Background and Importance Current treatment for Monkeypox’s disease (MPXV) is mainly symptomatic. However, in immunocompromised patients, hospitalisation and treatment with antiviral drugs may be necessary. With the recent outbreak of MPXV, new strategies have been proposed.

Aim and Objectives The aim of the study was to describe our clinical experience with tecovirimat and cidofovir in the treatment of MPXV in a patient whose CD4+ lymphocyte level is less than 50 cells/ml.

Material and Methods The effectiveness of tecovirimat-cidofovir was assessed by the evolution of the rash from macule to crusts that dry up and fall off.

Results The patient was a 35-year-old man diagnosed with MPXV who presented skin lesions in the perineal area, extremities, face, trunk and back and severe proctitis. At admission, the patient was diagnosed with HIV (severely immunosuppressed with CD4+ lymphocyte levels of <40 cells/ml), so he was started on antiretroviral treatment (BIC/TAF/TDF). Sexually transmitted infection screening detected Chlamydia trachomatis infection, which was treated with doxycycline. In the context of MPXV proctitis, it was decided to apply for tecovirimat, the antiviral treatment of choice. The dosage for tecovirimat is weight-based, 600 mg was administered every 12 hours for 14 days (30/08/22–12/09/22). Regarding effectiveness, no new lesions were observed and those already present were regressing, except in the perianal area, where the lesions continued to progress. Therefore, it was decided to administer intravenous cidofovir 5 mg/kg twice weekly (09/09/22, 16/09/22). To avoid toxicity, oral probenecid was administered concomitantly: 2 g 3 hours before and 1 g 2 and 8 hours after completing the perfusion, in addition to 0.9% saline solution 1000 ml 1 h before. After the treatment, there was a progression of lesions in the right inguinal region, palpating left inguinal adenopathy and intense involvement of the testicle, groin and perineal area.

Conclusion and Relevance In contrast to previous cases of patients whose CD4+ lymphocyte levels were above 500 cells/ml, the treatment with tecovirimat and cidofovir in this patient did not achieve a satisfactory response due to the continuous appearance of new lesions. The severe immunosuppression could probably explain the aggressive development of the disease.

Conflict of Interest No conflict of interest