Biosimilars, originators discontinued at similar rates for inefficacy, adverse events
Click Here to Manage Email Alerts
Key takeaways:
- TNF inhibitors and their biosimilars showed no significant differences in risk for discontinuation due to inefficacy or adverse events.
- Originators were discontinued more often than biosimilars overall.
Subcutaneous TNF inhibitors and their biosimilars are discontinued due to inefficacy and adverse events at similar rates in patients with rheumatic diseases, according to data from Spain published in The Journal of Rheumatology.
“Although the survival of the different [biologic disease-modifying antirheumatic drugs (DMARDs)] in Spanish patients with rheumatic diseases in clinical practice has been recently analyzed, we do not know if there are differences in treatment survival depending on whether patients receive an originator or a biosimilar molecule,” María Paz Martínez-Vidal, MD, PhD, of the Hospital Universitario San Juan de Alicante, in Spain, and colleagues wrote. “Lower retention rates of biosimilars in a real-world clinical setting might raise concerns about safety issues or suggest that biosimilars are less effective than originators.”
To compare the discontinuation of originator TNF inhibitors vs. their biosimilars among patients with rheumatic diseases, Martínez-Vidal and colleagues analyzed data from BIOBADASER, a Spanish multicenter prospective registry. The analysis included 4,162 patients who received either originator or biosimilar adalimumab (Humira, AbbVie) or etanercept (Enbrel, Amgen). There were 4,723 treatment courses in total — 2,991 of adalimumab and 1,732 with etanercept — 15.29% of which were with originator molecules and 84.71% were with biosimilars.
The researchers used Kaplan-Meier curves to estimate the adherence to treatment with etanercept, adalimumab or their biosimilar molecules. Cox regression models identified factors associated with differences in retention rates.
According to the researchers, originators were discontinued more often than biosimilars — 53.32% vs. 33.37%, respectively — and the overall risk for discontinuation was lower for biosimilars (adjusted HR = 0.84; 95% CI, 0.75-0.95).
However, the analysis found no statistically significant differences between the risks for discontinuation due to inefficacy or adverse events with originators vs. biosimilars.
Factors associated with discontinuation included female sex (P = .001), obesity (P = .03), and the therapy being second-line treatment (P = .03), or third-line or later (P < .001). Greater retention was linked with disease duration (P < .001) and concomitant methotrexate (P = .001), but not other conventional synthetic DMARDs. The use of concomitant methotrexate “should be considered when appropriate,” the researchers concluded.
“In this Spanish multicenter, prospective, observational registry of patients with rheumatic diseases, there was no difference in long-term survival due to inefficacy or [adverse events] between subcutaneous biosimilar [TNF inhibitors] and the originator [TNF-inhibitor] molecules,” Martínez-Vidal and colleagues wrote. “In real-world practice, this can be reassuring when deciding to start a biosimilar. Concomitant [methotrexate] was associated with higher retention rate, and its use should be considered when appropriate.”
Collapse
Click Here to Manage Email Alerts