The Food and Drug Administration (FDA) recently approved romosozumab (Evenity), a new drug for osteoporosis. Unlike osteoporosis medicines called bisphosphonates, romosozumab doesn’t just stop bone loss; it also helps build new bone. It’s approved for postmenopausal women who have fractures, are at very high risk for fractures or haven’t responded to other treatments. The drug comes with an FDA warning for an increased risk of heart attack, stroke and cardiovascular death.
Osteoporosis causes bones to become increasingly fragile and prone to break, especially in the spine and hip. The risk for women is higher after menopause, when estrogen levels go down. It’s also higher for men and women who have rheumatoid arthritis (RA), as a result of both the disease and the corticosteroid medications used to treat it, according to Seoyoung Kim, MD, a rheumatologist at Brigham and Women’s Hospital in Boston. Osteoporosis drugs are thought to cut this risk in half.
Romosozumab works by blocking sclerostin – a protein that stops bone from forming. The drug is given by injection once a month for a year (after 12 months, it loses its effectiveness).
In clinical trials, romosozumab increased bone density in the spine as much as 15% – about the amount seen in healthy teens – and cut down on spinal fractures. Patients who switched to a bisphosphonate for another year also had fewer fractures in the wrist and hip.
But Geoffrey Porges, MD, a leading biotech analyst in Boston, points out that the number of hip fractures in the study decreased by only 25%, leaving many women still vulnerable. (According to the CDC, 1 in 5 women die of complications from a hip fracture within a year of their injury.)
There are two other bone-forming osteoporosis treatments – abaloparatide (Tymlos) and teriparatide (Forteo). Both require daily injections for 18 to 24 months and may not build bone as well as romosozumab. But they’re better at reducing nonspine fractures, lowering the risk 43% to 53%.
Costs and Side Effects
Romosozumab costs approximately $21,900 a year ($1,825 a month), comparable to abaloparatide; teriparatide costs almost double, $41,100 a year. Andrew Laster, MD, a rheumatologist at Arthritis & Osteoporosis Consultants of the Carolinas, in Charlotte, North Carolina, says patients must purchase the parathyroid drugs under Medicare Part D, whereas romosozumab is available under Medicare Part B, which should make it affordable for more patients.
He thinks the drug will be best for postmenopausal women who have “multiple Grade 2 or 3 [moderate to severe] vertebral fractures and a low T score [meaning severe osteoporosis] who haven’t been previously treated.”
But Liana Fraenkel, MD, a rheumatologist who studies medical decision-making at the Yale School of Medicine, doesn’t see much point in the drug.
“The only reason a new osteoporosis drug should get any traction is if it doesn’t have the rare side effects of atypical femur fractures and osteonecrosis of the jaw,” she says.
All osteoporosis medications, including romosozumab, are believed to have these potential side effects to some degree; bisphosphonates have the clearest link. Osteonecrosis, which causes bone cells in the jaw to die, occurs in about 1 in every 100,000 people taking a bisphosphonate. Atypical thigh fractures are somewhat more common, ranging from 3.2 to 50 cases per 100,000 patient years, depending on how long the bisphosphonate has been taken.
Slip on Your Sneakers
There are other steps you can take to build stronger bones, such as getting enough calcium and vitamin D, not smoking and not drinking too much alcohol. Exercising is also very important. Doctors recommend a combination of resistance training and weight-bearing exercises like walking or running. Recent studies suggest that other types of activities may prevent bone loss, too, including aerobic dancing and possibly even swimming. The added benefit of this approach is that exercise improves muscle strength and balance, thereby helping prevent falls – the most common reason for osteoporotic fractures.
This summer, researchers at the University of Nebraska and Creighton University’s Osteoporosis Research Center, both in Omaha, will conclude a yearlong trial, comparing how well various treatments prevent bone loss in the first five years after menopause. The treatments include calcium and vitamin D supplements; calcium and vitamin D plus a bisphosphonate; and calcium and vitamin D plus exercise. The researchers say they expect to see the best results in the exercise group.