will be reversed on appeal.

The plaintiffs Jessica Penelow and Christine Brancaccio, who worked as Janssen sales representatives, accused Janssen of improperly marketing Prezista and Intelence for off-label uses.

This included promoting Prezista as "lipid-neutral," meaning it would not affect cholesterol or triglyceride levels, contrary to its U.S. Food and Drug Administration-approved label.The plaintiffs also said Janssen paid doctors to promote the drugs at dinner and speaker programs, with the payments amounting to kickbacks.

Jurors found Janssen liable for some off-label claims, and no liability for the kickback claims.

In a 35-page decision, Quraishi said there was sufficient evidence that Janssen's off-label marketing was a "substantial factor in causing physicians to submit claims for reimbursement to government payors, and that it was reasonably foreseeable that false claims would result from such conduct."

Johnson & Johnson disputed that conclusion.

"Janssen's promotion of its life-saving medications always was consistent with the FDA-approved labels, and plaintiffs failed to present any evidence that Janssen's promotion was false, material to or the cause of the government," it said.

The $360 million portion of the award is three times the $120 million the jury awarded under the federal False Claims Act, which allows triple damages.

False claims statutes let whistleblowers sue on behalf of governments, and share in recoveries.

Pete Marketos, a lawyer for Penelow and Brancaccio, said he was grateful the judge took Janssen's "years of egregious conduct" into account in assessing an appropriate penalty.

The case is U.S. ex rel Penelow et al v Janssen Products LP, U.S. District Court, District of New Jersey, No. 12-07758.

(Reporting by Jonathan Stempel in New York; Editing by Richard Chang)