Three studies published Tuesday in
JAMA Internal Medicine
provide new information on the use of tocilizumab against Covid-19.
This monoclonal antibody (marketed by the Roche laboratory under the name Roacterma) is an interleukin inhibitor used in the treatment of autoimmune diseases.
To put it simply, it is believed to calm the immune storm suspected to play a key role in worsening the disease.
The first American study is observational.
She examined nearly 4,500 patients admitted to intensive care.
Physicians observed lower mortality in patients who were administered tocilizumab within 48 hours of admission to intensive care compared to others (27.5% vs. 37.1%).
It remains to be shown that it is the drug that explains this difference and not other biases, potentially numerous in the absence of randomization.
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The other two studies, Italian and French, relate to around 100 serious patients (121 and 131 respectively), of whom approximately half (drawn at random) received tocilizumab after arrival at the hospital (these are then referred to as studies prospective and randomized).
In both cases, they were people who already needed a large supply of oxygen, but neither intubation nor high flow oxygen therapy.
The results are very different: the Italian study saw no beneficial effects to the point of being stopped for "futility";
on the contrary, the French Corimuno-Toci trial, conducted by the AP-HP, finds a 33% reduction in the risk of being admitted to intensive care, and half of being intubated (but no significant influence on mortality, maybe because of the limited staff).
The Roche laboratory unveiled similar results in September for its Empacta trial (with placebo and double-blind), involving 389 patients at a similar stage of severity of the disease: 44% reduction in the risk of admission to intensive care.
A very encouraging result which contrasted with that of Covacta, the 2nd laboratory test which mixed all types of cases and showed no beneficial effects ...
What can we conclude from all this?
That it is too early to make tocilizumab a standard of care in the face of so many discrepancies;
but also that the molecule presents a real potential which justifies the continuation of the tests.
It is interesting to look at what tocilizumab gives in combination with dexamethasone (the corticosteroid identified by the British Recovery trial which constitutes the new global standard of care, in combination with anticoagulants), versus dexamethasone alone.
In France, this is the subject of the Corimuno-Tocidex trial, started this summer in Guyana and extended to around ten hospitals in mainland France.
