One of the first studies evaluating the use of tecovirimat to treat monkeypox symptoms and skin lesions has been published. In 25 patients with monkeypox, the antiviral drug approved for smallpox treatment appeared to be safe and effective (MPX).
According to a UC Davis Health study, the antiviral tecovirimat appears to be safe and effective for treating monkeypox symptoms and skin lesions. The study is one of the first to assess and report on the outcomes of using this antiviral to treat patients with monkeypox.
Tecovirimat (TPOXX) is an antiviral drug approved by the FDA for the treatment of smallpox. It inhibits the work of the protein involved in the release of the enveloped virus, limiting viral spread in the body. The Centers for Disease Control and Prevention (CDC) recently approved the compassionate use of tecovirimat to treat adults and children with orthopoxvirus infections, including monkeypox.
UC Davis infectious disease experts presented findings from 25 patients with monkeypox who received tecovirimat therapy in a research letter published in JAMA.
“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. She is an adult infectious disease specialist at UC Davis Health.
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.
Angel Desai
Treating monkeypox with tecovirimat
As of August 22, 2022, there had been over 45,500 cases of monkeypox worldwide. While most symptoms go away on their own in 2-4 weeks, a recent study found that 13% of patients required hospitalization. The new study included patients referred to UC Davis Medical Center between June 3 and August 13, 2022, primarily through the Sacramento County Department of Public Health.
Oral tecovirimat treatment was offered to patients who had skin lesions in multiple body parts or in sensitive areas such as the face or genital region. The treatment was weight-based, administered every 8 or 12 hours, and was administered within 30 minutes of a high-fat meal.
The researchers collected clinical data at the first in-person evaluation for treatment and by in-person or telephone interview on day 7 and day 21 following the beginning of therapy. In total, 25 patients with confirmed monkeypox infection completed a course of tecovirimat therapy. All were male. Their age ranged between 27 and 76 years (the median age was 40). 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.
Symptoms in patients with monkeypox, MPX
The study discovered that 92% of patients had genital or anal lesions. While all patients had painful lesions, approximately half of them had fewer than ten lesions on their entire body. Patients had symptoms or lesions for an average of 12 days before beginning antiviral treatment. The most common symptom was fever (76% of patients), followed by fatigue (32%), sore throat (20%), and chills (20%). Backache (12%), muscle pain (8%), nausea (4%) and diarrhea (4%) were among the other symptoms.
All patients finished their tecovirimat therapy and tolerated it well. With the exception of one patient, they were all treated for two weeks. 40% of patients had healed from their lesions by the seventh day of therapy. 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 diarrhea (8%).
“We must be extremely cautious in how we interpret the data. It is difficult to distinguish between side effects caused by therapy and those caused by infection” co-author and infectious diseases expert George Thompson Thompson is a professor in the Departments of Internal Medicine, Infectious Diseases, and Medical Microbiology and Immunology at the University of California, Davis School of Medicine.
The study was small, and there was no control group. As a result, evaluating antiviral efficacy in terms of symptom duration and severity was restricted. In addition, the time between the onset of symptoms and the start of antiviral therapy varied between patients.
