Intravenous, subcutaneous forms of tocilizumab similarly effective in RA patients
medwireNews: Real-world study results suggest that the subcutaneous and intravenous forms of tocilizumab are associated with similar effectiveness among patients with rheumatoid arthritis (RA).
“[C]onsidering the costs of the intravenous route”, these findings suggest that “subcutaneous tocilizumab should be the preferred mode of administration” when possible, say Kim Lauper (Geneva University Hospitals, Switzerland) and fellow researchers.
The team used the TOCERRA collaboration of eight European registries to compare the effectiveness of the two forms of tocilizumab in 3448 RA patients who started treatment with the interleukin-6 inhibitor between 2009 and 2018.
Unadjusted duration of drug retention – defined as the time from starting tocilizumab until 1 month after the time of discontinuation – was longer for the 2414 patients taking intravenous tocilizumab compared with the 1034 patients taking the subcutaneous form, at a median of 3.52 versus 2.12 years.
However, the probability of discontinuing treatment was similar among the two groups in an analysis stratified by country and year of treatment initiation, and adjusted for factors including age, sex, smoking, BMI, disease duration, and inflammation.
Lauper and colleagues say that the difference in the unadjusted time on treatment between the two formulations of tocilizumab “was mainly associated [with] the treatment year of initiation”, noting that intravenous tocilizumab was approved in 2009, followed by the subcutaneous form in 2014. They add that a “progressive increase” in the use of subcutaneous tocilizumab occurred over the study period, with more patients initiating the subcutaneous compared with the intravenous formulation from 2015 onwards.
The researchers observed similar evolution in disease activity among patients treated with subcutaneous and intravenous tocilizumab. Median Clinical Disease Activity Index (CDAI) scores decreased from 17 points at baseline to approximately 10 points at 2 years in both groups, and average adjusted CDAI scores and their evolution did not significantly differ between groups.
And in an analysis of the patients who were still undergoing treatment at the 1-year follow-up, a comparable 13.9% of 1525 patients receiving intravenous tocilizumab and 15.3% of the 524 taking the subcutaneous formulation were in remission according to a CDAI score of 2.8 points or lower.
The investigators also demonstrated that switching between intravenous and subcutaneous tocilizumab “did not seem to alter effectiveness”, with comparable decreases in CDAI observed over the study period among patients who did and did not switch.
“In conclusion, our study shows that [subcutaneous tocilizumab] is an adequate alternative to [intravenous tocilizumab] in RA”, write Lauper and team in RMD Open.
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