Before this year was even halfway through it was clear that it would be a key one for biosimilars.
The biologic versions are not new to the European market, where the first entrants came in 2006 in the form of the growth hormone Omnitrope. But it's taken until 2015 for the pace to properly pick up.
This year the first biosimilar versions of tumour necrosis factor (TNF) inhibitors, a class that includes the biggest selling biologic drugs on the market at the moment, was launched in Europe.
The first such biosimilar was developed and manufactured by Celltrion and is marketed by various partners, notably Hospira under the brand name Inflectra and Mundipharma as Remsima, and provides biosimilar versions of Janssen/MSD's $10bn-a-year Remicade (infliximab).
Remicade, along with its fellow TNF inhibitors Humira and Enbrel are multi-billion dollar products, providing a potentially lucrative market for firms investing in biosimilars in this area. This is because the same complexities of development and manufacturing that prevent new entrants arriving en mass also require only reasonably modest discounts to be made compared to their originator products.
Celltrion's Remicade biosimilar is set to be joined by a biosimilar version of Amgen's anti-TNF Enbrel (etanercept) from Samsung Bioepis called Benepali, after it was last month recommended for European approval by the CHMP.
The long game
It's not been a quick route to market, but that is to be expected, says Alpna Seth, head of biosimilars at Biogen - which has partnered with Samsung on the Samsung Bioepis joint venture.
“Biogen has invested in this space for a very long time and we started to look at it as an opportunity and really quite early on,” she tells PME. “It has taken a very long time for the regulatory requirements and the environment to be clarified.”
But rather than be frustrated with the time it has taken to get to current stage, she says that the EMA has done a pretty good job of taking a lead on it.
“There's been a lot of wrestling at the intersection of science, law, regulation and business to come up with what should be the requirements for each type of product. These are complex topics and the best you can do is to have a product that is similar.”
Now Samsung Bioepis is set to bring the first subcutaneously-administered anti-TNF biosimilar to market, with Benepali endorsed for the treatment of moderate to severe rheumatoid arthritis, psoriatic arthritis, non-radiographic axial spondyloarthritis and plaque psoriasis in the EU. Next on the agenda for Samsung Bioepis are further biosimilars, with plans for Humira and Remicade biosimilars too.
“We were very attracted to Europe and these three drugs because we think this was the right time and the right portfolio to get started with,” Seth says.
The positive opinion for Samsung Bioepis' drug was swiftly followed by the news that Amgen has submitted for US FDA approval of its biosimilar version of AbbVie's Humira (adalimumab) - currently the top-selling drug in the world with sales of more than $13bn last year.
If all goes according to plan that biosimilar - known as ABP 501 - could be the first anti-TNF biosimilar with a US approval by the third quarter of 2016, unless Celltrion manages to overcome regulatory and potentially patent issues holding up its Remsima application there. Amgen will also have some intellectual property hurdles to vault, given that AbbVie maintains it has patent protection in the US until 2022.
Given that Humira, Remicade and Enbrel represent three of the top five-selling drugs worldwide - with collective sales of more than $30bn in 2014 - the entry of the biosimilars will provide a big opportunity for health systems to rein in costs.
Seth confirms this, saying: “Europe is most attractive right now from a biosimilars perspective, because there is regulatory clarity and an anti-TNF biosimilar has already been approved.
Europe is most attractive right now from a biosimilars perspective
“Then there is also some intellectual property on the major biologics expiring - so there's a great deal of interest and opportunity there from that perspective. Also, healthcare budgets are facing more pressure than ever before.”
Certainly, initial uptake for Celltrion and Hospira's Remicade biosimilars in Europe - where patents on the drug have already expired - are reported to be buoyant since they reached the market in February.
Meanwhile, away from the anti-TNF drugs, other big-hitting biologics are set for biosimilar competition.
In September a biosimilar version of Roche's big-selling cancer drug Avastin, developed by Amgen and Allergan, matched the reference drug in a phase III trial. ABP 215 was shown to be equivalent to Avastin (bevacizumab) on both the safety and efficacy measures in the trial, which involved patients with the non-squamous form of non-small cell lung cancer (NSCLC). At the moment there are no approved biosimilars of Avastin, which is currently Roche's third-biggest product with sales of CHF3.26bn ($3.33bn) in the first six months of the year.
Another product in the set to be in the biosimilar firing line is Sanofi's blockbuster insulin Lantus (insulin glargine), though that won't happen quite as quickly as was originally expected.
Lilly has agreed to hold off launching Basaglar (insulin glargine) in the US until the end of next year. Its settlement with Sanofi relates to patents covering the Lantus SoloSTAR formulation of the basal insulin, a pen injector version which accounts for almost two-thirds of Lantus $7bn total sales. It does not cover insulin glargine sold in vials or combination products.
Under the terms of the agreement Lilly has agreed to pay royalties to Sanofi in exchange for a patent license from Sanofi, and has agreed to hold off on launching its own pen-based insulin glargine product Basaglar - partnered with Boehringer Ingelheim - until December 15, 2016.
Basaglar was granted tentative approval by the FDA last year but its launch was delayed by a legal challenge for Sanofi which alleged infringement of four patents on Lantus.
Lilly and Boehringer have already started to roll-out their biosimilar in Europe under the Basaglar brand name, but delaying direct competition in the US - which accounts for two-thirds of the product's turnover - will avoid a dramatic fall-off in Lantus sales for another 12 months.
The move is especially timely, as there is ample evidence that after a slow start the US is prepared to embrace biosimilars, with a string of guidance documents emerging from the FDA this year to help drug developers file successful marketing applications.
A couple of months ago, for example, the regulator acknowledged for the first time that it is possible for a biosimilar to be interchangeable - and therefore substitutable - with a reference product.
Meanwhile, to outline the size of opportunity - or challenge if you prefer - current estimates of the global biosimilars market expected it to grow to around $25bn by the end of the decade as drugs with sales of around $100bn lose patent protection.