There’s a new kid in town when it comes to osteoporosis drugs. Meet abaloparatide, brand name Tymlos, which was approved by the FDA on April 28, 2017. If you haven’t heard of it yet, you likely will soon, as manufacturer Radius Health is intent on marketing it until it’s also the most popular kid in town. Most likely, you’ll hear claims of the many benefits Tymlos can provide to women who have severe osteoporosis, without much mention of the trade-offs.
The National Women’s Health Network believes women have a right to know the potential benefits and risks of osteoporosis treatment, so we took a firsthand look at the evidence. We’ve compiled a quick fact sheet about the drug so you can get the unbiased truth about how it works, how it was approved, and how effective it may be at preventing fractures.
What Is Tymlos and How Well Does It Really Work?
Tymlos is an injectable therapy manufactured by Radius Health. It is only approved for use in patients with severe osteoporosis, defined as history of osteoporotic fracture, multiple risk factors for fracture, or patients who have exhausted all other available osteoporosis treatments.
Tymlos is administered once daily by a subcutaneous (just below the skin) injection into the periumbilical region (the part of the stomach right around the belly button).
Tymlos is not the first drug of its kind. Eli Lilly’s hormone drug teriparatide, brand name Forteo, was approved by the FDA in 2002. Tymlos is lab-made copy of part of the human parathyroid hormone-related protein (or PTHrP), while Forteo is partial copy of parathyroid hormone. In our bodies, the PTHrP and the parathyroid hormone do many things, notably stimulating bone cells called osteoblasts to produce new bone tissue. The drugs mimic these natural processes to build bone. This distinguishes them from another category of osteoporosis drugs called bisphosphonates, which work by stopping the destruction of bone material by cells called osteoclasts.
Tymlos does not build bone indefinitely. Tymlos, like Forteo, is only recommended for two years of use. After two years, and sometimes even sooner, the drug’s effectiveness stalls while side effects escalate. Patients are supposed to follow up Tymlos treatment by using bisphosphonates for several years to maintain bone density gains.
Radius Health will boast that their Tymlos drug reduces the relative risk of new vertebral fractures by 86% and also lessens the chance of nonvertebral fractures by 43% .,  These numbers look large, but using relative risk to assess a drug’s impact can be deceiving. Relative risk can make very small reductions look very large, which is exactly what happened in this study. According to the report, 4.7% of patients given placebos had nonvertebral fractures compared to 2.7% of patients taking Tymlos. That’s actually just a 2% absolute reduction in nonvertebral fractures, a vastly different number than the 43% relative reduction that Radius Health boasts. There was only a 3.6% absolute reduction in vertebral fractures between placebo and Tymlos groups. In order to be approved, by the FDA, Tymlos simply had to prove that it was just as effective at stimulating bone growth as its predecessor, Forteo. This is important to note, because the NWHN was already critical of the high risk and low returns from studies on Forteo. When the FDA approved Forteo, it set the bar pretty low for approval of similar drugs.
Tymlos carries a label warning against osteosarcoma, or bone cancer. This is because Forteo, which activates the same biological pathways as Tymlos, was shown to cause bone cancer in animal studies.,  Other side effects of Tymlos include nausea, dizziness, and vomiting.
Tymlos isn’t cheap. The price tag comes out to $19,500 per year. This is less than the current cost of Forteo, but Forteo’s price trajectory is instructive: Eli Lilly has raised its price twice per year (by 9 to 15 percent each time) since its launch.
So How Do We At the NWHN Feel About Tymlos?
Be cautious when you hear news about a new osteoporosis “miracle drug.” Tymlos is being heralded as a major improvement over teriparatide, and this hype is likely to escalate as Radius Health begins to market the drug. However, this hype is largely unfounded. Tymlos only showed slight improvement in bone mass density and even slighter improvement in reducing fracture rates compared to Forteo in clinical trials. Although side effects are rare, they may include aggressive bone cancer. Additionally, the treatment is expensive, and insurance companies could be reluctant to cover it, just as they are with Forteo.
It is also important to remember that this treatment is only recommended for women with very severe osteoporosis. Don’t forget, if your doctor has diagnosed you with osteopenia or mild osteoporosis, there are many ways to increase bone strength other than medication. This includes doing weight bearing exercise for 30 minutes each day and consuming the recommended amount of Calcium and Vitamin D.
For more information on the NWHN’s position on osteoporosis screening and treatments, visit our osteoporosis fact sheet.
Caila Brander is the NWHN Policy Fellow.
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 Radius Health, “FDA Approves Radius Health's TYMLOS™ (abaloparatide), a Bone Building Agent for the Treatment of Postmenopausal Women with Osteoporosis at High Risk for Fracture” [Press release]. Retrieved from http://investors.radiuspharm.com/releasedetail.cfm?releaseid=1023557
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