Anti-Drug Antibodies, Drug Levels, Interleukin-6 and Soluble TNF Receptors in Rheumatoid Arthritis Patients during the First 6 Months of Treatment with Adalimumab or Infliximab: A Descriptive Cohort Study.

OBJECTIVES: With the present study we wanted to explore the impact of treatment with a tumor necrosis factor-α -inhibitor (TNFi) on levels of soluble biomarkers in rheumatoid arthritis (RA) patients and to identify predictors of impaired drug levels and development of anti-TNFi antibodies (anti-TNFi Abs). METHODS: Blood samples from 26 patients with established RA were taken at baseline and following 6 months of treatment with adalimumab or infliximab. Samples were analyzed for levels of TNFi, interleukin (IL)-6, and soluble TNF-receptors 1 and -2 (sTNF-R1 and -2) and for presence of anti-TNFi Abs. Clinical and demographic data were recorded as well. RESULTS: During the initial 6 months treatment, DAS28(CRP) (Disease activity score in 28 joints using C-reactive protein) and levels of IL-6 and sTNF-R2 decreased significantly in patients without anti-TNFi Abs and in patients retaining detectable drug levels. The levels of other tested cytokines (TNF-α, TNF-ß, IL-1ra, IL-1b, IL-8, IL-10, IL-12(p70), IL-13, IL-17A, IL-17F, and IL-33) were generally below detection limits. Higher baseline levels of IL-6 associated with undetectable levels of TNFi at follow-up. Anti-TNFi Abs were associated with decreased drug levels, but no predictors for anti-TNFi Ab development could be found. CONCLUSION: The effect of treatment with TNFi on RA disease activity depends on levels of active drug, and by presence of anti-TNFi Abs. In patients who retain detectable drug levels, and in the absence of anti-TNFi Abs, clinical outcome is improved during treatment, and circulating levels of IL-6 and sTNF-R2 decrease. Baseline levels of IL-6 may predict depletion of TNFi and may identify patients at risk of treatment failure.

Efficacy of treatment intensification with adalimumab, etanercept and infliximab in rheumatoid arthritis: a systematic review of cohort studies with focus on dose.

OBJECTIVES: To summarize the empirical evidence regarding the effect of treatment intensification on clinical outcomes in patients with rheumatoid arthritis treated with one of the TNF-α-inhibitors, adalimumab, etanercept or infliximab. METHODS: A systematic search of the bibliographic databases Embase, Medline, Web of Science and Cochrane Central identifying articles concerning treatment with adalimumab, etanercept or infliximab in adult patients with rheumatoid arthritis exposed to dose increase or shortening of dosing intervals was performed. Longitudinal cohorts, both clinical trials and observational studies, were included. ACR and EULAR response criteria and DAS28 were the preferred outcome measures. RESULTS: Out of 1135 records, eleven studies were included in the final evidence synthesis. One article concerned all the three TNF-α-inhibitors, eight used infliximab, one adalimumab and one etanercept. According to GRADE, evidence was weakened in particular by the lack of control groups, and for treatment intensification with adalimumab and etanercept, no conclusions could be drawn. With infliximab, two trials of high quality revealed contradictory results, but six studies described an improved clinical outcome following intensified treatment strategies. Some studies (2/2) also indicated that for infliximab, frequency increase was superior to dose increase. CONCLUSIONS: Available studies indicate that intensifying treatment with infliximab in rheumatoid arthritis patients, preferably by increasing the frequency of drug administration, may lead to improved clinical outcome in some patients, but the evidence is weak. There is an urgent need for prospectively designed cohort studies to be able to draw a final conclusion.

Severe lactic acidosis in a patient with metastatic prostate cancer.

Lactic acidosis (LA) due to malignancy was first reported in patients with acute leukemia. Since then, several malignancies have been reported to be associated with LA. The pathophysiology of cancer-related LA is multifactorial and still poorly understood. In general, chemotherapy is the only effective mean of correcting malignancy-related LA by cytoreduction of the tumor cells while at the same time decreasing malignant liver involvement leading to improved clearance of lactic acid. LA is rare in patients with malignancies and is usually associated with high mortality because of advanced disease process and high tumor burden. Increased awareness of this complication in certain malignancies is important because early initiation of chemotherapy may decrease LA and perhaps prolong survival. To our knowledge, this is the first case of otherwise unexplained severe LA in a patient with chemotherapy-refractory metastatic prostate cancer.