Therapeutics for treating mpox in humans
What is the aim of this review?
There are no drugs licenced specifically for treating mpox, but some drugs that are licenced for treating similar viral infections, such as smallpox, are authorized for treating mpox during an outbreak. The effects of these drugs have not yet been studied in randomized trials in people with mpox. Randomized trials include at least two treatment groups, such as one receiving the drug and one receiving a placebo, where the people recruited for the trial are randomly allocated to either group. This review summarizes evidence on the safety and effectiveness of treatments for mpox in humans, which was completed in two parts: a review of evidence from randomized controlled trials (RCTs) and a review of safety data from non‐randomized studies.
Randomized controlled trials review
We searched for RCTs on both the safety and effectiveness of treatments for mpox.
Non‐randomized studies review
We searched for non‐randomized studies on the safety of treatments for mpox only.
Key messages
Randomized controlled trials review
When their results become available, data from five ongoing RCTs will allow us to compare safety and effectiveness outcomes between people who receive treatment for mpox and those who do not. We will be able to compare patient‐important outcomes for different treatment options.
Non‐randomized studies review
Tecovirimat, an oral anti‐viral drug, is safe and well tolerated in individuals with mpox, based on evidence from non‐randomized studies. Three people treated with brincidofovir, another oral anti‐viral drug, experienced a sudden increase in one liver enzyme called alanine transaminase (ALT), and their treatment was discontinued as a result. This result may indicate mild liver injury caused by the drug. More severe forms of drug‐induced liver injury can cause serious liver damage and even liver failure, so this should be closely monitored in people with mpox who are treated with brincidofovir.
What was studied in the review?
Randomized controlled trials review
This review identified five ongoing clinical trials assessing tecovirimat for treating people with mpox. They aim to recruit a total of 1750 people in the USA, Canada, Brazil, Switzerland, UK, and Democratic Republic of Congo.
Non‐randomized studies review
This review identified three non‐randomized studies conducted in the Central African Republic, UK and USA. A total of 355 people received tecovirimat, and three received brincidofovir as their treatment drug.
What are the main results of the review?
Randomized controlled trials review
There is currently no evidence from RCTs available, but the five ongoing trials identified will be assessed in future updates of this review.
Non‐randomized studies review
Three non‐randomized studies assessed safety in 358 people treated for mpox (355 received tecovirimat, 3 received brincidofovir). Very few of the people who received tecovirimat reported unwanted or harmful effects (16 out of 355 people). These included 11 mild unwanted or harmful effects, two mental health outcomes, and one case of increased liver enzymes. There was also one death and one case of anaemia, but neither of these was thought to be related to the study drug.
All three people who received brincidofovir reported an increase in alanine transaminase (ALT; a liver enzyme released by liver cells when they are damaged) which led to discontinuation of their treatment. In at least two of the cases treated with brincidofovir, their increased alanine transaminase level may indicate mild drug‐induced liver injury. We do not know whether this would have progressed to become more serious if treatment had not been discontinued. Liver enzymes should be carefully monitored in individuals receiving this drug.
What are the limitations of the evidence?
Randomized controlled trials review
There is currently no evidence from RCTs available.
Non‐randomized studies review
People included in the studies all received the treatment, so we are unable to compare these results against people with a placebo or no treatment. The study investigating brincidofovir was also very small.
How up to date is this review?
Randomized controlled trials review
The review authors searched for studies available up to 25 January 2023.
Non‐randomized studies review
The review authors searched for studies available up to 22 September 2022.