Low-dose IL-2 promising in bullous pemphigoid treatment

Key takeaways:

• Patients with bullous pemphigoid treated with IL-2 had fewer days to disease control vs. those on corticosteroids alone.
• In the first 2 weeks of IL-2 treatment, a significant expansion of Treg cells was shown.

A low dose of interleukin-2 therapy showed positive results in the treatment of bullous pemphigoid with an early onset of response, according to a study.

“The incidence of [bullous pemphigoid (BP)] is increasing, especially in the age group of 70 and above, and the bullae and pruritus seriously affect quality of life,” Ruzeng Xue, MD, of the First School of Clinical Medicine, Southern Medical University in Guangzhou, China, and colleagues wrote. “Current therapy focuses on immunosuppressants to inhibit the production of antibodies.”

In earlier studies, regulatory T cells (Tregs) in peripheral blood and skin lesions of patients with BP have been lower than in the general population. IL-2 has also previously shown benefits in regulating and activating human Tregs.

This perspective, comparator-controlled clinical trial evaluated if a low dose of IL-2 (Recombinant Human Interleukin-2 Injection, Beijing Sihuan Biopharmaceutical Co.) was efficacious in the treatment of BP.

The study included 20 patients assigned to a control group, in which patients received a daily initial dose of 0.5 mg/kg of corticosteroids for moderate disease or 1 mg/kg for severe disease, and 23 patients in the treatment group who received the same corticosteroid therapy in addition to low-dose IL-2 every other day.

Final analysis included 23 patients in the study group and 17 in the control group.

Disease control was achieved in 7.6 ± 3 days in the treatment group, compared with 10.43 ± 3.06 days in the control group (P = .008).

After 1 week of treatment, 60.9% of patients achieved disease control compared with 17.6% of those in the control group (P = .01), and a greater reduction in Bullous Pemphigoid Disease Area Index scores was recorded in the IL-2 treatment group (P = .003).

Statistical significance, however, did not continue at later time points.

Adverse events included redness and swelling at injection sites for three patients, but no serious adverse events were reported.

Cytometry analysis showed Treg cells expansion from 5.03% at baseline to 10.14% at week 1 (P = .0069) and 6.65% at week 2 (P = .019) in the treatment group, which was a significant difference compared with the control group. At week 4, the difference was not significant.

The treatment group also needed a smaller dose of corticosteroids to reach disease control.

“Our results suggest that low-dose IL-2 therapy is promising for its early onset of response, especially in the first 2 weeks,” the authors wrote. “We speculate that the rapid increase of Treg cells in the first week was beneficial for disease control and early steroids reduction.”