Merck KgaA Warhorse Defies Logic by Getting Pricier With Age

Merck KGaA is still raising the price on its warhorse of a multiple sclerosis drug, Rebif, almost two decades after the medicine first went on sale.

The cost of Rebif, Merck’s best-selling medicine, went up by 6 percent to about $87,000 a year on Feb. 1, data from FirstDataBank show. That price doesn’t include rebates and discounts. Its German manufacturer may seek another hike in coming months to make up for the dwindling number of patients, but it will wait to see if rival drugmakers with more clout do the same for competing treatments, Chief Financial Officer Marcus Kuhnert said ...