The following is a message written by Tom Lloyd, MD, a myositis specialist at the Johns Hopkins Medical Center.

Can Chloroquine Cure Coronavirus?  Not so fast…

In a press conference today, President Trump discussed what the FDA was doing to accelerate approval of treatments for the novel coronavirus, COVID-19.  Chloroquine, a drug that has been used since World War II to treat malaria, was shown in 2005 following the SARS outbreak to slow the spread of the SARS-CoV-1 virus in cultured cells. There are recent studies showing similar results with the related COVID-19 virus, and doctors in China are reporting that chloroquine may be beneficial in hospitalized patients.  Based on this information, Trump announced today that there are “really encouraging early results” and that he thinks chloroquine will be a “game changer”. 

However, as of yet, there is no data that chloroquine is beneficial in treating COVID-19.  While chloroquine is FDA approved for malaria and rheumatoid arthritis, it is NOT FDA approved for use in COVID-19 or any other viral infection.  There ARE ongoing clinical trials of chloroquine in the US and around the world to determine if chloroquine is effective in treating this coronavirus pandemic.  Outside of clinical trials, though, chloroquine is NOT recommended for treating coronavirus at this time.

Even if chloroquine proves to be effective in treating Coronavirus in upcoming months, there are significant potential side effects that inclusion body myositis (IBM) patients should know about. Chloroquine has long been known to have potential nervous system and muscle side effects at high doses.  While the toxic effects on muscle may be reversible in healthy individuals, it’s unknown whether chloroquine might worsen chronic muscle diseases like IBM.  Importantly, chloroquine causes “rimmed vacuoles” on muscle biopsies like those seen in inclusion body myositis, and thus could potentially worsen the disease.  Other reported side effects include allergic reaction, nausea, blurry vision, and headache.

Chloroquine is currently in multiple clinical trials around the globe.  Until we have results of these trials, in my opinion, the risks outweigh the potential benefits in treating coronavirus infections for all patients, especially those with an existing muscle disease.

Tom Lloyd, MD, PhD

Co-Director of the Johns Hopkins Myositis Center

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