The U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) are reviewing various treatments for people infected with the monkeypox virus (MPXV). 'Currently, there is no treatment approved specifically for monkeypox virus infections,' states the U.S. NIH. However, the U.S. NIH says 'several antiviral medications used to treat smallpox and other conditions may help patients infected with monkeypox.'
On August 4, 2022, the U.S. CDC confirmed Tecovirimat (also known as TPOXX® or ST-246®) is FDA-approved for treating human smallpox disease caused by Variola virus in adults and children under an FDA authority called Expanded Access. However, its use for other orthopoxvirus infections, including monkeypox, is not approved by the FDA.
Monkeypox Treatment Options
The U.S. CDC's Interim Clinical Guidance for the Treatment of Monkeypox was published on June 22, 2022, and updated on July 28, 2022. In addition, the following medical countermeasures may be available from the U.S. Strategic National Stockpile (SNS) as options for treating monkeypox.
TPOXX® (tecovirimat) is an antiviral medication that the U.S. FDA approved in 2018 to treat smallpox in adults and children. Unfortunately, data are unavailable on the effectiveness of TPOXX in treating monkeypox infections in people. Still, studies using a variety of animal species have shown that TPOXX is effective in treating diseases caused by orthopoxviruses. The EMA issued its authorization EMEA/H/C/005248 in January 2022.
Tembexa (Brincidofovir) is an antiviral medication approved by the FDA on June 4, 2021, for treating human smallpox disease. Tembexa has shown to be effective against orthopoxviruses in vitro and in animal studies.
Vistide (Cidofovir) is an antiviral medication approved by the FDA for treating cytomegalovirus retinitis in patients with AIDS. However, data on Cidofovir's effectiveness in treating human monkeypox cases is unavailable.
Vaccinia Immune Globulin Intravenous (VIGIV) is licensed by FDA (2005) for the treatment of complications due to vaccinia vaccination, including eczema vaccinatum, progressive vaccinia, severe generalized vaccinia, and vaccinia infections in individuals who have skin conditions, and aberrant infections induced by vaccinia virus (except in cases of isolated keratitis). The U.S. CDC holds an expanded access protocol that allows VIGIV to treat orthopoxviruses (including monkeypox) in an outbreak. Data are not available on VIG's effectiveness in treating monkeypox virus infection. VIG can be considered for prophylactic use in an exposed person with severe immunodeficiency in T-cell function for which smallpox vaccination following exposure to monkeypox virus is contraindicated. VIGIV is not commercially available but can be made available through the SNS to treat smallpox vaccine complications in patients with serious clinical manifestations.
Monkeypox Treatment Clinical Considerations for Children
The U.S. CDC published clinical management considerations of monkeypox for people younger than 18 years old on July 26, 2022. Tecovirimat is the first-line medication to treat monkeypox in children and adolescents. However, cases should be considered independently. Information for Healthcare Professionals was published in June 2022. And children and adolescents with exposure to people with suspected or confirmed monkeypox may be eligible for post-exposure prophylaxis with vaccination, immune globulin, or antiviral medication.
Monkeypox Treatment News
August 9, 2022 - SIGA Technologies, Inc. announced the exercise of procurement options for the delivery to the U.S. government of intravenous formulation of TPOXX treatment courses valued at approximately $26 million.
August 4, 2022 - NanoViricides, Inc. announced it had begun drug development to combat the monkeypox virus. Specifically, the Company has initiated a program to screen its library of broad-spectrum antiviral nanoviricides against certain poxviruses to develop broad-spectrum poxvirus therapeutics that act by mechanisms other than TPOXX®.
August 3, 2022 - The NEJM published a Perspective: Tecovirimat and the Treatment of Monkeypox — Past, Present, and Future Considerations.
August 2, 2022 - The Lancet published: Monkeypox: how will we know if the treatments work?
July 24, 2022 - The WHO published: Responding to the monkeypox outbreak: perspectives of clinicians treating patients with the disease.
July 22, 2022 - The U.S. CDC confirmed that the administrative process has become easier for healthcare providers to provide tecovirimat (TPOXX) to patients with monkeypox under the expanded access investigational drug (EA-IND).
July 13, 2022 - The U.K. Guidelines summary provides information and advice for healthcare professionals on monkeypox. It includes updated vaccination recommendations and a useful contact tracing table. For a complete set of recommendations, refer to the original guidance.
July 12, 2022 - SIGA Technologies, Inc. announced approximately $28 million of procurement orders for oral TPOXX® (tecovirimat), including roughly $2 million for initial procurement by two new international jurisdictions and about $26 million for procurement by Canada. One of the new jurisdictions is in Europe, and the other new jurisdiction is in the Asia Pacific region.
June 28, 2022 - The journal Springer published an Opinion article: Prevention and Treatment of Monkeypox.
June 27, 2022 - The WHO's latest situation update stated: That tecorivimat (TPOXX) is an antiviral drug with recent regulatory approval from the European Medicines Agency for orthopovirus-associated infections, including monkeypox, based on animal models and data for safety, pharmacokinetics, and pharmacodynamics in humans. Therefore, it is expected that reliable and interpretable results on its safety and efficacy will soon become available.
June 23, 2022 - SIGA Technologies, Inc. announced approximately $13 million of procurement orders for oral TPOXX, including $11 million for initial procurement from two new international jurisdictions and an approximate $2 million order from a country in the Asia Pacific region that has an established contract for oral TPOXX.
June 22, 2022 - The U.S. CDC published: Interim Clinical Guidance for the Treatment of Monkeypox.
June 17, 2022 - The UKHSA published: Recommendations for using pre and post-exposure vaccination during a monkeypox incident.