Circulating noggin levels following treatment with denosumab or teriparatide in postmenopausal women with low bone mass

Objectives: Noggin inactivates bone morphogenetic proteins (BMPs), possibly exerting negative effects on the skeleton. We aimed to compare the effect of agents with opposite impact on bone turnover on noggin circulating levels. Methods: In this observational, open label, non-randomized clinical study postmenopausal women with low bone mass were treated with either denosumab (n=30) or teriparatide (n=30). Serum samples were obtained at baseline, three and twelve months after treatment initiation. Prevalent fractures were recorded at baseline and lumbar spine bone mineral density (LS BMD) was measured at baseline and twelve months. Measured parameters included noggin, BMP-2, BMP-4, procollagen type 1 N-terminal propeptide (P1NP) and C-terminal cross-linking telopeptide of type 1 collagen (CTx). Results: Noggin levels remained unchanged after either denosumab or teriparatide treatment. Baseline noggin levels were not different between women with vs. without previous anti-osteoporotic treatment, or between those with vs. without vertebral or non-vertebral fractures and were not correlated with age or LS BMD. At twelve months, noggin levels were positively correlated with P1NP within the denosumab (r(s) = 0.47; p=0.014), whereas negatively within the teriparatide group (r(s) = -0.43; p=0.019). Conclusions: In postmenopausal women with low bone mass noggin levels were not correlated with bone parameters at any time point, except with P1NP at 12 months, and remained stable with both denosumab and teriparatide treatment.