Old Drugs Usually Go Way Down in Price. This One Skyrocketed

When Jean Kay started a brand-new multiple sclerosis treatment called Rebif in 2003, it cost $17,500 a year. That was pricey, but her insurance covered most of it, and the drug slowed the disease’s progress, improving her life immeasurably. Since then, though, the price of Rebif has risen four times faster than the rate of inflation, to more than $140,000 annually—with the share she’s had to pay bouncing up and down over the years until 2024, when her insurer decided to stop covering it at all.

Illustration: Baptiste Virot for Bloomberg

For decades, paying for treatment has influenced Kay’s career choices, led her husband ...