Why You Should Be Skeptical of Early Results of COVID-19 Drug

  • A leaked report on preliminary clinical trial results suggests that an experimental drug may work against COVID-19.
  • But experts caution against reading too much into this.
  • The leaked report is anecdotal, meaning it can’t be used to show whether the drug is safe or effective.

Patients with severe COVID-19 receiving an experimental drug called remdesivir saw rapid improvements in fever and respiratory symptoms, with most patients going home from the hospital in less than a week, according to a video obtained by STAT News last week.

The patients were taking part in a clinical trial of the drug at the University of Chicago. Of 113 trial participants who received daily infusions of remdesivir, the majority left the hospital after 6 days of treatment, with few deaths.

“The best news is that most of our patients have already been discharged, which is great. We’ve only had two patients perish,” Dr. Kathleen Mullane, an infectious disease specialist at the University of Chicago who’s leading the clinical trial, said in the video.

With no approved treatment specific for COVID-19 — and no vaccine against the virus that causes it — this report has already raised hopes that a treatment is just over the horizon.

The stock of Gilead, the drug’s manufacturer, rose 12 percent on Friday in response to the news, reports CNN.

Another study posted April 15 on the preprint server bioRxiv found that remdesivir worked on a monkey model of COVID-19. This study, though, has not been peer-reviewed, so the results are preliminary.

Experts caution against reading too much into the University of Chicago report. This is one site of many taking part in the study.

So, until the full data is available, the leaked report is anecdotal, meaning it can’t be used to show whether the drug is safe or effective.

“Hearing about the good outcomes coming out of the University of Chicago are encouraging, but we cannot draw conclusions without actually seeing all of the analyzed data from the clinical trials, from all of the centers worldwide,” wrote infectious diseases physician Dr. Kevin A. Grimes and infectious disease pharmacist Katherine K. Perez, PharmD, in an email to Healthline.

Experts urge caution around leaked results

Grimes and Perez are the lead investigators on two phase III clinical trials at Houston Methodist Hospital in Texas, which are evaluating remdesivir as a treatment for COVID-19.

There are many similar trials going on around the world. STAT News reported that Gilead’s study of severe COVID-19 includes 2,400 participants from 152 clinical trial sites. Its study of moderate COVID-19 includes 1,600 participants from 169 sites.

A Gilead spokesperson told Healthline in an email that the data from all of these sites will need to be analyzed in order to draw any conclusions from the study.

“Anecdotal reports, while encouraging, do not provide the statistical power necessary to determine the safety and efficacy profile of remdesivir as a treatment for COVID-19,” he said.

Caution is especially needed because scientists still don’t fully understand how COVID-19 progresses in different groups of people with the disease.

“There needs to be more evidence that it is actually remdesivir that is driving these outcomes rather than some other factors,” said Dr. Bruce Y. Lee, a professor at the CUNY Graduate School of Public Health & Health Policy.

“For example, would patients who received the medication have been likely to get better even without the medication? Or are patients improving simply because they are getting more attention from healthcare professionals?”

Lee points out there have been many cases where “promising” early results didn’t hold up when additional studies were later done.

The Food and Drug Administration (FDA) reports that only 25 to 30 percent of drugs get through phase III clinical studies, which is the stage where remdesivir is right now.

“That’s why unpublished, leaked data can potentially be misleading,” Lee said. “Also, you can’t tell how well everything was done, including the analyses, until we have more information.”

Before new drugs can be approved, study data has to be reviewed by the FDA to see how well the data was collected or analyzed during the study.

Without this, potentially dangerous — or useless — drugs could end up on the market.

Long road to approval of new drugs

The Gilead study compares 5- and 10-day treatment courses of remdesivir. The main goal is to see whether one treatment works better at improving outcomes in COVID-19 patients.

Some experts have raised concerns that there’s no placebo, or a group of people who don’t receive the treatment.

Most studies of new drugs compare people taking the drug with those in the placebo group. However, this isn’t always possible in the middle of a pandemic.

“It would be extremely difficult for clinicians to agree to randomize patients into a placebo arm and withhold other investigational therapies that have potential benefit for their patients,” Grimes and Perez said.

They add there are ways to statistically adjust for the lack of a placebo group.

For example, a number of COVID-19 studies have been published that show the clinical course of people not receiving remdesivir. These results could be used as a stand-in placebo group.

There are also concerns about the way in which the University of Chicago report was released, especially since Gilead’s stock price rose after the leaked report.

On Friday, Democratic Rep. Lloyd Doggett of Texas called for the Securities and Exchange Commission to investigate the leak of the video under federal securities law.

In spite of the early release of the report, real results may be coming along soon.

According to STAT News, the University of Chicago’s Mullane expects the study site’s data to be “locked” by Gilead soon. This happens before analysis of the data begins.

There’s no indication, though, of when the other sites will be finished collecting their data.

If the data still look promising after analysis, Gilead would have to apply to the FDA for approval. Even with an expedited process, this could take months.

Which is why Lee urges caution when looking at any preliminary results.

“We’ve seen a number of examples during this COVID-19 pandemic where initial information, data, and insights proved to be premature,” he said. “Premature leakages can offer false hopes and alter behavior in the wrong direction.”

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