Clinical trial of microcrystalline hydroxyapatite compound ('Ossopan') in the prevention of osteoporosis due to corticosteroid therapy

Abstract

A controlled clinical trial was carried out in 40 patients at risk of osteoporosis because of long-term treatment with prednisolone (5 to 20 mg/day) to determine the efficacy and tolerance of microcrystalline hydroxyapatite compound (MCHC) when used to prevent the appearance or progression of osteoporosis: 32 patients were treated with 6 to 8 g MCHC for 12 months and 8 served as an untreated control group. The two groups were well matched as regards age, sex and underlying disease; 37 patients (29 MCHC, 8 control) successfully completed the trial. The majority (68%) of the patients had back pain prior to the trial, the severity of which was graded at 3-monthly intervals. In the MCHC-treated group, there was a dramatic and significant (p<0. 001) reduction in pain during the trial, almost to the point of its disappearance. Of 19 patients with initial back pain only 2 still reported any pain at all after 12-months' MCHC treatment. In the control group, back pain severity increased during the trial in 3 patients and was unchanged in the fourth. Neither MCHC-treated nor control group patients showed any significant change in standing or stem height during the 12-months' trial period. Both mean cortical thickness and mean metacarpal index figures showed small, insignificant decreases during 12-months' MCHC treatment but much more marked decreases in the control group which, despite the small number of patients, came close to being statistically significant. Fifteen (52%) of the MCHC-treated patients expressed dissatisfaction with the palatability of the powder formulation of MCHC and 9 (31%) were changed to an equivalent dose of tablets; all then completed the trial successfully. There were no reports of drug-related side-effects in the MCHC-treated putients. Laboratory tests of renal and hepatic function revealed no signs of toxicity during MCHC therapy. There was a significant (p<0.01) increase in plasma calcium levels associated with a similar increase in phosphate levels during MCHC treatment. Calcium × phosphate product therefore increased, producing the necessary biochemical environment for bone remineralization. The results indicate that, with MCHC therapy, dramatic reductions in symptoms (skeletal pain) in patients developing osteoporosis due to long-term corticosteroid treatment are associated with favourable biochemical and bone changes, which could probably be expected to progress further during longer-term MCHC therapy.