Express Scripts announced adrastic departure from business as usual: a new drug list forclients that favors drugs with lower sticker prices over those thatprovide huge secret discounts.

Express Scripts Holding Co. and other pharmacy-benefit managers make money bynegotiating drug prices on behalf of health-plan providers. Thelist prices that pharmaceutical companies setfor their drugs diverge wildly from their real cost, and PBMs widenand feast on the gap, which helps make them some of the principalbeneficiaries of America's byzantine pricing system.

But on Tuesday, ahead of its acquisition by Cigna Inc. and possibleregulation, Express Scripts announced a drastic departure frombusiness as usual: a new drug list for clients that favors drugswith lower sticker prices over those that provide huge secretdiscounts. While unlikely to replace the current system any timesoon, it's a substantial shift for a major PBM, and anacknowledgment of tough political and business realities that couldboost a nascent and positive trend in drug prices.

Related: Now comes the hard part for Cigna-Express Scripts:PBM reform

One of the main services PBMs provide are so-called drugformularies, or tiered lists of medicines, where drugs deemed“preferred” are much cheaper than those that are “excluded.”Preferred status on a major formulary can add millions in salesvolume, and drugmakers offer huge rebates in order to secure it.The growing scale of PBMs — Express Scripts's annual revenue hasincreased by $80 billion in the past decade — has contributed to anexplosion in the size of rebates and the so-called gross-to-net gapbetween list prices and the amount that's actually paid.

Critics contend that PBMs reap excessive profits from thisarrangement, and that companies like Express Scripts have createdan incentive for drugmakers to hike prices to offer higher rebates.This, in turn, has prompted regulatory scrutiny, in the form of aplanned Trump administration rule.

The firm's new formulary upends the status quo by creating apath to preferred status for drugs that have lower list prices. Thestrategy was enabled by drugmakers Gilead Sciences Inc. and AmgenInc., which recently announced that they would make their priceyHepatitis C and cholesterol medicines available at a substantiallyreduced list price as they try to boost sales volume in toughmarkets.

That new price is in line with what the drugs previously costafter rebates, so the overall cost to the system may not changemuch. But this is big news for people on high deductible plans aswell as Medicare beneficiaries, who often have out-of-pocketexpenses that are based on the full list price.

This formulary option likely won't be broadly popular to start.List-price competition is very much still the exception, and therebate system is firmly entrenched. Many health-plan sponsorsactually like the status quo, as the rebates result in a big pileof money that they can use flexibly.

But it's still a smart move for Express Scripts. Otherdrugmakers will likely follow Amgen and Gilead into a dual-classdrug pricing structure if the two firms manage to boost salesvolume 1 ; the new formulary from Express Scripts will make thatshift easier. And if the U.S. government follows through on itsplans to regulate rebates, this sort of pricing structure willlikely become even more appealing.

This isn't a panacea for high drug prices. But any step towardcorrecting a major health-care distortion that has a real humancost is a good one.

Read more: 

• Drug price transparency takes a stepforward
• Reference-based pricing: a panacea for high drugprices?
• The best fix for drug prices is already on thebooks

Max Nisen is a Bloomberg Opinion columnistcovering biotech, pharma and health care. He previously wrote aboutmanagement and corporate strategy for Quartz and Business Insider.This column does not necessarily reflect the opinion of theeditorial board or Bloomberg LP and its owners.

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