Alendronate plus alfacalcidol yields BMD increases in myasthenia gravis patients
Combination therapy with alendronate plus alfacalcidol appears to produce significant increases in bone mineral density (BMD) and reductions in bone turnover biomarker levels, and to lower the rate of hypercalciuria in myasthenia gravis (MG) patients who initiated treatment with glucocorticoids, according to a study.
The open-label study included 75 MG patients who were treated with 0.25 μg of alfacalcidol every other day and 600 mg of calcium daily. Patients with baseline BMD T-score of less than –1.0 received add-on 70 mg of alendronate per week (alendronate group), whereas those with T-score of greater than –1.0 did not (alfacalcidol-alone group).
Results revealed significant improvements in the alendronate group after 12 months of treatment. Specifically, mean BMD increased by 3.4 percent at lumbar spine (p=0.002), by 1.8 percent at femoral neck (p=0.21), and by 2.6 percent in the total hip region (p=0.02).
However, alfacalcidol monotherapy failed to prevent bone loss in MG patients. The mean BMD in the alfacalcidol-alone group decreased by 6.1 percent at lumbar spine, by 3.2 percent at femoral neck, and by 3.3 percent in the total hip region (p<0.001 for all).
In terms of safety, researchers noted a high incidence of hypercalciuria (≥7.5 mmol/24 hour) even after adjusting the dose of alfacalcidol or calcium supplements (40.9 percent in the alendronate group vs 50.9 percent in the alfacalcidol-alone group; p=0.46). At 12 months of treatment, hypercalciuria events were reported in only 10.5 percent in the alendronate group compared with 44.2 percent in the alfacalcidol-alone group.There were no reports of osteonecrosis of the jaw, atypical fracture, and renal function impairment.