(Reuters) - Boehringer Ingelheim on Thursday said it will lay off some of its salesforce due to poor U.S. sales of its biosimilar version of AbbVie's blockbuster arthritis treatment Humira.

The German drugmaker said it planned to reduce its customer-facing teams in favor of a hybrid in-person and virtual sales model by June 30, in large part because pharmacy benefit managers (PBMs) had kept branded Humira on their lists of medicines for reimbursement.

That choice has led to less uptake of biosimilar versions of Humira in the United States, including Boehringer's Cyltezo, it said. The company, which has 53,000 employees worldwide, did not provide details on how many people would be laid off.

Despite nine biosimilars being launched in the U.S. last year, AbbVie has held onto more than 98% of the Humira market.

Boehringer launched Cyltezo last July but has only managed to sell 1,487 prescriptions in total since then, according to IQVIA data. Almost 2.8 million Humira prescriptions have been written during the same period.

Humira until recently was the world's top selling prescription medicine with annual sales reaching $22 billion in 2022, but has been eclipsed by Merck & Co's cancer drug Keytruda.

Unlike easy to manufacture pills that can be copied and sold as generics at a huge discount once patents lapse, complex biologic medicines made from living cells cannot be exactly duplicated and so are known as biosimilars. The introduction of biosimilars was supposed to help cut the price of expensive biotech medicines that go off patent, if not by as much as generics.

The German drugmaker priced its branded and unbranded versions the drug at a 5% and 81% discount to Humira's 2023 list price of $6,922 per month.

Swiss drugmaker Sandoz launched its biosimilar Hyrimoz with the same prices as Boehringer and Amgen, whose Amjevita was the first Humira biosimilar to hit the U.S. market, priced at a 5% and 55% discount to Humira.

Boehringer's Humira biosimilar was the first to be designated interchangeable by the U.S. Food and Drug Administration, meaning it can be substituted for the original without consulting the prescriber.

UnitedHealth Group's Optum Rx and Cigna's Express Scripts, two of the largest U.S. PBMs, chose to include Cyltezo on their insurance reimbursement lists last year alongside Humira, Hyrimoz and Amjevita.