MAUI, HAWAII – An ongoing proof-of-concept study in the United Kingdom uses T-cell subset analysis to identify those patients with early rheumatoid arthritis who are unlikely to experience remission with methotrexate alone and therefore warrant more potent first-line therapy with a tumor necrosis factor (TNF) inhibitor in combination with methotrexate, Paul Emery, MD, said at the 2019 Rheumatology Winter Clinical Symposium.
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Dr. Paul Emery
“When we get the readout from this study, if we get the results we expect, we could actually put it to the National Health Service that it would be cost saving to use biologics as first-line therapy in a proportion, which will be about 40% of patients. But we won’t necessarily need to use them for a year, and we’ll get a 70%-plus remission rate, which I think is the sort of level we should be asking for in our patients,” according to Dr. Emery, professor of rheumatology and director of the University of Leeds (England) Musculoskeletal Biomedical Research Center.
This proof-of-concept study capitalizes on earlier work by Dr. Emery and coinvestigators, who showed in 70 patients with early rheumatoid arthritis given methotrexate as their first-ever disease-modifying antirheumatic drug (DMARD) that those with a normal pretreatment frequency of naive CD4+ T cells had an 83% remission rate at 6 months as defined by a Disease Activity Score in 28 joints (DAS28) of less than 2.6. In contrast, only 21% of those with a reduced naive CD4+ T-cell frequency experienced remission when compared with healthy controls. In an analysis adjusted for age and the presence of anti–citrullinated protein antibodies (ACPA), a normal baseline naive CD4+ T-cell frequency was associated with a 5.9-fold increased likelihood of remission on methotrexate (Ann Rheum Dis. 2014 Nov;73[11]:2047-53).
In the new proof-of-concept study, DMARD-naive, ACPA-positive patients with early RA undergo T-cell subset quantification by flow cytometry. Thirty patients with a normal test result are assigned to methotrexate with treat-to-target dose escalation. Based upon the investigators’ earlier work, it’s anticipated that about 80% of these patients will be in remission at 6 months.
Sixty patients with an abnormal baseline T-cell test result are being randomized to methotrexate plus either placebo or biosimilar etanercept. Again based upon the earlier study, the expected remission rate at 6 months in the methotrexate-plus-placebo group is about 20%. In contrast, the anticipated remission rate in the patients on an anti-TNF biologic plus methotrexate as first-line therapy is about 70% on the basis of the results of previous clinical trials, including PRIZE (N Engl J Med. 2014 Nov 6;371[19]:1781-92) and COMET (Ann Rheum Dis. 2012 Jun;71[6]:989-92).
Meanwhile, the price tag for biosimilar TNF inhibitors in the United Kingdom has come down to the point that routine across-the-board use of biologics as first-line therapy is arguably cost effective, a situation Dr. Emery described as hitherto “the unthinkable.”
The cost of biosimilar adalimumab in the coming year will be less than $3,000 annually in the U.K. health care system. So if 100 patients with early RA and no contraindication to biologic therapy are placed on biosimilar adalimumab and methotrexate for 1 year, the total cost for the biologic in this cohort will be less than $300,000, and roughly 70 of the 100 patients will have achieved remission. This approach makes much more sense than current standard practice, which is to reserve biologics as second-line therapy for patients who have failed to achieve remission on nonbiologic DMARDs, thereby allowing their joint damage to advance in the interim to the point that they need to stay on biologic therapy for decades, the rheumatologist argued.
“Once one accepts that remission has become the aim of therapy, then the facts, I think, speak for themselves: There’s absolutely no doubt that the rate of remission is best with the first DMARD. So if our aim is remission, we should use that one opportunity with the best agent first, because we’re not going to get the same response later,” Dr. Emery said.
Also, “there’s no doubt” that the dose of biologics can be halved with no loss of efficacy in patients who achieve remission on full-dose therapy, as previously demonstrated in PRIZE and other trials. This strategy further reduces the overall cost of biologic therapy, he added.
Dr. Emery, who recently received the Order of the British Empire from Queen Elizabeth personally in recognition of his career achievements in rheumatology, reported having no financial conflicts of interest regarding his presentation.