French institute aims to start human trials of ‘promising’ Covid-19 drug this winter

A bust of Louis Pasteur, the 19th century French scientist, outside the Pasteur Institute in Lille.
A bust of Louis Pasteur, the 19th century French scientist, outside the Pasteur Institute in Lille. © Denis Charlet, AFP

The Pasteur Institute in the northern French city of Lille has confirmed the discovery of a “very promising” drug in the fight against the coronavirus pandemic, without naming it. FRANCE 24 spoke to the institute's director-general about the potential new treatment ahead of the first clinical trials.

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Hope in the time of Covid-19. As infection rates climb in many European countries, including France, the Pasteur Institute in Lille recently confirmed the discovery in June of a drug molecule that has shown promise as a therapeutic treatment against the virus.

Like hydroxychloroquine — which was controversially touted as a possible treatment early on in the pandemic — it is not a new medicine, but one that has been used in the past to treat other conditions. It’s name has been kept a closely guarded secret, largely to avoid the same media frenzy that surrounded hydroxychloroquine, before it was largely discredited. 

The unnamed drug has already undergone a number of laboratory studies, which found that it demonstrated “considerable power against the virus”, according to Dr. Benoît Deprez, scientific director of the Pasteur Institute in Lille.

The drug is expected to begin early clinical trials — which could cost an estimated €5 million — this winter, before being approved for use in patients with confirmed Covid-19 diagnoses. FRANCE 24 spoke with the director-general of the Pasteur Institute in Lille, Dr. Xavier Nassif, about the research centre’s potential “discovery”.

FRANCE 24: Can you explain a little about the drug discovered by the Pasteur Institute?

Dr. Xavier Nassif: It was discovered through drug repositioning [editor's note: when a laboratory investigates whether an existing medicine can be used for new therapeutic purposes]. We had the opportunity to access a bank of 2,000 drug molecules at the beginning of the pandemic. These 2,000 molecules were then repurposed. Many were identified as active, but at fairly high doses compared with the rates at which they could be used. 

The molecule that stood out is not only active, but more importantly capable of blocking the virus from replicating in cells at rates compatible with normal human use. What’s more, this drug, which has been in use for years, has very few side effects and is generally well tolerated — which makes it a strong candidate. Further laboratory studies have shown that it blocks the virus from replicating in several types of cells, including in primitive human pulmonary cells. 

All of these tests were done in vitro — or in a laboratory — so we’re being cautious, because we still have to confirm the medicine’s efficiency in vivo, meaning whether the molecule is capable of blocking replication as efficiently in humans.  

Does this discovery represent a serious hope in the fight against coronavirus?

If we show that this molecule can block viral replication in humans, it is ready for immediate use. It’s a drug with several characteristics: it’s already been given to humans without too many side effects, and it can be administered enterally [or through the digestive tract], instead of through subcutaneous or intravenous routes. Clinical trials will tell us what are the best indications for use.

This would prevent subjects from becoming severely ill once infected. It could also prevent those who come into contact with the subject from becoming carriers of the virus. The drug, when given to asymptomatic patients, could also prevent them from secreting the virus over long periods of time, therefore reducing quarantine. The results of these clinical trials will help us to determine the exact uses of the drug and the eventual impact on how the epidemic is managed.

If the clinical trials are a success, will it be possible to mass produce the drug at low cost?

The molecule we’re talking about isn’t very expensive. It will be up to the manufacturer to see what can be done. We’ve already contacted them to let them know about our discovery. They are very helpful, very cooperative, and I think that the maximum will be done to make this medicine available. In the event that this drug is very efficient and needs to be distributed on a mass scale, measures should be taken at the manufacturing level to respond to the demand.

Will you publish the results of your clinical trials in a scientific journal? 

Of course we will. First, we’re going to try to demonstrate the drug’s efficacy in vivo using a macaque monkey as a test subject. If successful, we will of course publish the results. We’re impatient to start animal trials. If all goes well, they should begin in November.

Afterwards, we hope to begin human trials this winter, once we have the necessary authorisations. It’s likely that success using monkeys will speed up the possibility of progressing to human trials.

What is needed before you can start clinical trials?

Clinical trials are expensive. We hope that the communication surrounding our discovery will help us to raise funds from both public and/or private donors. Right now, what we need is money.

This article was adapted from the original in French by Rachel Holman.

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