Tecovirimat for Monkeypox Infection Shows Clinical Benefit in Patients With, Without HIV

There were no observable differences in treatment outcomes between patients who are HIV-negative and patients with HIV (PWH) who were treated with tecovirimat (Tpoxx; SIGA Technologies) for monkeypox virus (MPXV) infection, according to the results of a study published in the Annals of Internal Medicine.

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MPXV originates from the same genus as smallpox and the first recognized human case occurred in the 1970s in the Democratic Republic of Congo. Most outbreaks have occurred in sub-Saharan Africa, with international outbreaks being caused by travel or imported infected animals.

The current epidemiology suggests that infection is almost exclusively in men who have sex with men (MSM). A disproportionate number of MSM also had HIV and have an elevated risk for MPXV, with 35% to 47% of cases occurring in this population.

“The epidemiology of the current outbreak differs significantly from prior instances in that MPXV infection is occurring almost exclusively among (MSM) and has been associated with significant rates of coincident sexually transmitted infections,” the authors wrote. “In addition to known skin-to-skin and respiratory transmission, MPXV has been identified in semen as well as fecal and rectal specimens, suggesting the potential for infection via exposure to bodily fluids.”

Tecovirimat is currently being studied as a treatment for MPX. Some literature suggests that it is safe and effective, but there are no clinical data related to treatment outcomes between PWH and patients who are HIV-negative.

The current retrospective cohort study attempts to compare the clinical outcomes, demographic, clinical presentation, concurrent infections, and treatment safety of patients with and without HIV who received tecovirimat for MPXV infection. The study was conducted during the 2022 MPXV outbreak and included 196 patients (mostly men) who were treated with tecovirimat, of whom 154 were MPXV-positive and 72 were PWH.

Following treatment, investigators observed no major clinical differences (treatment outcome and clinical presentation) between people who are HIV-positive versus HIV-negative who took tecovirimat for MPXV. Both arms experienced clinical improvement in a short timeframe, and most patients were pain-free by the end of treatment. Further, hospitalization rates were similar between both cohorts.

PWH also started tecovirimat therapy before patients who were HIV-negative and took pre-exposure prophylaxis (PrEP), suggesting that access to tecovirimat was not influenced by unequal access to care. However, most PWH identified as Black or Hispanic and highlights that patient demographics could be a contributing factor of HIV-burden.

“Although it remains unclear how the incidence and demographic features of the current mpox outbreak will develop going forward, the current scenario requires better understanding of both disease and treatment in those persons who bear the greatest burden of disease to date—primarily MSM and PWH,” the study authors wrote. “Tecovirimat is a promising treatment whose efficacy will hopefully be borne out in future rigorous studies.”

The main symptoms of MPXV among PWH include skin lesions, fever, and diarrhea beginning day 1. Patients who were HIV-negative were more likely to experience a prodrome (fever, fatigue, malaise) and possible lymphadenopathy. The drug was generally well-tolerated by most patients, with 22% experiencing nonsevere adverse events (AEs).

Study limitations included that it did not involve a control group of patients with MPXV who did not receive tecovirimat. There were also missing data at follow-up, possible selection bias, and most PWH had a well-controlled disease.

“Additional studies to show the effect of tecovirimat on disease progression and to more closely track the timeline of symptom resolution are needed,” the study authors wrote.

Reference

McLean J, Stoeckle K, Huang S, et al. Tecovirimat Treatment of People With HIV During the 2022 Mpox Outbreak. Ann Intern Med. 2023. https://doi.org/10.7326/M22-3132