Foto: Ronen Zvulun/Reuters
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In brief
- An Israeli hospital reported that a cancer drug appears to be effective against covid-19.
- But the research group is too small to draw conclusions about effectiveness and side effects, says internist-infectiologist Mark de Boer.
- De Boer expects more from rheumatism tocilizumab, possibly in addition to dexamethasone.
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It’s too early to rave about the Israeli drug that may be effective against covid-19. Far too many questions about the research into the drug remain unanswered. That says internist-infectiologist Mark de Boer of the LUMC in Leiden. De Boer is also chairman of the Stichting Werkgroep Antibiotica Beleid (SWAB), which advises Dutch doctors on medication use for covid-19.
The Ichilov Medical Center in Tel Aviv drew a lot of attention last weekend with reports that a still-experimental cancer drug appears to be remarkably effective against covid-19. Thirty patients with moderate to severe symptoms were administered the drug. 29 of them recovered in three to five days. Normally, recovery would take much longer. The drug is called EXO-CD24.
No placebo group
In a response to the report, De Boer points out that the research group of thirty patients is too small to draw far-reaching conclusions about the effectiveness of the drug. Also, as far as is known, the Israeli researchers did not use a placebo group of patients who did not receive the real medicine. That is a requirement to be able to make a good comparison.
‘This is a drug that is still in a very early stage of development,’ says De Boer. According to him, little can be said about the effectiveness and the side effects because the research has not yet been published in a scientific journal. ‘At least I couldn’t find anything,’ says De Boer. ‘That means that we have to be very careful with our expectations.’
Ovarian cancer remedy
The Israeli investigation was led by Professor Nadir Arber, who spoke of a ‘great breakthrough’. Arber originally developed EXO-CD24 as an anti-ovarian cancer agent. Patients should inhale the medicine for a few minutes once a day for five consecutive days.
Reports from Israeli media indicate that the drug fights a dangerous overreaction of the immune system in covid patients. This overreaction is known as the so-called cytokine storm. The Tel Aviv drug uses so-called exosomes to move a protein to the lungs that helps calm the immune system.
Dexamathason used a lot
Doctors worldwide are fighting the cytokine storm mainly through the use of dexamethasone, a proven anti-inflammatory that closely resembles the more famous prednisone. The added value of dexamethasone has been proven in large studies. In addition, there are strong indications that the rheumatism tocilizumab can also help to block an overreaction of the immune system.
That tocilizumab is effective is shown in preliminary findings of a large study in which Utrecht University plays an important role. According to De Boer, this research indicates that the rheumatism medicine offers ‘extra benefits’ if it is used at the right time in addition to dexamethasone.
Different mode of action
A potential benefit for EXO-CD24 is that it has a completely different mode of action. But a new drug like EXO-CD24 shouldn’t just be effective against covid-19. That is not enough. ‘The question is whether a new drug also has added value compared to existing medicines,’ says De Boer.
Numerous companies are currently investigating whether their existing medications are effective in controlling the cytokine storm in covid patients. This also includes the Dutch biotech company Pharming.
