What outcome demonstrated the efficacy of abaloparatide in males with osteoporosis in the Abaloparatide for the Treatment of Men with Osteoporosis (ATOM) study?

Efficacy of Abaloparatide in Males with Osteoporosis: ATOM Study Findings

The Abaloparatide for the Treatment of Men with Osteoporosis (ATOM) study demonstrated the efficacy of abaloparatide in males with osteoporosis based on significant increases in bone mineral density (BMD). 1

Primary Outcome: BMD Improvements

The ATOM study was a randomized clinical trial that evaluated abaloparatide compared to placebo in men with osteoporosis. The study findings showed:

• Primary endpoint: Significant increase in lumbar spine BMD

  • Abaloparatide group: 8.48% increase from baseline
  • Placebo group: 1.17% increase from baseline
  • Statistical significance: p<0.0001 1

• Key secondary endpoints: Significant increases in BMD at other skeletal sites

  • Total hip: 2.14% increase with abaloparatide vs. 0.01% with placebo (p<0.0001)
  • Femoral neck: 2.98% increase with abaloparatide vs. 0.15% with placebo (p<0.0001) 1

Study Design and Population

The ATOM study included:

• 228 men aged 40-85 years with osteoporosis
• Randomized 2:1 to abaloparatide 80 μg daily subcutaneous injections or placebo
• Treatment duration of 12 months
• Mean age of participants: 68.3 years
• Mean baseline lumbar spine BMD T-score: -2.1 1

Clinical Significance

The BMD improvements demonstrated in the ATOM study are clinically meaningful because:

1. The European Society for Clinical and Economic Aspects of Osteoporosis (ESCEO) guidelines specifically cite the BMD data from abaloparatide as supporting its use in men with osteoporosis 2

2. The ESCEO guidelines state: "For those men who would benefit from initial bone-forming therapy, the available data on BMD supports the utility of abaloparatide" 2

3. Based on these findings, abaloparatide is considered "an appropriate first-line treatment for men with osteoporosis at a very high risk of osteoporotic fracture" 2

Important Considerations

• Fracture outcomes: While the ATOM study demonstrated significant BMD improvements, it was not powered to show fracture reduction, which is the ultimate clinical outcome of interest for osteoporosis treatments

• Treatment sequence: For optimal outcomes, anabolic agents like abaloparatide should typically be followed by antiresorptive therapy to maintain BMD gains 3

• Treatment duration: Anabolic agents like abaloparatide have a recommended treatment duration of 18-24 months due to safety concerns with prolonged use 3

• Patient selection: Abaloparatide is most appropriate for men at very high fracture risk, defined as those with prior osteoporotic fracture, BMD T-score ≤-3.5, or FRAX 10-year risk of major osteoporotic fracture ≥30% or hip fracture ≥4.5% 3

Safety Profile

The safety profile of abaloparatide in men was consistent with previous studies in women:

• Most common adverse events (≥5%): injection site reaction, dizziness, nasopharyngitis, arthralgia, bronchitis, hypertension, and headache 1

In conclusion, the ATOM study demonstrated that abaloparatide significantly increases BMD at multiple skeletal sites in men with osteoporosis, establishing it as an effective anabolic treatment option for this population.