HIV status does not affect Tecovirimat treatment outcomes for Mpox virus infection

In a recent commentary published in the Annals of Internal Medicine, researchers performed a retrospective cohort study among patients treated with tecovirimat for human immunodeficiency virus (HIV)-infected mpox virus (MPXV) patients between June and August 2022 in New York City, United States of America (USA).

Study: Tecovirimat Treatment of People With HIV During the 2022 Mpox Outbreak. Image Credit: Dotted Yeti / Shutterstock

Background

Tecovirimat, originally developed and approved for smallpox treatment, has been widely used in the current MPXV outbreak. Reports have confirmed that tecovirimat use resolves >90% of MPXV disease symptoms and is well-tolerated, resulting in only mild adverse effects.

The scientific literature on safety and clinical outcomes of tecovirimat treatment among MPXV cases is increasing. However, there is a shortage of studies comparing the tecovirimat treatment outcomes for people having MPXV infection while living with HIV [PWH] and without HIV.

About the study

In the present study, researchers recruited all patients who initiated treatment with tecovirimat based on the Centers for Disease Control and Prevention (CDC) eligibility guidelines under the EA-IND protocol at NewYork-Presbyterian’s Weill Cornell or Columbia University Medical Centers between 20 June and 29 August 2022.

The study participants had confirmed MPXV infection and completed at least two follow-up visits in the inpatient, outpatient, and telehealth settings.

The team examined safety outcomes and the appearance of new lesions at 48 hours among participants who completed at least one follow-up visit. In addition, they monitored clinical outcomes, including resolution of pain and persistent disease symptoms by the end of the treatment among those completing at least one follow-up visit after treatment completion.

In total, 196 patients initiated treatment with tecovirimat, of which 154 had confirmed MPXV infection, and 72 and 82 were PWH and HIV-negative, respectively. The remaining 134 individuals completed at least one follow-up visit, and 88 completed a follow-up visit after the completion of treatment. Strikingly, all patients in this cohort study were men.

Results

The study authors observed no substantial variations in clinical presentation or treatment outcomes between the two groups comprising PWH and HIV-negative patients infected with MPXV and receiving tecovirimat treatment. In this study, most PWH were older (mean age, 39 vs. 32 years) and self-identified as Black or Hispanic. Of all, 14 HIV-positive individuals had a viral load >1000 copies/mL, while 70% of HIV-negative individuals took HIV PrEP at the first study visit.

PWH more likely reported skin lesions, fever, and diarrhea upon illness onset. Conversely, HIV-negative patients experienced a prodrome and developed additional symptoms, including lymphadenopathy, much later. Though the significance of this discrepancy is unclear, it might be leading to diagnostic ambiguity in PWH having MPXV or herpes simplex virus (HSV), which do not manifest as enlarged lymph nodes. Strikingly, both group patients similarly contracted severe mpox disease, and there were no marked inter-group differences apart from treatment eligibility criteria for HIV infection.

While previous reports have suggested that more PWH than HIV-negative patients sought hospitalization for mpox, in this study, the authors observed no apparent differences in their hospitalization rates, likely due to a low proportion of patients in this cohort with a CD4 count of <0.20 × 10⁹ cells/L. More work could confirm the need for therapeutic decision-making when comparing mpox infection severity between PWH with low CD4 counts and other cases.

Importantly, consistent with prior reports, tecovirimat treatment was well tolerated and fetched no serious adverse events in this case series. The authors noted fatigue or malaise in some cases, which are also mpox infection symptoms; and, therefore, cannot be attributed entirely to tecovirimat medication.

Finally, treatment outcomes after tecovirimat therapy were encouraging regardless of the HIV status of patients. The pain was resolved for nearly all patients by the time treatment ended. Similarly, skin lesions that developed >48 hours after treatment initiation or persisted after treatment completion resolved among PWH and HIV-negative patients. In fact, all persistent symptoms healed by the time of treatment completion.

Future studies could confirm whether shorter times to treatment initiation would have altered treatment outcomes for tecovirimat. Additionally, studies should demonstrate the effect of tecovirimat on the progression to severe disease and symptom resolution timelines for PWH and HIV-negative patients. Notably, PWH began tecovirimat therapy sooner, and HIV-negative patients were taking PrEP.

Conclusions

The findings of the Study of Tecovirimat for Human Mpox Virus (STOMP) trial evaluating the efficacy of tecovirimat against MPXV are not yet available. So far, only case series have demonstrated the efficacy and safety of tecovirimat, the antiviral agent most used for MPXV treatment.

The current preliminary study is the first of its kind to compare tecovirimat treatment outcomes between HIV patients and those without HIV infection. It fills the knowledge gap about patient experience with tecovirimat treatment and could help counsel patients seeking mpox treatment.

Since MSM and PWH currently share a disproportionate and the highest burden of MPXV disease, a better understanding of both disease symptoms and treatment outcomes in these people is crucial. Despite the lack of clarity on how the current mpox outbreak will develop, future studies will fetch evidence favoring tecovirimat use as a promising therapy for MPXV infections.

Written by

Neha Mathur

Neha is a digital marketing professional based in Gurugram, India. She has a Master’s degree from the University of Rajasthan with a specialization in Biotechnology in 2008. She has experience in pre-clinical research as part of her research project in The Department of Toxicology at the prestigious Central Drug Research Institute (CDRI), Lucknow, India. She also holds a certification in C++ programming.