In Europe, the world's top-selling drug faces a shakier future after the entry of four copycat rivals last October quickly led to declining sales.
Across the Atlantic, however, AbbVie's exclusive market for Humira remains intact, even as the Food and Drug Administration has cleared three biosimilar rivals to the multi-use drug. Patents protect AbbVie's drug, and settlement deals mean the earliest arrival of a lower-cost copycat won't be until 2023.
It's a familiar story in the U.S., which lags Europe in the number of biosimilars available. Nineteen have been approved in the U.S., but only seven are available. Legal defenses play a major role, as does physician and patient reluctance to use those that are for sale.
With little impact to date, a few experts are calling for the U.S. to abandon biosimilars altogether, and regulate prices for biologic drugs instead.
Unsurprisingly, Christopher Ko, head of the Korean biosimilar maker Samsung Bioepis, thinks this is unwarranted.
"People are too impatient with the current launch status of biosimilars," Ko said in an interview with BioPharma Dive this month. "Market shaping takes time."
Ko noted Europe is nearly a decade ahead of the U.S, where a regulatory framework for biosimilars was set up in 2009 and the first approval was granted in 2015. More than 50 biosimilars are currently authorized for sale in EU countries.
"As those numbers become equalized, I think we will see just as attractive a market in the U.S. as we have seen in Europe," he added.
Skeptics argue even Europe's experience with biosimilars doesn't support hopes the copycat biologics will deliver substantial cost savings.
"In Europe, over a longer experience beginning in 2006, there are many products that still have no biosimilar competition," wrote researchers, including Memorial Sloan Kettering's Peter Bach and MIT Sloan's Mark Trusheim, in a recent Health Affairs article.
"Among those that do, price declines have averaged around 30 percent, a savings that evolves on average at 3.5 percent per year following biosimilar entry."
In the U.S., discounts to branded biologics — the main draw of biosimilars — have ranged between 15% and 35% at launch, well above the 80% to 90% discount usually seen with generic copies of small molecule pharmaceuticals.
However, to Ko's point, research by the Food and Drug Administration found such generic discounts only emerge after several low-cost versions of the target branded drug have entered the market.
Of the seven biosimilars available in the U.S., two reference J&J's Remicade and two each reference Amgen's Neupogen and Neulasta, respectively, suggesting potential for greater price competition to emerge as more biosimilars launch.
But there will likely be a limit to the discounts biosimilars can offer. In contrast to generic drugs, biosimilars take longer to develop and are more costly to manufacture.
"I don't ever see a situation with [the gap between] biologics versus biosimilars becoming like that of small molecules generics," said Samsung's Ko. "Fundamentally these are two different classes."
Additionally, the FDA has yet to approve a so-called interchangeable biosimilar, which would allow pharmacists to substitute the lower-cost version even when the branded drug is prescribed — as is the case with generics.
For biosimilar products used in hospitals, interchangeability may not spur higher adoption, but the designation could prove a tailwind to the lower-cost drugs that reference biologics used at home.
The FDA recently published final guidance on interchangeability standards, giving biosimilar makers clarity on what would be required.
Yet winning an interchangeable designation presents companies with a choice.
"Do we launch in Europe first without having done an interchangeability study?" said Ko. "Or do we do one study that includes the requirements for FDA interchangeability, but that means the European launch can be delayed?"
Ko noted that the studies required to demonstrate interchangeability, which involve switching patients between branded product and biosimilar, are expensive and take more time.
Branded biologic makers have also used interchangeability as a tool in marketing against switching to biosimilar products.
A Janssen website for patients on its drug Remicade, for example, compares biologics and biosimilars to two similar, but not identical snowflakes.
J&J's practices in marketing Remicade are the subject of a lawsuit by Pfizer, which sells a Remicade biosimilar and argues J&J engaged in exclusionary contracting and anti-competitive behavior to stall sales of its copycat version.
One tactic in particular, bundling drug rebates together in negotiations with payers, has made it difficult to make inroads with a biosimilar, Pfizer argued.
Ko shared similar worries, noting the difficulties of competing on price without knowing the net price reached in negotiations between branded drugmakers and payers.
"With the rebate system in the U.S., we want to make a competitive offer and we're willing to do that," said Ko. "But we don't know what the price is because it's not transparent."
A proposed rule by the Trump administration to ban drug rebates from drugmakers to payers in government insurance plans could help, Ko said, if net prices become more transparent as a result. The proposal is currently under review at the Office of Management and Budget, a step that precedes finalization of the rule.
This year could prove an important one for biosimilars in the U.S., with competition expected to begin this year for several of Roche's top cancer drugs.
Five biosimilar versions of one, called Herceptin, are already approved, potentially making it a test case for how quickly biosimilars can impact branded drug sales and deliver savings.
Proving success could go some ways to allaying concerns of biosimilars future in the U.S.
"If there's not a demonstration that you can launch a new biosimilar successfully commercially, you could have the risk that more manufacturers either pull out of this market, or don't get into it in the first place," noted former FDA Commissioner Scott Gottlieb in a March interview with BioPharma Dive.