Does Rheumatoid Factor Influence Anti-TNF Responses in RA? Smolen and colleagues have published a subanalysis of the EXXELERATE study that showed while certolizumab pegol [CZP] concentrations and efficacy was unaffected by high titers of rheumatoid factor (RF), patients treated… https://t.co/Ux9gHXcGbv https://t.co/gpcuWrqVHi