Rapid improvement of severe Mpox lesions with oral tecovirimat

Dear Editor, Recently in this journal Hermanussen et al. provided virologic details of individuals with severe Mpox treated with oral tecovirimat and we provided a description of cases treated with intravenous cidofovir. The aim of this case‐series is to describe a multicenter Italian experience on the use of oral tecovirimat for the treatment of severe Mpox infection and provide a clinical perspective on the management of challenging cases. Overall, 9 individuals with PCR‐confirmed severe Mpox virus infection were included in this case‐series. All were Caucasian men who have sex with men (MSM): 2/9 (22%) were HIV pre‐exposure prophylaxis users, 2/9 (33%) were living with HIV, receiving antiretroviral therapy and in an optimal immune‐virologic status, and 1/9 (11%) were diagnosed with HIV concurrently to Mpox infection, in a state of immunodeficiency: CD4 count 73 cells/ microL, HIV‐RNA 72.445 copies/mL (case 3). No other immunodeficiencies or concomitant immunosuppressive medications were reported; none disclosed receiving previous smallpox or recent monkeypox vaccination. All reported high‐risk sexual behaviors in the 3 months before Mpox diagnosis, 2/9 (22%) were chemsex users and 4/9 (44%) had a previous sexually transmitted infection (STI). The complete characteristics of the included participants are reported in Table 1. Individuals were treated with antiviral therapy with oral tecovirimat at 600mg twice daily dosage for 14 days; indication for tecovirimat treatment was made within the single center according with the severity of the disease. Reasons for oral tecovirimat prescription were: severe cutaneous lesions (cases 1, 3, 6, 7), with superinfection, pharyngitis with dyspnea (case 2), necrotized genital lesions and penile edema (cases 4, 5, 9) and severe proctitis with uncontrolled pain (case 8) (Table 1). Overall, the number of lesions was more frequently between 5 and 10, with a vesicular‐pustular rash and mucosal involvement among 5/9 (55%) individuals. All reported presence of fever, 2/9 (22%) lethargy, 4/9 (44%) pharyngitis, and 8/9 (89%) lymphadenopathy. Tecovirimat was prescribed after a median 8 days (interquartile range [IQR]: 6–14) from symptoms onset and 5 days (IQR: 3–7) from Mpox diagnosis. Overall, 3 individuals required hospitalization (cases 2, 3, 5) and given the presence of necrotizing lesions case 3 required surgical debridement. Lesions and symptoms improvement was observed following a median 3 days (IQR: 1.5–4.5) from tecovirimat prescription, 8 days (IQR: 6–13) from Mpox diagnosis and 12 days (IQR: 8–21) from symptoms onset. The complete resolution of symptoms was observed among all individuals with no sequalae: after a median 12 days (IQR: 5.5–17) from tecovirimat prescription, 19 days (IQR: 11.5–27.5) from Mpox diagnosis and 22 days (IQR: 19–32) from symptoms onset. Moreover, no new onset lesions or symptoms were reported following the beginning of tecovirimat. Clinical pictures of lesions over follow‐up among selected cases are presented in Figure 1. No severe adverse events related to the medication were reported, except grade one diarrhea and anorexia among one individual; no serious laboratories abnormalities were detected, except grade one transaminases toxicity following antiviral therapy. Moreover, 7/9 (78%) required other medicants, including treatment of superinfection and concurrent STIs and pain management. In this case‐series oral tecovirimat confirmed to be well tolerated by all individuals, without severe adverse events or laboratory abnormalities. All MSM diagnosed with Mpox achieved full clinical healing without severe sequelae. We observed a significant and very rapid improvement of lesions and symptoms following oral tecovirimat prescription, often after less than 3 days, similarly to what observed in other cohorts. Notably, among case 3, following more than two months of Mpox symptoms and use of topical cidofovir, clinical improvement was reached within 3 days from tecovirimat prescription and the drug