For the other questions which the study aimed to answer, the results are encouraging. “When we were interested in the different criteria making it possible to identify the responders to treatment, we observed, according to the chosen criterion and the dose of strontium ranelate studied, a reduction in the risk of being classed as ‘progressor’ going from 23 à 44 %. Finally, if the two doses of strontium ranelate show a beneficial effect on the structural progression of arthrosis, the dose of 2 grams per day makes it possible to obtain a significant effect on pain and joint function, and all this within a six-month period”, explains Prof. Reginster. 

According to the specialist, this reduction in the number of “progressors”, associated with the improvement in the symptoms of patients suffering from knee pain, seems clinically relevant. “Indeed, the financial cost and the risk of operation associated with the insertion of prosthetics of the hip and knee following the presence of arthrosis, make them a major public health problem, principally in countries like Europe and North America where overweight and obesity are frequent. The possibility of reducing the proportion of patients presenting severe arthrosis of lower the members needing surgery is an interesting prospect for the long-term management of arthrosis”. Finally, the percentage of patients whose cartilage loss is higher than 0.5 mm and among whom no improvement of their symptoms was noted, went from 12% to 6.5 % at the end of the study.

An astonishing discovery?

The researchers would be wrong to deny themselves satisfaction given the conclusions of this study. However, it must be said that the results did not entirely surprise them. “We could expect the results from the moment we understood that strontium ranelate very likely acted with a mixed effect: its impact concerns both the synthesis of the cartilaginous matrix and the mechanical properties of the subchondral bone. Preclinical studies had shown that relatively small doses of strontium ranelate made it possible to simulate the components of the cartilaginous matrix. In addition, in all the studies assessing the effect of strontium ranelate on post-menopausal osteoporosis, it appeared that the dose of 2 grams per day (the one marketed for the treatment of osteoporosis) was necessary to obtain a beneficial effect in relation to these structures”, recalls Prof.  Reginster.
 
A last important point: the results of this study were presented at the same time as the publication, by the European Medicines Agency (EMA), of the reassessment of strontium ranelate, requested by AFFSAPS (the French Agency For Sanitary Safety of Health products). “The EMA concluded that the rapport benefit –risk of strontium ranelate remained highly positive. This medicine is however counter indicative in patients with deep vein thrombosis, a history of this disease or who are bedridden for a long period,” explains Prof. Reginster

Currently, two new studies are planned for this product. One of these concentrates on the confirmation of the multicenter study on a specifically Asian group of people. The other ensures the monitoring, over a five-year period, of the cohort dealt with in this study, in order to better know the percentage of patients who will actually need to resort to surgery in order to replace their joint with a prosthetic. “For many years, the treatment of arthrosis was concentrated on the cartilage, without taking the neighboring structures into account. Here we have a comprehensive treatment for the disease which makes it so interesting”, explains Prof. Reginster. If the patients suffering from arthrosis are not champing at the bit, it is only because they need to spare their joints…