Tumor necrosis factor inhibitor (TNFi) has illustrated efficacy in controlling psoriatic arthritis (PsA).1 One of the recommendations for PsA management is putting TNFi as a second-line treatment option following methotrexate (MTX), but the association between the use of TNFi in PsA and increased cancer risk has not been confirmed nor rejected until recently.2-3 The overall malignancy risk for PsA patients treated with TNFi was found not to be elevated.3 These findings were published as an abstract in the Annals of the Rheumatic Diseases.3
TNFi is categorized as a biological disease-modifying antirheumatic drug (bDMARD), which is recommended as second-line therapy when methotrexate is unable to manage PsA from the guidelines published by the European League Against Rheumatism (EULAR).2
The efficacy of TNFi in PsA patients was shown previously.1 At weeks 12-16, TNFi, including infliximab, etanercept, adalimumab and golimumab, demonstrated efficacy in American College of Rheumatology (ACR) 20, 50 and 70 response, Psoriasis Area and Severity Index (PASI) and PsA Response Criteria (PsARC).1 These TNFis also showed improvements in self-reported Health Assessment Questionnaire (HAQ) at weeks 12 and 24, while radiographic progression of the disease was slower in TNFi-treated patients when compared to placebo at months 6 and/or 12.1 Certolizumab, another TNFi, displayed sustained efficacy in patients with PsA for ACR20, 50 and 70 response and 28-joint count Disease Activity Score (DAS28) from week 24 to week 216.4
Increased cancer incidence was not observed in PsA patients treated with TNFi in a previous study.5 Although the prevalence of nonmelanoma skin cancer in PsA patients receiving TNFi was elevated, study investigators could not conclusively state an association between the increased cancer risk and the use of TNFi in PsA due to wide confidence intervals calculated for the cancer hazard ratio (Nonmelanoma skin cancer HR in PsA=2.65; 95% CI: 0.33-21.07).5
The recently published study recruited 8,053 TNFi-treated PsA patients from Sweden, Denmark, Iceland and Finland, with no cancer history prior to study initiation.3 The investigation focused on standardized comparison of primary cancer risk between PsA patients receiving TNFi therapy and the general population, and had a total follow-up observation time of 44,041 patient-years.3
Study investigators revealed that the number of observed cancers of any types in TNFi-treated PsA patients was similar to the expected number, with a standardized incidence ratio (SIR) of 1.00 (95% CI: 0.89-1.13).3 However, an increase in SIR of Hodgkin’s and non-Hodgkin’s lymphoma among PsA patients treated with TNFi when compared to the general population (SIR: 1.84; 95% CI: 1.20-2.82) was also discovered.3
Rheumatoid arthritis (RA) was found to be associated with elevated risk for lymphoma.6 Since patients with most severe PsA may have an increased risk for RA, while PsA patients with RA may also have participated in the study, the increased risk of lymphoma among PsA patients might be explained by RA.6 The authors of the study recommended further in-depth analysis of the malignant lymphoma risk to confirm whether the observed incidence increase is contributed by PsA itself or TNFi medication.3
1. Ash Z, Gaujoux-Viala C, Gossec L, et al. A systematic literature review of drug therapies for the treatment of psoriatic arthritis: current evidence and meta-analysis informing the EULAR recommendations for the management of psoriatic arthritis. Ann Rheum Dis. 2012;71(3):319-26.
2. Gossec L, Smolen JS, Ramiro S, et al. European League Against Rheumatism (EULAR) recommendations for the management of psoriatic arthritis with pharmacological therapies: 2015 update. Ann Rheum Dis. 2016;75(3):499-510.
3. Ballegaard C, Hellgren K, Cordtz R, et al. OP0005 Incidence of overall and site-specific cancers in TNF inhibitor treated patients with psoriatic arthritis: a population-based cohort study from 4 Nordic countries. Ann Rheum Dis. 2019;78:67-8.
4. Walsh JA, Gottlieb AB, Hoepken B, et al. Efficacy of certolizumab pegol with and without concomitant use of disease-modifying anti-rheumatic drugs over 4 years in psoriatic arthritis patients: results from the RAPID-PsA randomized controlled trial. Clin Rheumatol. 2018;37(12):3285-96.
5. Haynes K, Beukelman T, Curtis JR, et al. Tumor necrosis factor α inhibitor therapy and cancer risk in chronic immune-mediated diseases. Arthritis Rheum. 2013;65(1):48-58.
6. Hellgren K, Smedby KE, Backlin C, et al. Ankylosing spondylitis, psoriatic arthritis, and risk of malignant lymphoma: a cohort study based on nationwide prospectively recorded data from Sweden. Arthritis Rheumatol. 2014;66(5):1282-90.