Intramuscular clodronate in erosive osteoarthritis of the hand is effective on pain and reduces serum COMP: a randomized pilot trial-The ER.O.D.E. study (ERosive Osteoarthritis and Disodium-clodronate Evaluation).

We evaluated the efficacy and safety of intramuscular clodronate (CLO) for the treatment of active erosive osteoarthritis of the hand (EOA). Forty outpatients treated with anti-inflammatory (NSAIDs) or analgesic drugs since at least 6 months, for at least 3 days a week, were randomly divided into two groups. Group A: 24 patients treated for 6 months with intramuscular (i.m.) CLO added to usual NSAIDs or analgesic drugs. The attack dose was 200 mg/day i.m. for 10 days followed by a maintenance dose of CLO i.m. 200 mg/day for 6 days after 3 and 6 months. Group B: 16 patients who continued the usual treatment with anti-inflammatory or analgesic drugs. Patients in both groups reported in a diary, day by day, the consumption of symptomatic drugs. In group A, the consumption of anti-inflammatory or analgesic drugs (p < 0.0001), pain (p < 0.0001), number of tender joints (p = 0.0097), number of swollen joints (p = 0.0251), Dreiser score (p = 0.0119), and patient's and physician's global assessment of disease activity significantly decreased (both p < 0.001). At 6 months, serum COMP also significantly decreased (p < 0.0029). Strength of right (p = 0.0465) and left hand (+38%, p = ns) significantly increased. In group B, there was no significant change in all parameters considered. Intramuscular CLO in EOA of the hand is effective and safe on pain with a significant reduction in the consumption of anti-inflammatory or analgesic drugs, increasing the functionality of the hands. Serum COMP reduction suggests that CLO could play a role as a disease-modifying drug (EudraCT number 2013-000832-85).