Not every genomic breakthrough breeds a blockbuster

Amgen’s just-approved drug, Evenity, has a fascinating scientific backstory.

About 20 years ago, scientists homed in on the cause of a rare disorder that leads to rampant bone growth. It was a single genetic mutation that stops the production of a protein that halts the production of bone. And so Amgen figured that if blocking that protein leads to bone growth in nature, then targeting it with an antibody should improve bone density for postmenopausal women with osteoporosis.

And the company was right. In a pair of large clinical trials, Evenity significantly reduced the risk of bone breaks. But what Amgen didn’t predict was that, in one of those trials, Evenity increased the risk of sudden death, heart attack, and stroke, a result with no clear explanation.

That’s why the FDA rejected the drug in 2017, and it’s why yesterday’s approval comes with a black-box warning advising doctors not to give Evenity to patients who have endured heart attacks and to take serious precaution with those who might be at risk of one in the future.

As a result, the actual use of Evenity is expected to be limited. Wall Street is expecting peak sales of under $300 million a year, a reminder that even when genetics lay out a tidy path, messy biology can still get in the way of turning a scientific breakthrough into an actual product.