Hunted becomes hunter as Amgen lines up Humira biosimilar

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As one of the biggest manufacturers of biologicals, Amgen probably feels like biosimilar developers have drawn a big bullseye on its back. However, in turn it has the biggest target of all in its sights – AbbVie’s Humira.

The California-based group has reported phase III data for ABP 501 showing its copycat antibody to be the equal of Humira in treating psoriasis, which ought to raise hopes that it will be similarly effective in the biggest indication, rheumatoid arthritis. In one sense, putting a biosimilar Humira on the market might do no good for Amgen’s own RA product, Enbrel; on the other hand, ABP 501 could help the group defend itself against intensifying competition in one of the world’s most lucrative disease areas.

Amgen said ABP 501 had met a pre-specified equivalence margin against Humira on the psoriasis area and severity index in a 350-patient trial in moderate to severe plaque psoriasis. In Humira's two pivotal trials, more than 70% of patients taking the drug saw their PASI scores decrease by 75% over 16 weeks, compared with less than 20% of those taking placebo.

ABP 501 will not be submitted for regulatory review until the bigger and longer trial in RA reads out next year, so the agent will not be on the market until 2017 at the earliest. It is the lead candidate in Amgen’s biosimilar portfolio, which also features generic versions of Avastin, Herceptin, Rituxan, Remicade, and Erbitux.

The only other agent in phase III right now is the Avastin biosimilar, code-named ABP 215. Data from this head-to-head trial against Roche's solid tumour antibody are expected next year.

The bigger they are, the harder they fall

Humira makes for a huge target since it is the biggest-selling drug in the world. Sales are forecast to peak at $14.9bn in 2017 and decline to $12.3bn in 2020, according to EvaluatePharma’s consensus. This year, its RA revenue will constitute one fifth of the branded drug sales in RA, which is the second-biggest indication by sales of any in the pharma sector.

And Humira is even more attractive thanks to its composition of matter patent being due to expire in December 2016. Numerous other companies are cueing up their own projects with adalimumab as an active ingredient, including Boehringer Ingelheim, Novartis and Samsung.

As a result, there will be jostling for position when the patent expires. It is not at all clear whether Amgen’s molecule, or any of the others, will qualify as an “interchangeable” agent – one that can be substituted directly by pharmacists rather than needing to be specified by physicians.

But there is no doubt that the manufacturers of these biosimilars intend to compete on price against Humira, a $28,000-a-year treatment in the US that is on the top tier of many health plan formularies, with high levels of patient cost-sharing.

This competition is, however, likely to take chunks out of Amgen’s Enbrel. When a cheaper Humira comes to the market patients might prefer its once-fortnightly injection to Enbrel’s twice weekly. And Enbrel is only slightly cheaper than Humira at $27,000 a year.

Thus Amgen might need some hard work from its biosimilars sales force to protect its RA franchise, should ABP 501 win approval in this indication. Amgen’s future is not bound to the success of its biosimilar portfolio – this dubious honour belongs more to its cancer drug Kyprolis and cholesterol project evolocumab – but building a small revenue stream here would be useful to offset erosion of other branded biologicals.

Study Trial ID
ABP 501 in psoriasis NCT01970488

To contact the writer of this story email Jonathan Gardner in London at jonathang@epvantage.com or follow @JonEPVantage on Twitter

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