Emergent wraps up purchase of Chimerix's potential monkeypox treatment Tembexa

With the monkeypox virus evolving—just as the coronavirus before it—adding new products to combat its spread is a key priority for the U.S.

Monday, Emergent BioSolutions took a step toward being able to address the need, completing its acquisition of smallpox oral antiviral Tembexa.

The deal with North Carolina-based Chimerix for worldwide rights to the drug calls for an upfront fee of $238 million plus milestone payments of up to $124 million contingent on the U.S. exercising supply options. 

The companies first announced the deal in May. More recently, the Biomedical Advanced Research and Development Authority helped facilitate the transaction by signing a 10-year contract worth up to $680 million to acquire up to 1.7 million courses of Tembexa.

That agreement cleared the way for Emergent—with its available manufacturing capacity—to gain the rights to Tembexa. 

Tembexa won FDA approval last year to treat smallpox. In that indication, it joins Siga Technologies’ Tpoxx, which was sanctioned in 2018. In May of this year, Tpoxx’s label was expanded with an intravenous formulation for those who have trouble swallowing tablets. The difference between the nods is Tembexa’s covers neonatal children.

Since the emergence of monkeypox in the U.S.—and given its similarities to smallpox—the government has made Tpoxx available under an expanded access program. The Tpoxx situation suggests that Tembexa may also be utilized against monkeypox.

Emergent also produces a smallpox vaccine, ACAM2000, which was approved in 2007 but has yet to be endorsed to prevent monkeypox. The U.S. has relied on Bavarian Nordic's Jynneos vaccine to combat the spread of monkeypox.

Despite the eradication of smallpox in the late 1970s, the U.S. has been concerned with it as a potential bioweapon, thus the contingency plans.