When can a patient start Evenity (romosozumab) after receiving intravenous (IV) Reclast (zoledronic acid)?

Timing of Evenity (Romosozumab) After IV Reclast (Zoledronic Acid)

Patients should wait at least 12 months after receiving IV Reclast (zoledronic acid) before starting Evenity (romosozumab) therapy to ensure optimal efficacy and safety.

Understanding the Medications

• Zoledronic acid (Reclast) is a potent bisphosphonate that inhibits osteoclast-mediated bone resorption with a long half-life in bone and duration of action that allows for once-yearly administration 1
• Romosozumab (Evenity) works through a completely different mechanism as a monoclonal antibody targeting sclerostin, which both increases bone formation and decreases bone resorption 2

Rationale for Waiting Period

• Bisphosphonates like zoledronic acid have a long half-life in bone tissue, with effects persisting for months after administration 1, 3
• Starting romosozumab too soon after zoledronic acid may result in:
  • Potential overlap of antiresorptive effects that could theoretically reduce the bone-forming benefits of romosozumab 2
  • Increased risk of adverse effects, particularly since both medications can affect calcium metabolism 4

Safety Considerations

• Before initiating Evenity after Reclast, ensure:
  • Hypocalcemia has been corrected, as this is a contraindication for both medications 4
  • Renal function is adequate, as severe renal impairment (creatinine clearance <35 mL/min) is a contraindication for zoledronic acid and could affect safety of sequential therapy 4
  • Patient has no history of osteonecrosis of the jaw (ONJ), as this is a rare but serious complication associated with both antiresorptive therapies 5

Monitoring Requirements

• Prior to starting Evenity after previous Reclast therapy:
  • Check serum calcium levels 4, 6
  • Assess renal function with serum creatinine measurement 4
  • Consider baseline dental evaluation to minimize risk of ONJ 7

Special Considerations

• For patients with moderate renal impairment (creatinine clearance 30-60 mL/min), additional caution is warranted when transitioning between these therapies 4
• The optimal timing may need to be extended beyond 12 months in patients who have received multiple doses of zoledronic acid previously 6

Alternative Approaches

• For patients who cannot wait 12 months between therapies due to high fracture risk:
  • Consider alternative bone-forming agents that have more established sequential therapy protocols 6
  • Ensure close monitoring of calcium levels and renal function if earlier transition is deemed necessary 4

By allowing adequate time between zoledronic acid and romosozumab, you can maximize the unique bone-forming benefits of romosozumab while minimizing potential adverse effects from overlapping antiresorptive activity.