By SUDHIN THANAWALA, Associated Press

SAN FRANCISCO (AP) — Pharmaceutical giant AbbVie illegally plied doctors with cash, gifts and services to prescribe one of the world's best-selling drugs, Humira, despite its potentially deadly complications, a California official said in a lawsuit filed Tuesday.

The lawsuit by the state's insurance commissioner accuses the company of a far-reaching kickback scheme that led doctors to write more prescriptions for the drug, tainting their relationship with patients and driving up insurance costs.

Humira is an injectable drug that is widely advertised as a treatment for rheumatoid arthritis and other inflammatory conditions and comes with a warning for cancer and serious infections that can turn deadly. It had sales of over $12 billion in 2017, according to the lawsuit.

California Insurance Commissioner Dave Jones said insurance companies paid more than $1.2 billion for Humira for California patients between 2013 and August 2018. That figure makes the lawsuit the largest health care fraud case in the state insurance department's history, according to Jones' office.

AbbVie, which is facing billions of dollars in penalties, said the allegations are "without merit."

"AbbVie operates in compliance with the many state and federal laws that govern interactions with health care providers and patients," the company's statement said.

The kickback scheme "resulted in patients being directed to use the drug, being denied information that they would otherwise need to rely on to make determinations about whether it was appropriate for them to use the drug and significant additional insurance payments for the drug," Jones said in a telephone interview.

AbbVie paid for doctors' meals, drinks and travel to get them to write more prescriptions for Humira, according to the lawsuit. The kickback scheme also included nurses whom the company sent to the homes of patients taking the drug, the lawsuit says.

The nurses saved doctors money by handling paperwork and other tasks that normally fall to physicians' offices. They also downplayed Humira's risks when patients raised concerns, the lawsuit says.

"If given the choice between two medications, one which comes with free nurses and administrative staff and another that requires the provider to pay professional salaries, the provider cannot but help factor the substantial nursing kickback into their prescribing calculus," the lawsuit says.

AbbVie said nursing help and other support services that it provides educate and assist patients with their therapy and "in no way replace or interfere with interactions between patients and their health care providers."

The state's lawsuit is based on allegations by a registered nurse who worked for AbbVie. The nurse is also a party to the suit.