In the race to stop mpox, GeoVax prepares for a marathonIn the race to stop mpox, GeoVax prepares for a marathon

After mpox – formerly known as monkeypox – emerged in Western and Central Africa in 2023, medical organizations worldwide have sought to mitigate the impact of the disease by fast-tracking vaccines and other treatments to the affected regions facing what has become a deadly epidemic.

Bavarian Nordic arrived as an early leader in supplying vaccines. The firm worked with Gavi, the Vaccine Alliance in 2024 to send 500,000 doses of its MVA-BN vaccine to Africa last year. And last week, KM Biologics announced the distribution of 50,000 doses of mpox vaccine to the Democratic Republic of the Congo.

With the war against mpox raging on, John Sharkey, VP of business development at vaccine maker GeoVax, spoke to BioProcess Insider about his company’s own mission, the challenges presented by the mpox epidemic, and the work his organization is doing to develop, manufacture, and distribute vaccines.

GeoVax has two mpox-vaccine programs in development, called GEO-MVA and GEO-CM04S1. Sharkey said, “The company acquired rights from the US National Institute of Health (NIH) to develop and commercialize MVA for use as a vaccine against mpox and smallpox. Based on guidance received from regulators and leveraging the recognized safety of MVA, the company is pursuing an expedited registration pathway to bring GEO-MVA to market.”

Although it is being developed specifically for mpox and smallpox, Sharkey said that GEO-MVA is expected to work for other orthopox viruses as well.

He added that such MVA vaccines are preferred by the World Health Organization (WHO) for certain vulnerable populations such as pregnant and lactating women, people who are immunocompromised, and children.

Bavarian Nordic’s MVA-BN vaccine fits that criterion, but to meet the needs of the African continent, more companies such as GeoVax seek to do their part. “African health authorities have requested 20 million doses of vaccines but only 2–5 million are expected to be available by the end of 2025,” Sharkey said.

“The complicated manufacturing process for MVA remains a significant impediment to manufacture on demand as well as for the establishment of local/regional manufacturing capacity. GeoVax has initiated efforts to both increase the availability of MVA vaccine supply in the near term with the development of GEO-MVA.”

GeoVax’s second vaccine candidate for mpox is being developed first as a next-generation COVID-19 vaccine but has shown effectiveness toward mpox as well. GEO-CM04S1 incorporates sequences from both the spike (S) and nucleocapsid (N) proteins. “By targeting two major components of on the SARS-CoV-2 virus, GEO-CM04S1 appears to elicit a broader, more robust immune response compared to currently approved mRNA vaccines," Sharkey said.

Manufacturing MVA vaccines

“As a vaccine vector, MVA offers some significant advantages over other platforms,” Sharkey said, citing its safety, temperature stability, large coding capacity, and ability to code for multiple antigens of interest.

He expressed hope that the first regulatory dossier submission for GEO-MVA manufactured with the chicken embryo fibroblast (CEF) platform will be achieved by early 2027. With the help of contract development and manufacturing organization (CDMO) Oxford Biomedica (OXB), the company has manufactured materials to support Phase III clinical trials expected to take place later this year.

But traditional MVA manufacturing processes using CEFs has several drawbacks. The virus does not replicate in mammalian cells, and the specific pathogen free (SPF) eggs required to obtain cells are not readily available and require operators with specialized skills in aseptic techniques.

GeoVax recently announced a licensing collaboration with ProBioGen AG (Berlin) to utilize their continuous duck cell line, AGE.1, for the manufacture of the company's MVA vaccines, including GEO-MVA and GEO-CM04S1. 

Sharkey said, “As a suspension cell line, AGE.1 is well suited for the manufacture of MVA as it is highly productive, approximately 10-fold better than seen with CEFs and as a suspension cell line can be processed in standard manufacturing equipment. As a continuous cell line, the material can be prepared, characterized, and frozen prior to being needed for a manufacturing run. We believe with the implementation of the AGE.1 manufacturing platform, significantly lower unit costs, increased yield and manufacturing site flexibility can be readily achieved.”

He added, “Longer term, we believe the transition to a next-generation manufacturing platform, utilizing the AGE.1 suspension cell line, is the best solution to address MVA manufacturing bottlenecks.”

In the meantime, the organization is working with WHO, the Africa Centres for Disease Control and Prevention (Africa CDC), and the Coalition for Epidemic Preparedness Innovations (CEPI) to plan for how best to address both current and future viral outbreaks.