In a research letter published in JAMA, infectious disease experts reported on 25 monkeypox patients given tecovirimat therapy, with data showing that it is safe and effective for the treatment of monkeypox symptoms and skin lesions.
The recent global outbreak of monkeypox has led to more than 45 500 cases as of August 22, 2022. While symptoms usually resolve on their own in 2–4 weeks, a recent study showed that 13% of patients needed hospitalisation.
Tecovirimat (TPOXX) is an FDA-approved antiviral drug for the treatment of smallpox which limits viral spread in the body by inhibiting the release of the enveloped virus. Recently, the Centers for Disease Control and Prevention (CDC) allowed physicians to prescribe tecovirimat on a compassionate use basis to treat adults and children with orthopoxvirus infections, including monkeypox.
“We have very limited clinical data on the use of tecovirimat for monkeypox infection. There is much to learn about the natural progression of the disease and how tecovirimat and other antivirals may affect it,” said lead author Angel Desai, an adult infectious disease specialist.
The new study included patients referred to UC Davis Medical Center, between June 3 and August 13, 2022.
Patients with skin lesions in multiple body parts or in sensitive areas such as the face or genital region were offered oral tecovirimat treatment. The treatment was weight-based, given every 8 or 12 hours, and was taken within 30 minutes of a high-fat meal.
The researchers collected clinical data on evaluation for treatment and on day 7 and day 21 following the beginning of therapy.
In total, 25 male patients (ages 27–76 years) with confirmed monkeypox infection completed a course of tecovirimat therapy. Nine patients had HIV.
Only one patient had the smallpox vaccine (taken more than 25 years ago) and four others received a dose of JYNNEOS vaccination after symptoms started.
The study found that 92% of patients had lesions in their genital or anal area. While all patients had painful lesions, around half had fewer than 10 lesions over their entire body.
On average, the patients had symptoms or lesions for 12 days before they started their antiviral treatment. Fever was the most common symptom (76% of the patients), followed by fatigue (32%), sore throat (20%) and chills (20%). Other symptoms included backache (12%), muscle pain (8%), nausea (4%) and diarrhoea (4%).
All patients completed the tecovirimat therapy and tolerated their treatment well. They were treated for two weeks, except for one patient who was treated for 21 days.
On day 7 of therapy, 40% of patients had healed from their lesions. By day 21, 92% had healed and were pain-free.
The most reported adverse events on day 7 of therapy included: fatigue (28%), headache (20%), nausea (16%), itching (8%) and diarrhoea (8%).
“We have to be very careful in how we interpret the data. It is hard to differentiate the side effects due to therapy from those caused by the infection,” cautioned infectious diseases expert and co-author George Thompson.
This small study lacked a control group, limiting assessment of antiviral efficacy in terms of symptom duration and severity. Also, the time from symptom onset to starting the antiviral therapy varied among the patients.
The researchers called for large-scale studies to explore antiviral efficacy dosing and adverse events.
Source: UC Davis Health
