Treatment of multiple myeloma with etidronate: results of a multicentre double-blind study. Groupe d'Etudes et de Recherches sur le Myélome (GERM).

Objectives: Because osteoclastic bone resorption is stimulated in multiple myeloma, we evaluated the efficacy of etidronate in this disease, in a multicentre controlled study.
Methods: Ninety-four previously untreated patients with stage II or III multiple myeloma received, in addition to the same chemotherapy, 10 mg/kg/day etidronate per os (n = 49) or placebo (n = 45) for 4 months. The evaluation was clinical (pain, Karnofsky, survival), biological and radiological. Forty-one patients had iliac bone biopsy before the treatment and 34 patients also at the end of the study. Histologic bone parameters were compared with 49 normal controls.
Results: No statistical difference was found between etidronate and placebo treated patients for clinical, biological and radiological parameters. Compared with controls, pretreatment biopsies showed markedly increased bone resorption and decreased trabecular bone volume. Bone resorption decreased significantly in patients with etidronate compared with those with placebo (p < 0.05).
Conclusion: Though we found no clinical, biological and radiological difference with placebo, etidronate inhibited the increased bone resorption in multiple myeloma.