To assess the clinical efficacy and equivalence of a daily vs alternate day regimen, and the potency ratio between 2 glucocorticoids, deflazacort and 6-methylprednisolone.
Thirty-one patients with recent onset polymyalgia rheumatica (PMR) were randomly assigned to deflazacort (n = 16) or 6-methylprednisolone (n = 15), according to a 2 period (duration of each period = 6 weeks), crossover, open design for comparing 2 dose regimens (daily vs alternate day), and according to a between-patients, double blind design for comparing the therapeutic effects of the 2 glucocorticoids (deflazacort vs 6-methylprednisolone). The patients, either during alternate day or daily regimen, were treated with fixed oral doses for the first 2 weeks (assuming a potency ratio deflazacort/6-methylprednisolone of 1.5 mg/1.0 mg: deflazacort 24 mg or 6-methylprednisolone 16 mg, daily; deflazacort 48 mg or 6-methylprednisolone 32 mg, alternate day), and with titrated doses for the next 10 weeks.
Two patients dropped out during the first 6 week period. The time course and extent of the improvement of disease activity indices (limb-girdle pain, morning stiffness, erythrocyte sedimentation rate, C-reactive protein, and plasma fibrinogen) were not statistically different under the 2 regimens. The satisfactory equivalent glucocorticoid response observed in 12 pairs of patients treated with deflazacort and 6-methylprednisolone progressed significantly from baseline to the end of the study, under daily or alternate day regimen, with no significant difference between the 2 glucocorticoids. Deflazacort proved less potent than 6-methylprednisolone (1.78 mg: 1.0 mg minimum effective daily dose; 1.68: 1.0, alternate day), but equally effective.
The 2 dose regimens, 6-methylprednisolone and deflazacort showed no significant differences in terms of efficacy during the short term treatment of PMR. Deflazacort proved less potent than initially estimated.