Background

Osteoporosis (OP) was a systemic bone disorder characterized by low bone mass, increased bone fragility, and fracture susceptibility defined in a consensus development conference in 1993 [1]. It has been a global burden for the elderly. Over 200 million people are thought to be affected by osteoporosis worldwide [2]. According to the International Osteoporosis Foundation, one in every three women over 50 years and one in every five men may have an osteoporotic fracture during their lifetimes [3]. Bone mass density (BMD) is recommended to diagnose OP. OP and osteopenia were defined as having a T score of BMD less than − 2.5 and between − 1 and − 2.5, respectively [1, 4]. Fracture Risk Algorithm (FRAX) scoring is commonly recommended to assess the risk of fractures [5, 6]. Bone turnover markers (BTMs) assess bone remodeling [7, 8]. The majority of bone osteoid is composed of type I collagen. Therefore, BTMs are associated with type I collagen activity. Type I collagen degradation (CTX‑I and NTX‑I) and synthesis (PICP and PINP) are widely used as bone resorption markers and formation markers, respectively [9]. The objectives of OP treatment are to increase bone mass and prevent fractures [10]. The drugs used to treat OP are classified as anabolic and anti-resorptive drugs [11, 12]. The anti-resorptive drugs include bisphosphonates, raloxifene, tibolone, and denosumab. The anabolic drugs include teriparatide (parathyroid (PTH) hormone analogue) and abaloparatide (human PTH hormone-related peptide analogue) [10]. Both anabolic and anti-resorptive drugs have their limitations and adverse effects [4]. Bisphosphonates, the first line treatment for OP, have an issue of drug holidays and atypical femoral fractures [13]. Raloxifene therapy increases the risk of venous thrombosis [14]. Tibolone users had twice the risk of stroke as controls [15]. Denosumab is an anti-resorptive drug, and its anti-resorptive effect rebounds rapidly after discontinuation [16]. It is generally accepted that OP treatment takes a long time. However, the use of anabolic drugs is restricted for up to 2 years due to serious adverse events [101].

Another 1-year romosozumab pre-post study was reported with 262 patients receiving romosozumab (210 mg s.c. Q4W) for 12 months. There were five new fractures reported, but no SAEs were reported. The mean percentage BMD change was 10.67% ± 0.8% (LS) and 2.04 ± 0.6% (TH), compared to the baseline at month 12. sNTX was − 3.70% (at month 1), 0.01% (at month 6), and 3.69% (at month 12) from baseline. iP1NP levels were higher at month 1 (77.34%), at month 6 (50.23%), and at month 12 (27.96%) [102].

The two pre-post studies demonstrated that romosozumab was safe and had a positive clinical effect. However, the follow-up period was short, and the sample size was small. More research is required in the future to comprehend romosozumab.

Conclusion

There is no doubt that romosozumab is a groundbreaking drug in treating OP due to its novel character of inhibiting bone resorption while promoting bone formation. Romosozumab reaffirms the immense value of biomedical applications. For OP patients with a high fracture risk, romosozumab may be more beneficial than other OP medications. In some ways, Romosozumab can replace traditional medications for osteoporosis. However, romosozumab is a new drug that will not only be available until 2019, there is still much room for research in OP. Simultaneously, can romosozumab accelerate delayed healing or ununion, treat secondary OP safely and treat bone tumors? Will other emerging technologies like nanotechnology hold significant potential to impact the field of osteoporosis treatment in the future [103]? Perhaps, there will be answers in the future.