Coronavirus Treatment Updates

The updates here cover developments since my last post on May 24th, which I updated on June 4th to reflect two study retractions related to hydroxychloroquine.

Remdesivir

Before June, we already had two randomized trials – one from Gilead, the manufacturer, and one from the NIH – showing that Remdesivir was an effective treatment for patients with severe COVID-19. At the beginning of this month, Gilead announced results from another trial of patients categorized as having moderate COVID-19 symptoms. See the results here. In short, Remdesivir works decently well for those patients too. It doesn’t immediately cure them, but it does make them more likely to recover faster. The treatment group, with 384 patients, had a lower mortality rate than the control group. Death is so rare, even for COVID-19 patients in a hospital, that it takes a giant sample size to be confident if a lower mortality rate is due to random chance. This study wasn’t designed for that purpose, so the sample size was too small. Still, all three of the randomized trials of remdesivir have found lower mortality rates, so if one or two more come out we may have enough data to pool the results and say for sure if this treatment lowers fatality rates. Given that we’re very confident it helps people recover from symptoms faster, it doesn’t seem like a giant leap to expect it will reduce mortality.

Dexamethasone

I admit this was a treatment I hadn’t even heard of until a trial came out proving it reduced COVID-19 fatality rates. See the results in Oxford’s press release here. This trial enrolled 6,425 patients, making it large enough to get a strong signal for whether the drug reduces COVID deaths. The trial split people into three severity groups: people needing a ventilator, oxygen, or no respiratory support.

People in the severe group were 35% less likely to die with dexamethasone and those in the oxygen group were 20% less likely to die. People who didn’t need oxygen didn’t benefit from the drug.

Convalescent Plasma

We finally have a randomized trial of convalescent plasma. Previous studies were promising, but weren’t randomized. This new randomized trial published in JAMA by a group of scientists mostly from Wuhan enrolled 103 patients. The study ended early because they ran out of patients.

The basic mechanism for convalescent plasma is that they’re giving your body antibodies to fight off the virus. This study very strongly backs up that the mechanism worked: 72 hours after transfusion 87% of people in the treatment group tested negative for the virus versus 37% in the control group. But, whereas people with “severe” symptoms did recover faster after transfusion, people in the even more dire “life threatening” category didn’t. That lines up with prior results from a Mount Sinai study that found the sickest patients benefited less.

Hydroxychloroquine

Probably no one will learn this from my blog, but the FDA pulled its emergency use authorization for HCQ. There’s no compelling evidence of benefit of the drug for COVID-19, but it does cause heart problems. And on Saturday the NIH announced that it was stopping a clinical trial of HCQ just a little early because interim from 470 of 500 planned patients showed no benefit for the drug. There may be other trials ongoing, so it’s conceivable more positive results could come out, but it’s very unlikely.

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