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SAN DIEGO -- Treatment with abaloparatide (Tymlos) was safe and effective for men with osteoporosis, according to the phase III ATOM trial.

Compared with a 1.2% increase with placebo, men randomized to receive 80 μg of subcutaneous abaloparatide daily injections for 12 months saw an 8.5% average increase in lumbar spine bone mineral density (BMD, P<0.0001), meeting the study's primary endpoint, reported Neil Binkley, MD, of the University of Wisconsin Osteoporosis Clinical Research Program in Madison.

The trial also met both secondary endpoints, including a significantly greater change from baseline in total hip and femoral neck BMD, he said in a presentation at the American Association of Clinical Endocrinology (AACE) annual meeting:

• Total hip: 2% vs 0% in placebo group
• Femoral neck: 3% vs 0%

"Treatment with abaloparatide resulted in significant and prompt improvements in BMD at the spine, femoral neck, and the total hip," Binkley stated.

Abaloparatide was for the treatment of postmenopausal women with osteoporosis at high risk for fracture, defined as a history of osteoporotic fracture, multiple risk factors for fracture, or failure with, or intolerance of, other available osteoporosis therapy. Approval was based on findings from the and trials.

The bone-building agent acts as a human parathyroid hormone related peptide analog. It comes in single-use prefilled pens to deliver 30 doses of 80 μg subcutaneously once daily into the periumbilical region of abdomen.

The had 149 men randomized to abaloparatide and 79 to placebo. All had primary hypogonadism-associated osteoporosis. Based upon the male reference range, men had to have T-score or -2.5 or less at the lumber spine or hip, or a score of -1.5 or less with a radiological vertebral fracture, or a history of low trauma nonvertebral fracture within the prior 5 years. Participants were eligible if they were over the age of 65 with a T-score of -2.0 or less. On average, men on abaloparatide had BMD T-scores at the lumbar spine, total hip, and femoral neck of -2.1, -1.6, and -2.1, respectively.

All men had to have vitamin D levels of 20 ng/mL or higher, a BMI 18.5-33, and normal levels of calcium, parathyroid hormone, thyroid-stimulating hormone, phosphorus, and alkaline phosphatase.

Those who experienced a severe vertebral fracture or more than two moderate fractures within the past year were excluded. None of the participants could have received treatment with parathyroid hormone, bisphosphonates, or denosumab (Prolia, Xgeva) within the past 18 months.

One week prior to the treatment, all study participants were treated with 500 to 1,000 mg of calcium and 400 to 800 IUs of vitamin D supplementation daily.

When looking at markers of bone turnover, s-PINP and s-CTX were both significantly higher at months 3, 6, and 12 of treatment compared with placebo. After 1 month of treatment, median s-PINP was 111.17 ng/mL and was 85.7 ng/mL by month 12. Median s-CTX was 0.476 at month 6 of treatment and held steady at 0.448 ng/mL by month 12.

The drug was generally well-tolerated, with the most common treatment-emergent adverse events (TEAE) being injection site erythema, nasopharyngitis, and dizziness. A total of 5.4% of those on abaloparatide experienced a TEAE versus 5.1% of placebo, while 5.4% on the study drug discontinued it.

Based on these findings, developer Radius Health filed a with the FDA in March seeking a label expansion to include men with osteoporosis at high risk for fracture. The data will be under review for 10 months.

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