A new study suggests that using osteoporosis medications romosozumab and zoledronate one after another may significantly increase the risk of medication-related osteonecrosis of the jaw (MRONJ). Researchers found more severe bone damage in mice treated with this drug sequence. The findings call for doctors to carefully consider this treatment approach for patients.
Study Reveals Increased Jaw Bone Necrosis
The recent study aimed to understand the occurrence of MRONJ in mice after they received romosozumab followed by zoledronate. Researchers divided 35 female C57BL/6 mice into three distinct groups. One group received romosozumab, then zoledronate, which scientists labeled as the ROM+ZOL group. A second group received saline, followed by zoledronate (ZOL group), while a control group received only saline.[medicaldialogues+5]
Following the drug administrations, researchers performed maxillary first molar extractions on all mice. This simulated a common dental procedure that can sometimes trigger MRONJ. The ROM+ZOL group showed much more severe bone necrosis compared to both the ZOL group and the control group. This group also had a lower bone volume fraction and fewer sclerostin-positive cells, indicating heightened bone death when romosozumab was given before zoledronate. Laboratory tests also confirmed that both zoledronate and romosozumab effectively stopped osteoclast differentiation and function on their own. The study authors emphasize that these results highlight the critical need for careful consideration when using this sequential drug therapy in clinical practice.[medicaldialogues+9]
Understanding Medication-Related Osteonecrosis of the Jaw
Medication-related osteonecrosis of the jaw, or MRONJ, is a rare but serious condition. It involves exposed bone in the jaw that fails to heal for more than eight weeks, often after a dental procedure. Patients with MRONJ can experience pain, swelling, infection, and numbness in the jaw, significantly impacting their quality of life. Various factors can increase a person's risk of developing MRONJ. These include being over 65 years old, having gum disease (periodontitis), maintaining poor oral hygiene, and undergoing dentoalveolar surgery like tooth extractions. High doses or prolonged use of antiresorptive agents, typically for more than two years, also raise the risk.[ada+3]
Osteoporosis is a widespread bone disease that makes bones weak and brittle, greatly increasing the chance of fractures. Millions of people worldwide live with this condition. Medications like romosozumab and zoledronate are important tools for doctors treating osteoporosis. Zoledronate, a type of bisphosphonate, works by slowing down the activity of osteoclasts, which are cells that break down bone. This helps to preserve bone mass and strength.[medicaldialogues+3]
Romosozumab, sold under the brand name Evenity, is a newer treatment approved in 2019 for severe osteoporosis. It is a monoclonal antibody that targets sclerostin, a protein that naturally inhibits bone formation. By blocking sclerostin, romosozumab has a unique "dual effect": it both increases new bone formation and reduces existing bone breakdown. This dual action allows for rapid bone building, often referred to as an "anabolic window". However, romosozumab's bone-building effects typically lessen after about 12 months of treatment. Because of this, doctors often follow romosozumab therapy with another antiresorptive drug, such as zoledronate or denosumab, to maintain the bone density gains achieved.[ada+14]
Sequential Therapy Creates New Concerns
The study's findings suggest that the sequential use of romosozumab followed by zoledronate creates an "extremely low bone turnover" state. While romosozumab initially boosts bone density through its dual action, the subsequent administration of zoledronate, a potent antiresorptive, significantly halts osteoclast activity. This severe reduction in bone remodeling activity can impair the body's natural healing process, especially after traumatic events like tooth extractions. Without adequate bone remodeling, necrotic bone tissue cannot be cleared, and extraction sockets may not heal properly, leading to the development of MRONJ lesions.[omnicuris+3]
Previous research has indicated that romosozumab alone carries a low risk of MRONJ, comparable to that of bisphosphonates, ranging from 0.03% to 0.05%. Data from the FDA's Adverse Event Reporting System (FAERS) also showed a slight increase in MRONJ risk associated with romosozumab treatment. However, the new mouse study highlights that the sequence of these two specific drugs may exacerbate this risk beyond what is seen with either drug individually.[aaoms+4]
Clinical Implications for Patient Care
The results of this study carry important implications for healthcare professionals managing osteoporosis. Doctors must carefully weigh the significant benefits of increased bone density provided by romosozumab and zoledronate against the newly identified potential for a higher MRONJ risk when these drugs are used in sequence. Patient selection and a thorough dental evaluation before starting or transitioning between these therapies become even more critical.[medicaldialogues+1]
"Understanding how these drugs interact during the bone remodeling process is essential for preventing severe complications following invasive dental procedures," experts note. This underscores the need for close communication between prescribing physicians and dentists. Patients receiving or considering this sequential therapy should inform their healthcare providers about any planned dental work or oral health concerns.[omnicuris]
While sequential therapy with romosozumab followed by zoledronate has proven effective in preserving bone mineral density gains, this new safety concern requires careful consideration. Further studies are likely needed to compare the risk of MRONJ when romosozumab is followed by different antiresorptive agents to guide optimal treatment strategies for patients at high risk of fractures. The findings ultimately reinforce the importance of individualized patient care, where the benefits and risks of each treatment approach are meticulously evaluated.[pmc+1]
