Safety of biologic/methotrexate combination therapy vs biologic monotherapy in psoriasis

In moderate-to-severe cases of psoriasis, combinations of biologic drugs and conventional systemic drugs (e.g., methotrexate) are often prescribed.¹ However, there is a lack of safety data available for these combinations.¹

This study by Lluch-Galcerá et al.,¹ published in British Journal of Dermatology, aimed to assess whether using certain combinations of biologic drugs with methotrexate increased the incidence of adverse events (AEs), compared with biologic monotherapy. The study used data from the BIOBADADERM registry, which focuses on studying drug safety.¹

Study design and patient population¹

• Of the 4,486 patients in the BIOBADADERM registry (2008–2021), this study analyzed 2,829 patients, who underwent 5,441 treatment cycles (monotherapy [90.5%], combination [9.5%]). Overall, this equated to 12,853 patient-years.
• Across the treatment groups, most patients were male, had a diagnosis of plaque psoriasis, and had prior biologic treatments.
• The primary outcome was the adjusted incidence rate ratios for total AEs, serious AEs (SAEs), and AEs by system organ class for combination vs monotherapy.
• Biologics investigated in this study were:

• • Tumor necrosis factor (TNF) inhibitors (etanercept, infliximab, or adalimumab and their biosimilars);
  • Interleukin-23 inhibitors (ustekinumab, tildrakizumab, guselkumab, or risankizumab); and
  • IL-17 inhibitors (secukinumab, ixekizumab, and brodalumab).

Key findings¹

• A total of 7,230 AEs were reported, with the majority in patients receiving biologic monotherapy (the predominant treatment group) (Figure 1A).
  • Overall, patients on combined therapy had a higher incidence of AEs, but this was not significant. The incidence of SAEs was similar between the groups (Figure 1B).
  • A significant increase in gastrointestinal AEs was seen in patients receiving TNF inhibitors plus methotrexate compared with TNF inhibitor therapy alone (adjusted incidence rate ratio 2.50; 95% confidence interval, 1.57–3.98). This significant difference was not seen for any other combinations.

AE, adverse event; IL, interleukin; MTX, methotrexate; SAE, serious adverse event; TNF, tumor necrosis factor.
*Data from Lluch-Galcerá, et al.¹

Key learnings

Generally, combining biologic therapy with methotrexate did not significantly increase the risk of AEs or SAEs. The safety profile of biologic/methotrexate combinations should not be a limitation when prescribing for patients who have had an inadequate response to monotherapy or in the case of certain comorbidities, including psoriatic arthritis. This study may be limited due to the low statistical power from the low number of AEs reported.