Tumour-induced hypercalcaemia

Prior to treatment with ibandronic acid the patient should be adequately rehydrated with 9 mg/ml (0.9%) sodium chloride solution. Consideration should be given to the severity of the hypercalcaemia as well as the tumour type. In general patients with osteolytic bone metastases require lower doses than patients with the humoral type of hypercalcaemia. In most patients with severe hypercalcaemia (albumin-corrected serum calcium* ≥3 mmol/l or ≥12 mg/dl) 4 mg is an adequate single dose. In patients with moderate hypercalcaemia (albumin-corrected serum calcium <3 mmol/l or <12 mg/dl) 2 mg is an effective dose. The highest dose used in clinical trials was 6 mg but this dose does not add any further benefit in terms of efficacy.

* Note albumin-corrected serum calcium concentrations are calculated as follows:

Albumin-corrected serum calcium (mmol/l) = serum calcium (mmol/l) - [0.02 x albumin (g/l)] + 0.8

Or

Albumin-corrected serum calcium (mg/dl) = serum calcium (mg/dl) + 0.8 x [4 – albumin (g/dl)]

To convert the albumin-corrected serum calcium in mmol/l value to mg/dl, multiply by 4.

In most cases a raised serum calcium level can be reduced to the normal range within 7 days. The median time to relapse (return of albumin-corrected serum calcium to levels above 3 mmol/l) was 18-19 days for the 2 mg and 4 mg doses. The median time to relapse was 26 days with a dose of 6 mg.

A limited number of patients (50 patients) have received a second infusion for hypercalcaemia. Repeated treatment may be considered in case of recurrent hypercalcaemia or insufficient efficacy.

Ibandronic acid concentrate for solution for infusion should be administered as an intravenous infusion over 2 hours.