EMA: J&J vaccine possibly linked to rare clots; benefit outweighs risk

Regulatory NewsRegulatory News | 20 April 2021 |  By 

After a review by its safety committee, the European Medicines Agency (EMA) has concluded that a “possible link” exists between receipt of the COVID-19 vaccine from Janssen, the pharmaceutical division of Johnson & Johnson, and a rare combination of blood clots in large veins and low platelet counts.
In a press release and briefing, PRAC, EMA’s safety committee, announced that it judged that the overall benefit-risk profile for the vaccine remains positive but concluded that a warning about the rare combination should be added to product information for the Johnson & Johnson vaccine.
Speaking of the nearly 3,000,000 global deaths from COVID-19, Emer Cooke, EMA’s chief, said “I don’t need to tell you that there is untold human suffering behind all these cases.” At a press briefing at the close of the European business day Tuesday, Cooke added, “Because we have a very good pharmacovigilance program here in Europe,” identification of the potential link will allow regulators and health care providers to spot quickly any additional cases and take appropriate action.
The recommendations and findings PRAC announced now land in the laps of regulators of individual European member states, who will “roll out vaccines based on their national situation,” said Cooke, taking into account such factors as vaccine availability, infection rates, and hospital capacity.
A warning will be added to the vaccine’s product information about the potential for “unusual blood clots with low blood platelets,” according to EMA’s press release. Sabine Strauss, PRAC chair, said no further adjustment of the indications for use is needed. “There is already information that the vaccine should be administered in accordance with local guidelines and local information, so we felt it wasn’t useful” to add further qualification to this “very clear statement,” said Strauss.
The serious combination of clotting and low platelets has been seen in just 8 of the approximately 7,000,000 individuals in the US who have received the Johnson and Johnson vaccine. However, the combination of blood clots in large vessels of the brain or abdomen and thrombocytopenia – low blood platelet counts – is extremely rare and similar to occurrences seen in 287 individuals out of the many millions who have thus far received AstraZeneca’s COVID-19 vaccine. RELATED: ‘Very rare’ thrombotic events with AZ vaccine, concludes EMA's PRAC, Regulatory Focus 09 April 2021)
The two vaccines share an adenovirus vector platform, though the AstraZeneca vaccine is based on a chimpanzee adenovirus and Johnson & Johnson’s on a human adenovirus. The two vaccines also differ in how the spike protein – the means by which the SARS-CoV-2 virus enters human cells – is assembled.
Rollout of the Johnson & Johnson vaccine has been extremely limited in the EU; no cases of the clotting and thrombocytopenia combination have been reported within the European Economic area, regulators reported in the briefing.
Russia’s Sputnik vaccine is also based on an adenovirus platform; in response to questioning, Cooke said that EMA’s review of the Sputnik portfolio “is at an early stage,” so EMA has not yet examined the pharmacovigilance report for Sputnik. However, she said reviewers will be on the alert for any similar potential safety signals for the Sputnik vaccine.
In close questioning, neither Cooke nor Strauss would concede that the cases identified constitute a class effect of adenovirus vector vaccines. However, Strauss characterized what investigators are seeing “at the end of the cascade,” when these patients are identified, as something similar to heparin-induced thrombocytopenia, an immune-mediated syndrome that also involved clotting and bleeding from low platelet counts.
“At the moment, we see that the cases have a lot of similarities – the hypothesis is similar – but it’s too early to draw any conclusions,” said Strauss.


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Tags: coronavirus, EMA, EU

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