Introduction  

Romosozumab is an anti-sclerostin monoclonal antibody used for its potent osteoanabolic effects for the treatment of osteoporosis (1, 2). In the largest trials of romosozumab (FRAME(1) and ARCH(2)), injection site reactions (ISR) were reported in 5.2% and 4.4% respectively. Despite ISRs being listed as a common adverse reaction in the product information, only a single case has been reported to the Australian Therapeutic Goods Administration (3). Similarly, there is only a single published case report of a severe local cutaneous adverse reactions which resulted in discontinuation of romosozumab(4).  

Case Series 

We report on two patients who experienced localised skin reactions following subcutaneous injection of romosozumab. Patient 1 experienced localised erythema and warmth following her 5th dose of romosozumab. The pharmaceutical company was contacted and did not provide recommendations on management. In consultation with dermatology, patient 1 was managed with antihistamine, rotation of injection sites and optimisation of medication temperature. Patient 2 experienced erythema and warmth at the injection site following her 2nd injection and was managed with anti-inflammatories. Both patients completed their planned courses of romosozumab with an overall reduction in the severity of ISR with subsequent doses. 

Conclusion  

ISRs to romosozumab are likely under-reported in the real-world setting and there is currently no guidance on the best management strategy. We share our experience of two patients who safely continued treatment with supervised management.