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Conducting clinical trials for osteoarthritis: ORS
Medical expert of the article
Last reviewed: 23.04.2024
The recommendations of the Osteoarthritis Research Society (ORS) are based on the division of anti-arthritis drugs proposed by the WHO and ILAR into two groups: symptomatic (fast and slow) and modifying the cartilage structure. Obviously, demonstrating the benefits of these drugs will largely depend on the design of the study and the selected effectiveness criteria. In this case, the design of the study will depend on the mechanism of action of the drug substance and the expected result.
When planning a study, the following factors should be considered:
- pharmacodynamics of the drug,
- time from the beginning of the drug until the effect,
- the duration of the preservation of the effect obtained as a result of treatment, after drug withdrawal,
- the route of application of the drug (topically, orally, parenterally, etc.)
- frequency and severity of side effects,
- influence on pain syndrome,
- influence on inflammation,
- influence on other symptoms of the disease.
Most members of the committee who participated in the study of this issue were inclined to think that with respect to the design of clinical studies of osteoarthritis, there is no need to separate symptomatic preparations into two subclasses - fast and slow. The first include non-narcotic analgesics and NSAIDs, to the second - drugs for which the symptomatic effect is not the main - hyaluronic acid, chondroitin sulfate, glucosamine, diacerein. Thus, in these recommendations, the term "symptomatic drugs" is used for both fast-acting and slow-acting symptomatic drugs. When drawing up the study protocol, it should be borne in mind that the symptomatic preparation may have the properties to modify the cartilage structure (favorable and unfavorable).
Regardless of the effect on the symptoms of the disease, the drug may have an effect on the structure or function of the affected joint. The protocol for the study of the effectiveness of drugs, probably modifying the pathological process in osteoarthritis, should include criteria reflecting the change in the structure of the joint. Such drugs can:
- prevent the development of osteoarthritis and / or
- prevent, slow the progression of existing osteoarthritis or stabilize the patient's condition.
A drug that has a pathogenetic effect need not necessarily influence the symptoms of osteoarthritis. The symptomatic effect of such a drug should be expected only after a long period of treatment. In order to study the effectiveness of the drug that modifies the structure of cartilage, it is not necessary to include the study of its symptomatic effect.
Preparations potentially capable of modifying the cartilage structure are called "chondroprotectors", "Disease Modifying OA drugs", "anatomical modifying drugs", "morphology modifying agents", etc. Unfortunately, there is no consensus on the term that most fully reflects the effect of these agents. ORS uses the term "structure-modifying drugs" in its recommendations and notes that by now no properties have been proven for any agent to modify the cartilage structure in vivo in humans.
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