An expert task force convened by the Osteoarthritis Research Society International (OARSI) has started the process of consolidating classification criteria for early-stage knee osteoarthritis (OA).
“Early-stage knee OA classification criteria, we believe are critically required,” Gillian Hawker, MD, MSc, said at the OARSI 2022 World Congress.
Dr. Gillian Hawker
Dr. Hawker, who is the chair of the Task Force Steering Committee, noted that classification criteria are needed for several reasons, such as “to advance OA therapeutics and [the] earlier identification of people with knee OA who can benefit from existing treatments.”
Moreover, they are needed so that people with knee OA can “be poised and ready to receive available therapies once we develop them,” said Dr. Hawker, professor of medicine at the University of Toronto and a senior clinician-scientist in the Women’s College Research Institute at Women’s College Hospital in Toronto.
Reasoning for looking at early OA
“Osteoarthritis is a very serious disease with a growing population burden,” Dr. Hawker reminded delegates at the congress. Yet despite “amazing advances” in the understanding of the pathophysiology of disease and several potential druggable targets being identified, “we still have no safe and effective interventions to prevent or slow the progression of the disease.”
“Why have all the DMOADs [disease-modifying osteoarthritis drugs] failed?” she questioned.
One hypothesis is that it’s down to the heterogeneity of OA. “We’ve been plugging people with different kinds or phenotypes of OA into the same clinical trials, and we need to better match OA phenotypes with appropriate treatment,” Dr. Hawker said.
Also, “structural changes on imaging, and the symptoms that characterize the disease of function, pain, stiffness, etc., are not super well correlated. It may be that any attempts at structure modification alone won’t adequately improve clinical symptoms.”
Perhaps most importantly, however, “we’re treating people way too late in the course of their disease,” Dr. Hawker said. “When we keep putting people with Kellgren and Lawrence [grade] 2 or 3 into clinical trials, it may be that we there’s nothing that we’re going to be able to do that’s really going to make a difference.”
Why just knee OA?
The reason for looking at early-stage OA specifically is that current knee OA classification criteria were developed nearly 40 years ago and were looking at a later stage of disease, mainly differentiating OA from other types of inflammatory arthritis, notably rheumatoid arthritis (RA).
The aim of the OARSI Early OA Task Force is thus to develop, refine, and validate classification criteria that will not only help identify people with early-stage OA who can then be entered into clinical trials of new therapies but also define a population that can be used in preclinical and prognostic work.
“The task force decided to start with early-stage knee OA due to the highest burden and the focus of most clinical trials,” steering committee member Martin Englund, MD, PhD, observed during the discussion.
Dr. Martin Englund
“When we see how that goes, we may consider early hip OA,” said Dr. Englund, of Lund University and Skåne University Hospital in Sweden.
Dr. Hawker added that the task force felt that lumping hip and knee OA together would complicate matters because they thought that the classification criteria will likely look very different from each other.
“But the good news is we think that if we can identify early knee OA, we will likely also identify people with at least hand OA,” she said.