Tpoxx found to be well-tolerated, safe in US monkeypox patients

Orange and black capsules on production line
Orange and black capsules on production line

Fahroni / iStock

Today in Morbidity and Mortality Weekly Report, researchers from the Centers for Disease Control and Prevention (CDC) provided data on safety outcomes on 369 patients who receiving the monkeypox antiviral drug tecovirimat (Tpoxx), noting that few adverse events were reported.

In related news, a study spotlighted neurologic complications such as encephalitis and seizures in monkeypox patients, Los Angeles County is investigating the death of an infected person, and federal officials are considering widening the vaccine pool to include people with HIV.

Side effects in 3.5% of Tpoxx users

Tpoxx was developed and tested for treating smallpox, but it is currently widely used in the United States to treat monkeypox patients under a Food and Drug Administration Expanded Access Investigational New Drug (EA-IND) ruling.

Of the 369 patients in today's study who were administered Tpoxx orally, adverse events were reported in 3.5% of patient, with only one adverse event classified as serious.

Roughly half of those administered the drug had HIV, and the median interval from initiation of tecovirimat to subjective improvement was 3 days and did not differ by HIV infection status, the authors said. Tecovirimat was taken for a prescribed 14-day regimen.

"Although this report could not evaluate efficacy, clinicians are encouraged to continue following CDC guidelines for tecovirimat use in patients with severe disease or at risk for severe disease," the authors said.

Tpoxx recipients were 97.7% male, with a median age of 36.5 years. Among patients with available data, 38.8% were reported to be non-Hispanic White, 34.7% were Hispanic or Latino, and 17.9% were non-Hispanic Black or African American.

The CDC reported 230 more monkeypox cases yesterday, raising the total to 21,504.

Monkeypox tied to neurologic complications

New research from the University College London (UCL) shows some monkeypox patients develop significant neurological complications, including encephalitis (brain inflammation), seizures, and confusion. The study was published in eClinicalMedicine yesterday.

The meta-analysis combed 19 cohort studies that included a total of 1,512 monkeypox patients. The investigators found that 2.7% patients experienced seizures (95% confidence interval [CI], 0.7% to 10.2%), confusion 2.4% (95% CI, 1.1% to 5.2%), and encephalitis 2.0% (95% CI, 0.5% to 8.2%). The patients were seen in outbreaks in the United States, Nigeria, Democratic Republic of the Congo, Republic of Congo, and the United Kingdom.

The study findings include patient data from previous outbreaks and a mix of virus clades, the authors warned.

In a press release, senior author Jonathan Rogers, MB BChir, of UCL, said, "We found that severe neurological complications such as encephalitis and seizures, while rare, have been seen in enough monkeypox cases to warrant concern, so our study highlights a need for further investigation."

Los Angeles investigating monkeypox death

Los Angeles County is investigating a death in a monkeypox patient, which would be the second such US case. Texas reported the death of a monkeypox patient in Harris County earlier this month, and officials in both cases are investigating what role monkeypox played in the fatalities.

In other US news, the Associated Press is reporting the White House is considering recommending monkeypox vaccination to all men with HIV and those recently diagnosed as having other sexually transmitted infections (STIs).

The recommendation may change, as a recent CDC study found 38% of those with monkeypox infections had been diagnosed with HIV, and 41% of monkeypox patients had been diagnosed with an STI. Worldwide, 44.9% of monkeypox patients with known HIV status are positive.

The CDC now recommends vaccination for close contacts and men who have sex with men (multiple partners) in an area with high visual spread.

Globally, the World Health Organization said in a new epidemiologic report that there have been 18 deaths globally in the current outbreak.

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