Merck ($MRK) is offering about £48 million pounds ($74 million) in rebates and discounts to the U.K.'s National Health Service on £191 million sales of Remicade, Colin Wheeler, Merck's medical affairs director toldBloomberg. He said that compared with discounts of between 25% and 30% being offered by Napp Pharmaceuticals and Hospira, now part of Pfizer ($PFE), on the biosimilars of Remicade they offer. He said biosimilars currently hold only 5% of the market in the U.K.

The move comes after England's cost-effectiveness watchdog, the National Institute for Health and Care Excellence (NICE), gave biosimilars an edge in the country with new guidance that incorporated the biosimilars and stipulates that the least expensive drug be used ahead of more costly options.

Merck reported that its sales of Remicade, which it licenses from Johnson & Johnson ($JNJ), were off about 25% in the second quarter. It attributed that revenue hit to heavy discounting of a biosimilar developed jointly by Hospira and South Korea's Celltrion but marketed separately by them as Inflectra and Remsima.

Merck execs have said discounts of the biosimilars have averaged about 45% to the price of Remicade. But reports out of Norway said that discounts reached nearly 70% from Finnish drug company Orion Oyj when it got into a pricing war with Hospira over public tender contracts there. Steinar Madsen, medical director at the Norwegian Medicines Agency, told Bloomberg at the time that doctors felt the price difference was too great to ignore and had been switching their patients from Remicade to the lower-cost biosimilars.

Several months later, Hospira reportedly won a large contract from France's Assistance Publique, Hôpitaux de Paris by offering what looked to be a 45% discount to the popular Remicade. The facility services about a fourth of the country's population.

The big question will be how quickly and how well biosimilars are adopted in the U.S., where they have no track record. Celltrion has submitted the duo's biosimilar for FDA review the big question is how it will be received in the U.S. where biosimilars are only now making a debut. Last month, Novartis ($NVS), through itsSandoz generics business, launched the first ever biosimilar in the U.S., its version of Amgen's ($AMGN) blockbuster Neupogen, marketed as Zarxio. Earlier this month it went to the FDA with an application for a homemade version of etanercept, an autoimmune treatment that brought in more than $4.5 billion for Amgen last year.