OAKLAND — The maker of the drug Humira will pay $24 million to settle a California lawsuit that alleged it violated an insurance fraud law, the state Department of Insurance announced Thursday.

AbbVie Inc. agreed to change the way it markets Humira but continues to deny wrongdoing, according to the settlement agreement reached on July 20.

Humira is used to treat various illnesses, including Crohn’s disease, ulcerative colitis and rheumatoid arthritis.

The 2018 whistleblower lawsuit was filed in Alameda Superior Court. It alleged that AbbVie unlawfully provided perks such as meals and drinks to California doctors to convince them to prescribe HUMIRA and used registered nurses as “ambassadors” to patients — ostensibly to provide support for patient care — without disclosing they were working for the company.

The company’s marketing practices violated the Insurance Frauds Prevention Act, leading insurers to pay more than $1 billion in improper claims, the suit alleged.

The company agreed to reforms that include having ambassadors disclose that they were paid by AbbVie rather than a health care provider. Patients also will be told about HUMIRA’s side effects.

Illinois-based AbbVie faces a similar lawsuit in that state.