Jan 3 (Reuters) - CVS Health said on Wednesday it will remove AbbVie’s blockbuster rheumatoid arthritis drug Humira from some of its lists of preferred drugs for reimbursement as of April 1, and will recommend biosimilar versions of the medicine instead.

CVS said Hyrimoz and an unbranded version of Humira, both from Swiss drugmaker Sandoz, will be covered across all its formularies, while branded and unbranded near copies of the drug from India's Biocon will be covered on some reimbursement lists.

CVS also announced that AbbVie and CVS-owned company Cordavis, which launched in August, will produce a co-branded version of Humira that will be made available to customers in the second half of this year. While most biosimilars are near copies of the branded drug, the Cordavis version will be identical to Humira in its formulation, CVS said.

Unlike generic versions of easy to produce pills that are exact duplicates of the branded medicines, complex biotech drugs made from living cells cannot be exactly matched, thus the term biosimilar.

“By preferring biosimilars that have a significantly lower list price than their reference product, CVS Caremark is putting our customers in the driver’s seat to best meet the healthcare needs of their members and lower drug costs,” said David Joyner, president of CVS's Caremark pharmacy benefit division.

Pharmacy benefit managers (PBMs) act as middlemen for employers and health plans. They negotiate rebates and fees with manufacturers, and create lists, or formularies, of medications that are covered by insurance, and reimburse pharmacies for patients' prescriptions.

A CVS spokesperson said the company expects most of its customers to transition their coverage to biosimilars of Humira, known chemically as adalimumab, once the original drug is taken off formulary, although they will still have the option to cover Humira under some plans.

Humira was once the world's biggest selling prescription medicine with peak sales of $21.2 billion in 2022.

AbbVie said it had expected some payers to make formulary adjustments as more biosimilars entered the U.S. market, and that Humira remains widely available for patients alongside other adalimumab treatment options.

CVS had chosen to keep Humira on the reimbursement list it updated for Jan. 1 2024.

Although nine Humira biosimilars were launched the U.S. last year from drugmakers including Amgen, Pfizer and Boehringer Ingelheim, AbbVie has managed to retain most of the market by negotiating favorable positions on insurance drug coverage lists.

According to data from IQVIA, an average of nearly 76,000 Humira prescriptions were written per week in the second half of last year. Closest competitor Amgen averaged 417 prescriptions per week for its biosimilar Amjevita.

In July, AbbVie said it expected Humira sales to fall by two percentage points less than it had forecast at the start of the year because of those favorable insurance positions.

Three PBMs - Caremark, Cigna's Express Scripts and UnitedHealth Group's Optum Rx - control 80% of the U.S. prescription drug market. (Reporting by Patrick Wingrove Editing by Bill Berkrot)