Merck claims first-ever FDA approval for an Ebola vaccine

Merck & Co’s Ebola vaccine Ervebo has been cleared for marketing in the US, just weeks after getting a world-first regulatory approval in Europe.

Originally developed by NewLink Genetics, Ervebo – which was previously known as V920 or rVSVΔG-ZEBOV-GP – has been approved by the FDA to prevent disease caused by the Zaire strain of the Ebola virus in adults.

That is the variant of the virus that is responsible for the current outbreak in the Democratic Republic of the Congo (DRC), which has killed 2,211 people out of 3,351 cases as of 18 December, according to the World Health Organization (WHO).

The FDA approval of Ervebo comes shortly after another Ebola vaccine developed by Johnson & Johnson and Bavarian Nordic, known as Ad26.ZEBOV/MVA-BN-Filo, was filed for approval in Europe. Meanwhile, two Ebola vaccines developed by GlaxoSmithKline were handed over to the US Sabin Vaccine Institute for further development in August.

Cases of Ebola are vanishingly rare in the US, and have generally been seen in individuals who travel to other countries, particularly health care workers who can become ill after treating patients with the infection, says the FDA.

Prior to the FDA and EMA approvals Ervebo had already been approved for use in emergencies by the WHO, based on trials conducted during that epidemic which suggested it had a protective efficacy rate of 93%.

The disease is highly contagious, and is transmitted through direct contact with blood, body fluids and tissues of infected wild animals or people, as well as with contaminated surfaces and materials like bedding and clothing.

Symptoms are initially flu-like but escalate rapidly to include vomiting, diarrhoea, rash, impaired kidney and liver function and in severe cases internal and external bleeding. The worst outbreak – in West Africa in 2014-2016 – resulted in more than 11,000 deaths.

Around 16,000 people have also received Ervebo in clinical trials in Africa, Europe and the US, and Merck has been setting up production at a new facility in Germany that should become available in the third quarter of 2020 to provide commercial supplies.

In the meantime, the company has said it will continue to provide the shot to compassionate-use programmes in Africa. It is expected that Merck will win orders for the vaccine from governments and other organisations seeking to lay in stockpiles of the vaccine to battle future outbreaks.

Earlier this month, the Gavi vaccine alliance approved $178 million in funding through 2025 to build up global stores of Ervebo.

Low- and middle-income countries will be able to access the stockpile free of charge, while wealthier countries will be able to access vaccines but will be expected to pay.

Another Keytruda approval

Meanwhile, the FDA approval of Ervebo was the second bit of good news for Merck in the US this week, coming after its cancer immunotherapy Keytruda (pembrolizumab) was backed by an FDA advisory committee as a treatment for  high-risk, non-muscle invasive bladder cancer (NMIBC).

Keytruda is up for an FDA verdict next month for the 30% to 40% of NMIBC patients who don’t respond to standard treatment with BCG injections, as an alternative to chemotherapy or surgery to remove the bladder.

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