US Food and Drug Administration staffers have concluded that Sandoz' biosimilar of Amgen's blockbuster Enbrel, dubbed GP2015, is "highly similar" to its reference product, pushing the drug closer to approval.

The Novartis group is seeking clearance for five indications included in Enbrel's (etanercept) label in the US, targeting autoimmune diseases rheumatoid arthritis, psoriatic arthritis, plaque psoriasis, ankylosing spondylitis and polyarticular juvenile idiopathic arthritis.

"In considering the totality of the evidence submitted, the data submitted by [Sandoz] show that GP2015 is highly similar to US-licensed Enbrel, notwithstanding minor differences in clinically inactive components, and that there are no clinically meaningful differences between GP2015 and US-licensed Enbrel in terms of the safety, purity, and potency of the product", note documents posted to the FDA's website ahead of an advisory committee meeting this week.

However, even if the advisory committee supports the drug's approval and the FDA follows its advice, there could be a delay to GP2015's launch in the US as Amgen is suing Sandoz on grounds that its biosimilar infringes several of Enbrel's patents.

At least 11 other biosimilar versions of Enbrel are currently in the development pipeline, according to reports. European regulators have already cleared Samsung Bioepis' version, and are also currently reviewing Sandoz' drug.

Sandoz recently said GP2015 is one of five biologics it plans to launch by 2020.