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Rituximab versus tocilizumab in rheumatoid arthritis: synovial biopsy-based biomarker analysis of the phase 4 R4RA
Felice Rivellese1,2, Anna E A Surace1,2, Katriona Goldmann1,2
1Centre for Experimental Medicine and Rheumatology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
Abstract:
Patients with rheumatoid arthritis (RA) receive highly targeted biologic therapies without previous knowledge of target expression levels in the diseased tissue. Approximately 40% of patients do not respond to individual biologic therapies and 5-20% are refractory to all. In a biopsy-based, precision-medicine, randomized clinical trial in RA (R4RA; n = 164), patients with low/absent synovial B cell molecular signature had a lower response to rituximab (anti-CD20 monoclonal antibody) compared with that to tocilizumab (anti-IL6R monoclonal antibody) although the exact mechanisms of response/nonresponse remain to be established. Here, in-depth histological/molecular analyses of R4RA synovial biopsies identify humoral immune response gene signatures associated with response to rituximab and tocilizumab, and a stromal/fibroblast signature in patients refractory to all medications. Post-treatment changes in synovial gene expression and cell infiltration highlighted divergent effects of rituximab and tocilizumab relating to differing response/nonresponse mechanisms. Using ten-by-tenfold nested cross-validation, we developed machine learning algorithms predictive of response to rituximab (area under the curve (AUC) = 0.74), tocilizumab (AUC = 0.68) and, notably, multidrug resistance (AUC = 0.69). This study supports the notion that disease endotypes, driven by diverse molecular pathology pathways in the diseased tissue, determine diverse clinical and treatment-response phenotypes. It also highlights the importance of integration of molecular pathology signatures into clinical algorithms to optimize the future use of existing medications and inform the development of new drugs for refractory patients.
Insights
Biomolecular signatures in rheumatoid arthritis (RA) tissue predict response to biologic therapies like rituximab and tocilizumab. Machine learning models can identify patients likely to respond or be resistant to treatment, improving precision medicine for RA.
Area of Science:
- Rheumatology
- Immunology
- Precision Medicine
- Molecular Pathology
Background:
- Rheumatoid arthritis (RA) patients often receive targeted biologic therapies without prior knowledge of tissue-specific target expression.
- A significant portion of RA patients (approx. 40%) exhibit insufficient response to individual biologic therapies, with 5-20% being refractory to all available treatments.
Purpose of the Study:
- To investigate synovial biopsy molecular signatures for predicting treatment response in RA patients undergoing biologic therapy.
- To identify distinct molecular pathways associated with response or resistance to rituximab and tocilizumab.
- To develop machine learning algorithms for predicting treatment response and multidrug resistance in RA.
Main Methods:
- In-depth histological and molecular analyses of synovial biopsies from the R4RA randomized clinical trial (n=164).
- Identification of gene expression signatures related to humoral immune response and stromal/fibroblast activity.
- Development and validation of machine learning algorithms using nested cross-validation to predict treatment response.
Main Results:
- Humoral immune response gene signatures correlated with response to rituximab and tocilizumab.
- A distinct stromal/fibroblast signature was identified in patients refractory to all medications.
- Machine learning models achieved significant predictive accuracy for rituximab (AUC=0.74), tocilizumab (AUC=0.68), and multidrug resistance (AUC=0.69).
Conclusions:
- Disease endotypes, driven by molecular pathology, dictate diverse clinical and treatment-response phenotypes in RA.
- Integrating molecular pathology signatures into clinical algorithms can optimize current RA treatments and guide the development of novel therapies for refractory cases.
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