No differences found in malignancies rates between patients with rheumatoid arthritis treated with tocilizumab versus TNF inhibitors

The results of a study presented at the Annual European Congress of Rheumatology (EULAR 2018) examined rates of malignancy in patients with rheumatoid arthritis (RA), excluding non-melanoma skin cancer (NMSC), and found no difference between those newly treated with tocilizumab versus TNF inhibitors (TNFi) (Kim et al., 2018).

RA is a chronic inflammatory disease that causes pain, swelling and stiffness in a person’s joints, particularly the hands, feet and wrists. Prevalence increases with age, but it is not uncommon for young adults, adolescents and even children to have the condition.

Patients with RA have been shown to be at increased risk of developing certain malignancies, thought to be due to the immune dysregulation and/or chronic inflammation in RA. Recently, biologic  disease modifying anti-rheumatic drugs (bDMARDs) have become available which aim to treat the underlying cause of disease, as opposed to solely relieving symptoms. There are some concerns as their target-specific inhibition of the immune system may cause other health issues. Data on the influence of bDMARDs on malignancy has been conflicting, however (Cho et al., 2017).

“The risk of malignancy among patients with RA has been of ongoing interest,” said Professor Robert Landewé, Chairperson of the Scientific Programme Committee at EULAR. “With more biologic treatment options available and earlier initiation of therapy, it is important to understand the risk of malignancies in patients with RA.”

This study examined the rate of incident malignancy, excluding NMSC, in patients with RA who were newly treated with either tocilizumab or TNFi (Kim et al., 2018).

“Our study is one of a few to investigate head-to-head comparisons of malignancy risk between different types of biologics in RA,” said Seoyoung Kim, study author and Associate Professor of Medicine at Brigham and Women’s Hospital and Harvard Medical School. “This study found no difference in the risk of malignancy, excluding NMSC, in patients with RA who newly switched to tocilizumab versus TNFi from a different TNFi, abatacept or tofacitinib.”

The study included adult patients with RA who had newly started on tocilizumab or a TNFi after failing on abatacept, tofacitinib or another TNFi. Investigators used three healthcare claims databases (Medicare, IMS ParMetrics Plus and Truven MarketScan) from 2010-2015 to identify 10,393 tocilizumab initiators who were propensity score matched (1:3 variable ratio) to 26,357 TNFi initiators. This is a statistical matching technique that controls for over 60 potential baseline confounding variables. Individuals were followed up until treatment discontinuation, outcome occurrence, disenrollment, death or the end of the study period (Kim et al., 2018).

The primary outcome was an incidence of malignancy (excluding NMSC) which were identified based on two diagnosis codes within two months. The incidence of malignancy per 100 person-years ranged from 0.83 to 2.32 in tocilizumab patients, and from 0.96 to 2.15 in TNFi patients between the different databases. Statistical analysis revealed no significant differences between the groups. In addition, there were no significant differences in the incidence of the ten most frequently occurring cancers and leukaemia or human papilloma virus-related cancer which were analysed as individual secondary endpoints (Kim et al., 2018).

The patents for tocilizumab expired in 2015 and 2017 in the US and EU respectively opening the door to biosimilar medicines. For example, there is one tocilizumab biosimilar in development primarily for the treatment of Castleman’s disease (GaBi, 2016). Learn more about the potential of biosimilars in rheumatology by reading our recent article that discusses the benefits they could have over biologics and the challenges they face.

References

Cho SK, Lee J, Han M, et al. The risk of malignancy and its incidence in early rheumatoid arthritis patients treated with biologic DMARDs. Arthritis Res Ther. 2017;19(1):277.

GaBi. Biosimilars of Tocilizumab. 2016. Available from: http://www.gabionline.net/Biosimilars/General/Biosimilars-of-tocilizumab (accessed 15th June 2018).

Kim SC, Pawar A, Desai RJ, et al. No difference in the risk of malignancy in tocilizumab versus TNF inhibitor initiators in patients with rheumatoid arthritis: A multi-database cohort study. EULAR 2018; Amsterdam: Abstract OP0002.