Once-weekly subcutaneous injections of the osteoporosis drug teriparatide still achieve increases in bone mineral density, according to a postmarketing observational study published online in Osteoporosis and Sarcopenia.
is widely used as a daily, self-injection formula for osteoporosis, but in Japan, a once-weekly injectable formulation of 56.5 ug is also being used in individuals with osteoporosis who are at high risk of fracture.
In a study of 3,573 Japanese patients with osteoporosis, investigators found increases of 2.8%, 4.9%, and 6.1% in lumbar spine bone mineral density measured at 24, 48, and 72 weeks respectively. In the femoral neck, bone mineral density increased by 1.6%, 1.4%, and 2.5% at 24, 48, and 72 weeks, and total hip bone mineral density increased by 1%, 1.6%, and 2.5%.
At 24 weeks, the median percent change from baseline in the level of serum bone formation marker procollagen type I N-terminal propeptide increased 23%, and then decreased to a 4.3% median change at 48 weeks and 8.7% at 72 weeks. There were no significant changes in serum bone-type alkaline phosphatase by 48 and 72 weeks, and no changes at all in the bone turnover markers tartrate-resistant acid phosphate-5b and cross-linked N-terminal telopeptide of type I collagen.
Researchers also saw reductions in low back pain scores at all the time points, although the authors noted that the mechanism of this association was not well understood and needed further study.
“The results for efficacy parameters, including fracture incidences, in this surveillance were as expected based on the clinical studies prior to approval, indicating that the medical benefits of teriparatide were demonstrated in actual clinical practice after marketing,” wrote Dr. Emiko Ifuku and colleagues from Asahi Kasei Pharma, which manufactures the drug in Japan.
The study also looked at adherence to the once-weekly therapy, and found that 59.4% of patients were still taking the treatment at 24 weeks, and 39% were taking it at 72 weeks.
Around a quarter of patients experienced adverse reactions, with the most common being nausea (12.3%), vomiting (2.8%), headache (2.7%), and dizziness (2.2%) and most occurring within 24 weeks of starting treatment. Serious adverse reactions were reported in 26 patients (0.7%).
Asahi Kasei Pharma sponsored the study. All of the authors were employees of the company.
SOURCE: Ifuku E et al. Osteoporos Sarcopenia. 2019 Jun 26.