With trio of COVID deals, Merck takes a page from its Ebola strategy

Merck’s strategy to tackle COVID-19 appears to echo an approach that allowed the pharma to rapidly develop a vaccine for Ebola -- but on a much faster timeline.

Merck & Co. Inc. (NYSE:MRK) said Tuesday it is expanding its toolbox to fight COVID-19 via a trio of deals that gives the pharma two vaccine candidates and an antiviral therapeutic that could rival Gilead’s remdesivir.

The first deal involves the acquisition of private European vaccine company Themis Bioscience GmbH for an undisclosed cash sum, giving the U.S. pharma rights to Themis’ measles virus vector platform and its preclinical COVID-19 vaccine candidate (see “€40M Round”).

Themis is developing its COVID-19 vaccine candidate with Institut Pasteur, which is the platform’s inventor, and the University of Pittsburgh. Themis’ technology is a live attenuated, replicating measles viral vector that can deliver large genes encoding for antigens directly to macrophages and dendritic cells. Co-founder and CEO Erich Tauber told BioCentury that while no preclinical data is available yet, the expectation is that a live replicating vaccine might provide “a more complete and robust immune response.”

Themis’ COVID-19 program received $4.9 million in initial funding from the Coalition for Epidemic Preparedness Innovations (CEPI), extending the group’s previous support. CEPI had funded the biotech’s vaccine programs against MERS and lassa fever.

Themis and Merck had partnered in August 2019 to develop a vaccine candidate against an undisclosed disease target, with Merck taking an equity stake of undisclosed size in the Austrian biotech.

Tauber said the acquisition should accelerate development of the biotech’s COVID-19 vaccine candidate. He said that while CDMO ABL Europe had been contracted to manufacture clinical supplies of the vaccine, adding Merck provides commercial manufacturing capacity.

“They truly want to make this a global vaccine, and make this available on a global scale,” Tauber said.

In some ways, the Themis deal mirrors the approach Merck took to Ebola. In that case, Merck in-licensed worldwide rights from a small biotech that had no ability to scale global manufacturing -- in that case, NewLink Genetics Corp. -- and in the space of about two years had positive Phase III data. FDA approved that candidate in December as Ervebo to prevent Ebola virus infection (see “Crushing Need”).

But like some other players in the COVID vaccine arena, Merck isn’t relying on a single vaccine modality.

Also on Tuesday, Merck partnered with non-profit IAVI to develop an rVSV-based COVID-19 vaccine candidate. The recombinant vesicular stomatitis virus (rVSV) technology was the same platform Merck used to develop Ervebo.

IAVI has used the same rVSV platform as the basis for four other vaccine candidates, including an HIV candidate.

HHS’s Biomedical Advanced Research and Development Authority (BARDA) is providing $38 million in early development funding for the rVSV candidate.

Beyond Merck Chairman and CEO Kenneth Frazier being at the helm for both deals, there are other tie-ins to Merck’s Ebola program and its COVID-19 approach. IAVI’s President and CEO Mark Feinberg was VP of Merck Vaccines during Ervebo’s development.

Both vaccine candidates are due to enter the clinic this year.

The deals come as Merck had already been active in COVID-19 consortia: the Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV) and COVID-19 Therapeutics Accelerator (see “Collaborating to Clobber COVID-19”).

However, one remaining question is how Merck would allocate manufacturing capacity between the two different vaccine candidates.

Outside of COVID-19, Themis’ lead program is MV-CHIK, a vaccine to prevent Chikungunya infection that has completed Phase II testing. Tauber said the company has also started some preclinical work in applying its measles vector in cancer settings.

Themis had raised at least $75.5 million in venture financings from investors such as Wellington Partners, Ventech, Omnes Capital and Global Health Investment Fund, among others.

Merck in-licenses antiviral

Beyond the vaccines, Merck also brought in an antiviral that could rival remdesivir from Gilead Sciences Inc. (NASDAQ:GILD) -- or provide efficacy in resistant patients.

Merck obtained exclusive, worldwide rights to EIDD-2801 from Ridgeback Biotherapeutics LP to treat COVID-19. The nucleoside analog that blocks replication of RNA viruses is in a Phase I trial. Ridgeback, which in March licensed the program from an affiliate of Emory University, will receive an undisclosed upfront payment and is eligible for milestones and royalties.

Preclinical data published in Science Translational Medicine last month showed that EIDD-2801 has broad antiviral activity against SARS, MERS and SARS-CoV-2, as well as other coronaviruses. In vitro assays showed the nucleoside inhibitor had an IC50 of 0.3 uM.

The candidate also showed increased potency against coronaviruses that have resistance mutations to remdesivir (see “UNC Data for Emory Compound”).

In addition, the orally available therapy could be used in earlier treatment settings such as in-home, whereas IV remdesivir has to be administered in hospitals.

Merck said it expects to make its vaccines and antivirals for COVID-19 “accessible and affordable globally.”

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