{Reference Type}: Case Reports {Title}: Treatment Failure in Patient with Severe Mpox and Untreated HIV, Maryland, USA. {Author}: Filippov E;Duhan S;Lehman L;Keisham B;Sethi V; {Journal}: Emerg Infect Dis {Volume}: 29 {Issue}: 6 {Year}: 2023 06 12 {Factor}: 16.126 {DOI}: 10.3201/eid2906.230059 {Abstract}: A 33-year-old man in Baltimore, Maryland, USA, with untreated HIV infection had a 74-day course of mpox with multiorgan system involvement and unique clinical findings. In this clinical experience combining 3 novel therapeutic regimens, this patient died from severe mpox in the context of untreated HIV and advanced immunodeficiency.