Key Points
Question Is use of tecovirimat within 7 days of mpox symptom onset associated with lower rates of mpox disease progression among people with HIV (PWH)?
Findings In this cohort study including 112 PWH after propensity matching, those treated with tecovirimat within 7 days of mpox symptom onset compared with those who were treated after 7 days or who did not receive tecovirimat were 13 times less likely to progress to severe mpox disease.
Meaning The findings of this study support the use of tecovirimat in all PWH as soon as mpox is suspected.
Abstract
Importance Despite a lack of effectiveness data in humans, tecovirimat was widely prescribed to people with HIV (PWH) with mpox during the 2022 mpox epidemic, particularly PWH with low CD4+ T-cell counts or severe mpox clinical manifestations.
Objective To evaluate if PWH with mpox who were treated with tecovirimat within 7 days of symptom onset were less likely to have mpox disease progression.
Design, Setting, and Participants This cohort study included PWH diagnosed with mpox at 4 hospitals in Atlanta, Georgia, between June 1 and October 7, 2022. Patients were grouped according to whether they were treated with tecovirimat within 7 days of mpox symptom onset (early tecovirimat cohort) or they did not receive tecovirimat or received the drug 7 or more days after symptom onset (late or no tecovirimat cohort). Multivariable logistic regression models were used to identify factors associated with progression of mpox disease. The 2 cohorts were then matched 1:1 using propensity scores based on the identified factors, and mpox disease progression was compared.
Exposures Treatment with tecovirimat within 7 days of mpox symptom onset.
Main Outcome and Measures Progression of mpox disease, defined as the development of at least 1 severe mpox criterion established by the US Centers for Disease Control and Prevention, after symptom day 7.
Results After propensity score matching, a total of 112 PWH were included in the analysis; 56 received tecovirimat within 7 days of mpox symptom onset (early tecovirimat group) and 56 were either treated later or did not receive tecovirimat (late or no tecovirimat group). In the early tecovirimat group, the median (IQR) age was 35 (30-42) years; 54 individuals (96.4%) were cisgender men, 46 (82.1%) were Black individuals, and 10 (17.9%) were individuals of other races (American Indian or Alaska Native, Asian, Native Hawaiian or Other Pacific Islander, or White) or 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 individuals, and 7 (12.5%) were individuals of other races or unknown race. Mpox disease progression occurred in 3 PWH (5.4%) in the early tecovirimat group and in 15 PWH (26.8%) in the late or no tecovirimat group (paired odds ratio, 13.00 [95% CI, 1.71-99.40]; P = .002).
Conclusion and Relevance Results of this cohort study support starting tecovirimat in all PWH as soon as an mpox diagnosis is suspected. Additional research is warranted to confirm these findings.
The 2022 global mpox outbreak disproportionately affected people with HIV (PWH).1,2 This population may develop more severe mpox disease manifestations and worse clinical outcomes,3,4 especially individuals with lower CD4+ T-cell counts5 and nonsuppressed HIV viremia,6 highlighting the urgent need for effective therapeutic agents for this population.
Tecovirimat (ST-246), an antiviral agent developed to treat smallpox, has antiviral activity against other orthopoxviruses, including mpox virus. In animal models, tecovirimat was shown to prevent morbidity and mortality associated with mpox, especially when started within 5 days of mpox inoculation.7–9
Based on these data, the US Food and Drug Administration approved tecovirimat for mpox treatment using expanded access for an investigational new drug. Data showing the effectiveness of tecovirimat for treating mpox disease in humans are lacking.10,11 Meeting enrollment goals for a randomized controlled trial assessing the efficacy of tecovirimat for mpox infection (the STOMP [Study of Tecovirimat for Human Monkeypox Virus] trial12) has been challenging due to declining number of mpox cases. We aimed to perform a matched cohort analysis to examine the association between early tecovirimat treatment (started within 7 days of mpox symptom onset) and progression of mpox disease among PWH.
In this prospective matched cohort analysis, PWH with mpox disease who were prescribed tecovirimat within 7 days of symptom onset were significantly less likely to have progression of mpox disease compared with PWH who were not prescribed tecovirimat within 7 days of symptom onset. 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.
This study has limitations. First, it is possible that unmatched confounding variables could have contributed to fewer cases of severe mpox disease being observed in the early tecovirimat cohort. Second, this study has a small sample size and is inadequately powered to examine specific mpox complications or mortality. Third, most of our population (84.8%) were Black individuals, which reflected the population affected by the 2022 mpox outbreak in Atlanta but may limit generalizability to populations with different races and ethnicities. Fourth, the timing of tecovirimat initiation was determined based only on the time that the tecovirimat prescription was written, and we could not confirm if individuals took the medication or for how long. Fifth, we did not evaluate adverse events associated with tecovirimat. A large cohort study previously reported that tecovirimat is well tolerated.11
To our knowledge, this cohort study represents the first controlled analysis of tecovirimat for the treatment of mpox disease in PWH. The findings support starting tecovirimat in all PWH as soon as an mpox diagnosis is suspected. Additional research is needed to confirm these findings.
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