Two of the biggest pharmaceutical companies in the world did something unusual this week when they announced the introduction of breakthrough drugs: they charged less.

If that sounds odd, it is. Drugmakers typically engage in an upwards race to price new medications above older competitors, arguing that the new treatments are worth more because of better effectiveness or fewer side effects. The result has been upward-spiraling list prices in the U.S.

Sanofi and Regeneron Pharmaceuticals Inc. on Tuesday said its new treatment for atopic dermatitis, a debilitatingly painful skin condition, will cost $37,000 a year. That’s substantially lower than the $50,000-a-year price charged for similar, older drugs, and the companies said they’d held long talks with insurers to avoid yet another blowup over drug pricing.