A person's quality-adjusted life years expectancyis calculated based on the amount of life they have left and theexpected condition they will be in during that time.

What is a quality-adjusted life year? It's a metric that hasalready shamed a number of prominent drug-makers into dramaticallylowering the cost of their medications.

One quality-adjusted life year (QALY) represents one year ofperfect health. Thus, a person's QALY expectancy is calculatedbased on the amount of life they have left and the expectedcondition they will be in during that time.

Why is this relevant to medicine? Because the goal of medicationshould either be to prolong life or to improve its quality.

Related: Top 5, bottom 5 countries for life expectancy andwhere the U.S. ranks

The concept has been debated by academics since the 1960's andis most prominently championed by the Institute for Clinical andEconomic Review, a research group affiliated with Harvard MedicalSchool.

In recent years, ICER has been publishing what it considers afair price for drugs based on the number of QALYs they can providea patient.

While no regulatory agencies have adopted the metric in anyofficial capacity, some insurers are embracing it in negotiationswith pharmaceutical companies over drug prices. And in aninteresting twist, some pharma companies have said they will takeit into account, perhaps in hopes of fending off criticism at atime when patients and politicians are eager to crack down on drugprice increases.

"Whatever pricing we believe will be appropriate for a productwill be compared to what ICER did," Dave Lennon, president of theNovartis unit responsible for Zolgensma, explained in an interviewwith the Wall Street Journal.

After initial expectations that Zolgensma would cost as much as$5 million, Novartis agreed to sell it for about $2.1 million. Similarly, the company surprisedthe drug world when it offered to sell its new migraine drug,Aimovig, for only $6,900, down from the $8-10,000 that industryanalysts had projected.

Sanofi SA and Regeneron Pharmaceuticals also agreed to drop thelist price of their cholesterol drug, Praluent, from $14,500 toabout $5,800.

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