Pharmaceutical Technology

SIGA scores HHS contract for smallpox vaccine Tpoxx worth $113m

The company’s Tpoxx vaccine is used to treat orthopoxvirus but is only approved for treating smallpox by the FDA.

The US Department of Health and Human Services (HHS) has exercised a procurement option for SIGA Technologies’ oral Tpoxx (tecovirimat).

The contract is worth approximately $113m and builds on the previous procurement agreement with the US HHS for Tpoxx. In July 2023, the US HHS ordered approximately $138m worth of Tpoxx vaccine, of which $113m worth of oral Tpoxx was set to be delivered last year and the delivery of an intravenous formulation was planned for this year.

Tpoxx is designed to treat the orthopoxvirus, which can cause smallpox, mpox (monkeypox), cowpox, and vaccinia virus. It is approved by the US Food and Drug Administration (FDA) to only treat smallpox. However, the vaccine has been approved to treat mpox, cowpox, and vaccinia complications in addition to smallpox by the European Medicines Agency (EMA) and the UK’s Medicines and Healthcare Products Regulatory Agency (MHRA).

SIGA is also conducting a confirmatory Phase III trial (NCT05534984) to establish Tpoxx’s efficacy in treating mpox. The trial is sponsored by the National Institute of Allergy and Infectious Diseases (NIAID) and is expected to conclude in mid-2025.

Tpoxx’s main competitor is Bavarian Nordic’s Jynneos, which is also the only US FDA-approved vaccine for mpox. Bavarian Nordic reported DKr5bn ($725m) in sales for Jynneos in 2023.

Following the mpox outbreak in 2022, there was an increased demand for mpox vaccines. Despite a decrease in mpox cases over the last year, demand persists for the Tpoxx and Jynneos as multiple countries continue to buy vaccines to mitigate the risks of potential mpox outbreaks.

Last month, SIGA signed an agreement with member states of the Association of Southeast Asian Nations (ASEAN) group to supply Tpoxx. ASEAN consists of ten South Asian member states, including Singapore, Thailand, Malaysia, and Cambodia.

In October 2023, the US-based company reported the creation of a joint procurement framework contract by the European Commission’s DG Health Emergency Preparedness and Response Authority (HERA) under which participating countries from the European Union (EU) and the European Free Trade Association (EFTA) can order oral Tpoxx. Under this mechanism, SIGA reported Tpoxx orders worth approximately $18m from 13 countries in Q4 2023.