Let's imagine two cars speeding toward one another ? in one car are branded manufacturers keen on protecting valuable drug franchises, and on the other are payers equally keen on tamping down drug costs, particularly on new specialty medications.

The crash you heard from these two cars was the sound of payers colliding with manufacturers, or in other words, UnitedHealthcare's decision to prohibit manufacturer copay coupons come July of 2014.

Besides being the largest health benefits company in the United States, UHC is also a trendsetter. As long ago as the 1990s, it announced it would get rid of many of the onerous parts of managed care such as prior authorization (only to quietly return to several of them later). It invested millions into healthcare IT and ACOs before others in the industry caught up.

And now, it's declaring war on copay coupons, which have over the past five years become a tactic increasingly used by biopharma companies to get branded drugs into the medicine cabinets of patients. Copay coupons are typically available for drugs on nonpreferred or specialty tiers that require the maximum out-of-pocket expenditure from individuals. In 2014, copay coupons are available on nearly 400 different drugs, representing about 15 percent of branded drug volume.

Payers and pharmacy benefit managers that negotiate rebate contracts with manufacturers believe the coupons undermine their rebating strategy, pushing more consumers into higher-tier choices, but then leaving them hanging once the coupon expires, typically after a year. Manufacturers counter that it gives consumers more choice in affording drugs that they want to take ? regardless of tier status.

UHC recently posted a notice on its website for brokers indicating it planned to ?partner with our network pharmacies to discontinue the use? of copay coupons. Whether all of those networked pharmacies would agree to UHC's move remains to be seen, but the company is driving 13-million-plus commercial lives (those affected by copay coupons) through the system (copay coupons are not allowed in Medicaid and Medicare). For retail pharmacies, it may be difficult to buck UHC. The landscape of copay coupons was already changing with the launch of health benefits exchanges and the uncertain response by manufacturers about whether they planned to pursue this segment of the market. Regulatory guidance remains a bit muddied and several manufacturers were not aggressively offering the coupons to exchange enrollees. On March 26, Bloomberg News reported that Merck and GlaxoSmithKline were not reimbursing drug copayments for patients on exchanges. Amgen, on the other hand, was making a different call, offering the coupons to those enrollees, Bloomberg reported.

For now, the crash scene involves two big industry titans representing Big Pharma and Big Payers. Patients and physicians?two obvious missing pieces in the prescribing chain?are bystanders. That's unlikely to change anytime soon, but as the system grapples with five-figure-annual drug costs for some patients, expect more collisions like this.

Follow Jane DuBose on Twitter @JaneGDuBoseDRG