Bloomberg

(Bloomberg) -- Fighting yourself is a losing battle.

A long-cherished hope of some companies that make expensive biologic medications -- complex drugs made with living cells -- is that they were relatively safe from competition because biologics are tougher to copy and replace than traditional drugs. That's looking a bit less true every day. 

In a delightfully incestuous turn, big companies aren't just fighting so-called biosimilar versions of these drugs anymore -- they're making them.

Amgen, which is litigating against biosimilars of its own drugs, is bringing its version of AbbVie's Humira in front of an FDA panel of experts Tuesday. Novartis is doing the same thing Wednesday with its copy of Amgen's Enbrel. The FDA has given fairly glowing reviews to both biosimilars. Humira, with $14 billion in sales last year, and Enbrel, with more than $5 billion, both have substantial patent protection. But competitors hope to chip it away. 

And what was once a chasm between biosimilars and generics is closing into a more modestly daunting crack. 

This is a whole new biosimilar world, as my Bloomberg News colleague Drew Armstrong recently pointed out. Biotechs and pharmas used to argue biosimilars would never be low-price copies of their products, and that doctors would not prescribe them because they were entirely different drugs.

Now Amgen, Novartis, Pfizer and others are in the biosimilar game themselves. And the drugs they're producing are excellent; the FDA is repeatedly finding no clinically meaningful differences in safety, efficacy, purity, or potency between biosimilars and original products.

In several cases now the agency has suggested trial results are good enough to support what's called "extrapolation." That means approving a biosimilar drug to treat all conditions the original product treats without running clinical trials in each disease. That should make approval of these drugs easier and their uptake faster. 

And with big companies producing biosimilars, there's not as much of a concentrated lobbying effort to restrict them as a class. After all, it's tough to argue simultaneously for some biosimilars but against the ones that happen to compete with your own drugs. Companies will continue to use whatever legal remedies they have, as you'd expect when there are tens of billions of dollars at stake. But these are likely stalling tactics at best. 

FDA guidance on how easily biosimilars can be substituted for original products is forthcoming some time this year. Any restrictions are unlikely to last long, given the encouraging trial results so far and the potential for billions in cost savings.

The remaining question is whether doctors will be enthusiastic about switching. They will likely get a forceful nudge in that direction from penny-pinching insurers and pharmacy benefit managers (PBMs). Last year, for example, Humira and Enbrel had 66 percent of inflammation drug market share, according to PBM giant Express Scripts. Drugs in the class cost the PBM an average of $3,095 per prescription. Payers will likely use biosimilars as leverage to aggressively negotiate for lower prices and require patients to pay more out of pocket for pricier options. 

There are limits to the threat of biosimilar competition. Biosmilars are expensive and difficult to make. There are higher barriers to entry financially, scientifically, and with regulators than with generic drugs. And biosimilars are attempting to replace complicated drugs for chronic conditions; physicians may be reluctant to switch stable patients.

But time is the remedy for that. More biosimilars will hit the market as more real-world data on their use and interchangeability are generated. Experience could lead to greater doctor comfort just as more competition becomes available.

That should ratchet up the price pressure on legacy products; Novartis CEO Joe Jimenez expects biosimilars may eventually cost 75 percent less than the products they mimic. 

The once-common argument that biosimilars and generics shouldn't be mentioned in the same breath is dying a quiet and seemingly inevitable death. 

This column does not necessarily reflect the opinion of Bloomberg LP and its owners.

To contact the author of this story: Max Nisen in New York at mnisen@bloomberg.net.

To contact the editor responsible for this story: Mark Gongloff at mgongloff1@bloomberg.net.

©2016 Bloomberg L.P.

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