A new analysis supports using the smallpox antiviral tecovirimat (TPOXX/ST-246) in patients with HIV showing the first symptoms of the human smallpox disease mpox (monkeypox), caused by the variola virus.
In a small prospective matched cohort analysis, people with HIV (PWH) and mpox disease who received tecovirimat within 7 days of symptom onset were 13 times less likely to experience progression, compared with PWH not prescribed tecovirimat within that window. In a matched cohort of 112 PWH, mpox disease progression occurred in 5.4% in an early tecovirimat group and in 26.8% in a late- or no-tecovirimat group, for a paired odds ratio of 13.00 (95% CI, 1.71-99.40; P = .002).
"Results of the present study suggest that tecovirimat treatment should be started early at the time of suspected mpox diagnosis in all PWH, especially in those with nonsuppressed HIV viremia or mucosal site involvement," wrote a team led by Bruce Aldred, MD, of the Division of Infectious Diseases in the Department of Medicine at Emory University School of Medicine in Atlanta, Georgia, in JAMA Internal Medicine. Early symptoms of mpox include skin rash and mucosal lesions, along with viral symptoms such as fever, headache, muscle aches, back pain, low energy, and swollen lymph nodes.
As of March 1 of last year, the United States reported more than 30,000 cases, while cases numbered more than 86,000 worldwide.
Despite a lack of effectiveness data in humans, tecovirimat was widely prescribed to PWH with mpox during the 2022 epidemic, which disproportionately affected PWH, particularly those with low CD4+ T-cell counts or severe mpox clinical manifestations who needed urgent therapy. Developed to treat smallpox, tecovirimat has antiviral activity against other orthopoxviruses and has reduced mpox-related morbidity and mortality in animals.
Based on the animal data, approval was granted by the US Food and Drug Administration for human mpox treatment. Dr Aldred and colleagues undertook this cohort analysis in the absence of human data and with the postoutbreak decline in cases impeding recruitment to a full-scale clinical trial.
Study Design
The preponderantly Black cohort included 112 PWH diagnosed with mpox at four Atlanta hospitals from June 1 to October 7, 2022. Patients were grouped in an early cohort receiving tecovirimat within 7 days of symptom onset or a no or late cohort (no tecovirimat or treatment more than 7 days after symptom onset. Multivariate logistic regression models identified factors associated with progression, defined as development of at least one severe CDC mpox criterion after symptom day 7.
The cohorts were then matched 1:1 using propensity scores based on the identified factors, and mpox disease progression was compared.
Of 112 PWH, 56 receive early tecovirimat and 56 received no or late treatment. In the early group, the median (interquartile range [IQR]) age was 35 (30-42) years; 54 individuals (96.4%) were cisgender men, 46 (82.1%) were Black, and 10 (17.9%) were, variously, White, American Indian, Alaska Native, Asian, Native Hawaiian or Other Pacific Islander, or of unknown race.
In the late- or no-tecovirimat group, the median (IQR) age was 36 (32-43) years; 54 (96.4%) were cisgender men, 49 (87.5%) were Black, and seven (12.5%) were individuals of other or unknown race. Mpox disease progression occurred in three PWH in the early-tecovirimat group and 15 PWH (26.8%) in the late- or no-tecovirimat group.
Dr Aldred and colleagues acknowledged that more research is needed to confirm the findings and cited several study limitations. These included the small sample size, the preponderance of Black participants, and the possibility that unmatched confounding variables could have led to the observation of fewer cases of severe disease in the early-tecovirimat cohort.
This study was supported by a grant from the Emory Center for AIDS Research. Coauthors reported grants from various institutes at the National Institutes of Health as well as from multiple pharmaceutical companies.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.