The final full text of the Trans-Pacific Partnership (TPP) is out, and it will stir up some debate again over the massive trade deal.

But for those watching how the trade pact might affect the international market for biosimilars, the unveiling of the full text doesn’t seem to mean any big surprises.

Outside of the U.S., the data exclusivity for biologics—which is tantamount to the amount of time before a biosimilar can hit the market—will range from a minimum of five years, with additional years of vaguely defined “other measures,” to a firmer period of eight years of exclusivity.

News reports have said the 12-year standard will remain in effect in U.S., and the summary of the deal that U.S. Trade Representative posted today as part of the release of the full text confirmed that. The trade representative's summary says that none of the provisions pertaining biologics will “change any U.S. healthcare program or the data protection that’s existing in U.S. Law.”

Everyone seems to agree that one of the main hang-ups during the negotiation of the Trans-Pacific Partnership (TPP) trade deal was data exclusivity for biologics, a key factor in determining when biosimilars can get on the market.

But there’s a lot less agreement about what the TPP negotiators have actually agreed to. Full text of the agreement is not going to available for several weeks, so in the meantime there’s plenty of room for interpretation.

Biosimilars will probably not take the United States pharmaceutical market by storm but they may find faster acceptance here than they did in Europe, one expert tells the Wall Street Journal. Kate Keeping of the research company Decision Research Group says that U.S. physicians are much more familiar with biosimilars than European physicians had been before biosimilars were launched there. “It’s less likely that you’re going to see restrictions on uptake due to physicians being hesitant,” she tells the WSJ.

Maybe. But maybe it’s a systematic problem. Ronny Gal, an analyst at Sanford C. Bernstein, tells the newspaper that countries with a strong central health care payer tend to take to biosimilars faster than those that lack such central control. In that case, doctors must decide.

Sandoz, a unit of Novartis, this month launched Zarxio, a biosimilar of Amgen’s biologic Neupogen, which fights infections in cancer patients. Zarzio, the European version of Zarxio, has been in that market since 2008. It’s 10% to 30% cheaper than Neupogen, in contrast to 80% to 95% discounts for generics of small-molecule drugs.

Biosimilars supporters argue that they “could still bring significant cost savings since the drugs they copy are so expensive to begin with.”

Again, much hinges on physician buy-in, not always a sure thing, as a recent survey of gastroenterologists illustrates. 

Milliman predicts that it will be at least 12 years before biosimilars fully penetrate the market in the United States. But the consulting company tells employers that the U.S. market could possibly evolve the same way that it has in Europe, where biosimilars have a healthy presence.

The 15 percent discount is the same price gap set when Zarxio was launched in Europe in 2009, although the discount in Europe has since widened to an average of around 20 to 30 percent.

Insurers hope biosimilars will eventually cost the public 40 percent to 50 percent less than the original brands.

Neupogen is a $1.2 billion-a-year medicine for Amgen that boosts white blood cell counts to fight infections in cancer patients. The majority of its sales are generated in the United States.

Physicians wonder about the efficacy of biosimilars and worry about the fine print in drug substitution laws, according to a survey by Quantia, an online discussion platform for about 225,000 doctors.

The U. S. has lagged behind the rest of the world as far as biosimilars are concerned. Biosimilars have on the market in Europe since 2006 and they are commonly in China, India, and South Korea.

But the FDA approved the first biosimilar, filgrastim-sndz (Zarxio), on March 6, 2015, and now analysts are busy predicting how large the U.S. market will be.

Most physicians are aware of biosimilars, but ask them to name one and many come up short, according to a survey of 300 specialists and primary care physicians conducted by QuantiaMD, an educational website for physicians.

The survey results, as published in Medical Marketing and Media, show that 78% of the doctors who answered questions about biosimilars were familiar with the term.

How physicians view biosimilars is one of the wildcards that will determine how popular the drugs become.

Gastroenterologists are especially important group because anti-TNF biologics, infliximab (Remicade) and adalimumab (Humira) are commonly prescribed for inflammatory bowel disease.

Generic versions of small molecule drugs have generated a trillion dollar-plus in savings, by some accounts. People who care about health care costs are hoping that biosimilars might also ratchet down the country’s health care bill by a notch or two—maybe not in that trillion dollar range but by enough to make a notable difference.

But obstacles loom in the way of a biosimilar windfall, as outlined today in an opinion piece in JAMA by Amitabh Chandra, director of health policy research at Harvard’s Kennedy School of Government, and Jacqueline Vanderpuye-Orgle, director of research operations at Precision Health Economics. They mention two. First, biosimilars are, in fact,  merely similar to their brand-name counterparts, argue Chandra and Vanderpuye-Orgle, so they can’t necessarily be marketed as producing the same results as their referenced products. Second, the manufacturing process for biologics is complex—more complex than it is for small molecule drugs—and the costs are high, so entry into the market won’t be easy. Difficult market entry may mean less competition.

Lower your expectations, say Chandra and Vanderpuye-Orgle:

"The likely preference for the approved original biologic product (or reference biologic) and limited competition suggest that biosimilars will have less effect on the marketplace than generic products did for branded small molecule drugs."

And expect prescribing physicians to be wary of biosimilars:

"This unease [of prescribing physicians] with using biosimilars is likely large; amplified by risk aversion, status quo bias, and malpractice concerns given the unknown toxicity of the agents; and reinforced by financial considerations if payment to physicians is a fixed percentage of the price of the drug (as in Medicare Part B)."