Remdesivir’s Early Trial Data Necessitates Guarded Optimism

By Ruchi Jhonsa, Ph.D.

As the world waits for a cure to the novel coronavirus, a promising yet limited study has shown the effectiveness of Gilead’s broad-spectrum antiviral drug remdesivir on 53 patients receiving the drug on compassionate use basis.

Gilead Sciences has announced a preliminary cohort analysis of a study that evaluated remdesivir’s performance in patients by quantifying rates of key clinical events, changes in oxygen support requirements, hospital discharge and other side effects leading to discontinuation of the treatment. Over 18 days, 17 of the 30 patients got off mechanical ventilation and almost half of the patients studied were ultimately discharged. However, the improvement was mostly restricted to patients who were on noninvasive ventilation and less than 70 years of age. The overall mortality of 13% was seen in this cohort with the highest mortality observed in patients who were on the ventilator.

The majority of the patients enrolled were males over 60 years of age with preexisting conditions including hypertension, diabetes, hyperlipidemia, and asthma in the United States, Europe, Canada, and Japan. While most of them continued the full 10- day treatment, four patients from the group exited prematurely due to the worsening of pre-existing conditions and elevation of liver enzymes.

The report is published in the latest issue of New England Journal of Medicine. Although the data looks promising, it has its limitations, which makes the effectiveness of the drug difficult to believe. Compassionate use data comes from a small group of patients who were followed for a relatively short period of time without comparison to a randomized control group. All of which makes it difficult to “draw definitive conclusions” about the effectiveness of the drug, said the lead author of the publication Jonathan Grein, director of hospital epidemiology at Cedars-Sinai Medical Center in Los Angeles.

This uncertainty and confusion in the data also resonated with many scientists. Stephen Evans, a professor of pharmacoepidemiology at the London School of Hygiene and Tropical Medicine said, “The data from this paper are almost uninterpretable. There is some evidence suggesting efficacy, but we simply do not know what would have happened to these patients had they not been given the drug.”

Currently, what needs to be determined is in which patients does the drug show activity, how long should the treatment be given and what stage of the disease would the treatment be most effective? “Many answers are needed, which is why we need multiple types of studies involving many types of patients,” said Daniel O’Day, Gilead’s chairman and chief executive officer. To answer these questions, clinical trials are underway in China and the U.S. studying the effect of antiviral on a large cohort of patients. Some of these answers will be revealed in the coming weeks with the release of initial data from the various clinical trials.

Mixed Reactions

Remdesivir was touted as the most promising drug by WHO based on existing human and animal data. This raised hopes amongst people that after all, the first treatment for the novel coronavirus may be out soon. However, earlier this week Gilead announced major mid-study changes in its global trials by adding patients on ventilation in the cohort and changing the primary endpoint of the trial. Such a move could mean that the studies failed to detect the improvements associated with remdesivir. But the addition of mechanically ventilated patients to the study group could also reflect towards the drug’s positive effect on patients. Meanwhile, as the company has ramped up production, it is not clear what the future beholds for the drug.

Related Article: Chugai Initiates Actemra’s Phase 3 COVID-19 Trials in Japan

References

1. https://www.gilead.com/news-and-press/press-room/press-releases/2020/4/data-on-53-patients-treated-with-investigational-antiviral-remdesivir-through-the-compassionate-use-program-published-in-new-england-journal-of-medici

Author

Ruchi Jhonsa