Background and importance Desensitisation protocols allow the induction of tolerance to a drug causing hypersensitivity, achieving adequate administration of the treatment and avoiding the loss of a therapeutic alternative.

Aim and objectives To describe a desensitisation protocol for subcutaneous adalimumab.

Material and methods A 51-year-old women diagnosed with arthropathic psoriasis (AP) failed multiple different lines of treatment (apremilast, secukinumab, adalimumab, etanercept, tofacitinib) due to allergic reactions. Given the limited therapeutic alternatives, adalimumab was restarted, presenting again a hypersensitivity episode represented as a maculopapular eczematous reaction. The allergologist proposed a desensitisation regimen to adalimumab to induce tolerance to the drug.

Results A desensitisation protocol (DP) was designed to progressively reach the therapeutic dose of 40 mg. The protocol consisted of six doses of increasing concentration administered one every 15 days. Doses were prepared from a 40 mg/0.8 mL vial of adalimumab. Dilutions were made with sterile water to prepare five solutions of increasing concentration: 0.5 mg/mL, 1.25 mg/mL, 5 mg/mL, 10 mg/mL and 20 mg/mL. The first three solutions (0.5 mg/mL, 1.25 mg/mL, 5 mg/mL) were obtained by taking 0.5 mL from the vial and diluting with sterile water to a dilution of 5 mg/mL. From this concentration the required doses were obtained. The fourth and fifth solutions (10 mg/mL, 20 mg/mL) were obtained by taking 0.8 mL from the vial and diluting with sterile water to the final concentration. For the sixth dose (40 mg/0.8 mL) the entire vial was used and no dilution was required.

The DP was administered by the allergologist at the hospital. Premedication consisted of antihistamines and corticoids administered on the same day as the PD. After each administration, the observation time for adverse reactions was at least 1 hour. During the administration cycles the patient had no adverse reactions. After the six doses of DP, the patient continued with the usual dose of adalimumab 40 mg/0.8 mL for 6 months, administered at home. No adverse reactions were observed. She showed clinical and analytical improvement, with the prospect of continuing the treatment.

Conclusion and relevance DP for adalimumab was successful. The use of DP allowed an adequate and safe administration of adalimumab, avoiding the loss of a therapeutic line in a patient diagnosed with AP with very few treatment options.

Conflict of interest No conflict of interest