Hydroxychloroquine trial for COVID-19 fizzles out

NCT ID NCT04333654

Terminated Disease control Sponsor: Sanofi Source: ClinicalTrials.gov ↗

First seen Jun 26, 2026 · Last updated Jun 26, 2026

Summary

This early-phase study tested whether hydroxychloroquine, a drug used for malaria and autoimmune diseases, could reduce the amount of virus in adults with mild COVID-19 not needing oxygen. Only 8 people took part before the trial was stopped early. The study was too small to draw any meaningful conclusions about the drug's effect.

What this could mean

Our plain-language read of the trial. This is informational only — not medical advice or a prediction.

Active substance: hydroxychloroquine (Plaquenil)
What this could lead to: If it had worked, this could have pointed toward a treatment to reduce the amount of virus in people with mild COVID-19.
What could go wrong: This was a very small, early-phase trial that was terminated early, so results are not reliable. Hydroxychloroquine has not been proven effective for COVID-19 and can have serious side effects.

This is an AI summary of the original study and may miss details. Read our disclaimer.

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Conditions

The condition(s) this trial relates to.

Coronavinae infectious disease COVID-19

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

CORONAVIRUS INFECTION

Contacts and locations

Locations

Investigational Site Number 0561001

Brussels, BE-1200, Belgium
Investigational Site Number 0561002

Lodelinsart, 6042, Belgium
Investigational Site Number 2501001

Bordeaux, 33076, France
Investigational Site Number 2501002

Paris, 75005, France
Investigational Site Number 5281001

Groningen, 9728 NZ, Netherlands
Investigational Site Number 5281002

Harderwijk, 3844 DG, Netherlands
Investigational Site Number 8400001

Boston, Massachusetts, 02115, United States

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