An influential study measuring the efficacy and risks of the antimalarial drug hydroxychloroquine as a treatment for COVID-19 has been retracted at the request of its authors. It was published last month in prominent medical journal The Lancet.

The authors asked for the retraction because, after questions were raised about the data used in the research, independent auditors were denied access to the information required to verify that data. The study utilized data from a privately held healthcare analytics company, Surgisphere, which turned away the auditors.

Coronavirus in close-up.

Image source: Getty Images.

The study's authors said that their analysis of the data showed that  hydroxychloroquine use by COVID-19 patients led to a higher risk of serious side effects or death. This finding had a major impact, shifting the medical community's hopes away from the drug as a potential treatment for the disease caused by the SARS-CoV-2 coronavirus.

Based on that analysis, the World Health Organization (WHO) briefly halted clinical trials it was conducting on hydroxychloroquine. Subsequently, multinational pharmaceutical company Sanofi (NASDAQ:SNY) stopped supplying it for patients participating in its own trials.

In a retraction published in The Lancet, the study's authors wrote: "We can never forget the responsibility we have as researchers to scrupulously ensure that we rely on data sources that adhere to our high standards. Based on this development, we can no longer vouch for the veracity of the primary data sources."

Sanofi hasn't commented on the retraction. The company continues to be active particularly in the hunt for a COVID-19 vaccine. It is leveraging its considerable vaccine development experience in collaboration with U.S. government health authorities in a program aimed at preventing the disease.

On Friday, Sanofi's shares inched up by 0.3%, well behind the gains of the broader stock market.