The FDA’s first-ever biosimilar approval on Friday is a watershed moment for the healthcare system, with pharma companies seeking to capitalize on the new opportunity in the US biologics market, which garnered $1 billion in sales in 2013.

Amgen’s Neupogen (filgrastim) will be the test case for the US’s biosimilars market now that the FDA approved Sandoz’s lookalike version of the branded biologic, almost two months after a unanimous FDA panel endorsement.

The FDA granted Sandoz’s version of the drug, which is known as Zarxio (filgrastim-sndz), the same indications as Amgen’s Neupogen, which means the two companies will compete for the same patients, a pool that includes severe chronic neutropenia, bone marrow transplant and cancer patients. Sandoz is owned by Novartis.

The approval does have limits. The FDA only approved the drug as a biosimilar as opposed to approving it as a biosimilar and an interchangeable biologic. Without the interchangeable biologic designation, payers cannot substitute one for the other although doctors can choose to prescribe Zarxio or Neupogen. The FDA standard for interchangeability status has requirements that go beyond showing similarity between the biosimilar and the product it mirrors.

The pharmaceutical industry is somewhat torn when it comes to these lookalike drugs, simultaneously cultivating biosimilar pipelines while also fighting attempts to permit biosimilar-for-branded-biologic swapping. The anti-biosimilar efforts include attempts to persuade states to prevent swapping and asking for distinct international proprietary names that would mean different names appear in parentheses after a brand name and a biosimilar name. That’s different than the generic drug sector, where brand-name Tylenol is called Tylenol (acetaminophen) and the generic version is also referred to as acetaminophen.

Anti-biosimilar efforts also include advocating that biologics should have different independent names because the nature of the products makes creating an almost-carbon copy of a biologic impossible, unlike generic drugs, which rely on common active ingredients with brand-name drugs.

At the same time, major pharma companies are lining up for a slice of the biosimilars business. Amgen, the possible loser as a result of Friday’s approval, has a biosimilars pipeline that includes lookalikes of AbbVie’s Humira and Roche’s Avastin. In an October 2014 business review Amgen projected that its lineup of nine biosimilar contenders could earn $3 billion in annual sales were they all to reach market.

Getting nine contenders regulatory approval may be a while off. The FDA said in a Friday conference call that drugmakers have officially filed four biosimilar applications with the regulator, in addition to Zarxio.

This is not the first time Amgen’s Neupogen has faced a competitor. The FDA approved Teva’s Granix (tbo-filgrastim) in 2012 for severe neutropenia, but the approval was as a biologic, as opposed to a biosimilar, and it had a single indication, unlike Zarxio.

Amgen CEO Robert Bradway told investors during a Jan. 27 conference call that its 2015 earnings projections assumed Novartis’s biosimilar could eat into sales of Neupogen. Novartis told MM&M in an email that it could not share roll-out plans so it is unclear when the fight over patients will begin. 

Even with the FDA’s endorsement and cost-savings arguments, like Rand Corp.’s prediction that the overall biosimilars market could result in $44.2 billion in savings between 2014 and 2024, or 4% of what the US spends on biologics, makers of biosimilars have to convince doctors the drugs are worthwhile.

The industry-supported Tufts Center for the Study of Drug Development released a report just yesterday that showed that the industry will have to convince doctors to accept biosimilars as comparable treatments to the branded biologics they mirror.

During the October presentation Amgen said one way to get doctors to trust biosimilars is to bring the company, not the brand, to the fore to make doctors comfortable with the firm’s “deep biologics scientific skills and strong biologics manufacturing heritage.”