Yesterday the Food and Drug Administration released a clinical memorandum giving Emergency Use Authorization for COVID-19 Convalescent Plasma (CCP) therapy, a previously unapproved biological product. For several months clinicians treating severely ill COVID-19 patients have transfused plasma donated by convalescing COVID-19 patients, rich with the antibodies to the virus produced by their immune system, hoping that these same antibodies can help patients suffering from active infection. Early results have been promising but, as some critics of the FDA decision have stated, more data is needed before definitive conclusions can be drawn regarding the efficacy of CCP therapy.
Using the antibodies in plasma from patients who have defeated a viral infection to treat newly infected patients is not a new idea. Clinicians and clinical researchers used it as early as the late nineteenth century to treat diphtheria and it was employed in the early twentieth century in the Spanish influenza epidemic.
By issuing the EUA allowing physicians to use convalescent plasma, the FDA didn’t make a final determination as to the treatment’s efficacy. The agency stated it “may be effective.” Importantly, it concluded that the treatment is safe. The FDA press release stated, “the known and potential benefits of the product outweigh the known and potential risks of the product.” (emphasis added)
The FDA usually requires proof of efficacy before approving a treatment, and that can add several years to the approval process. This wasn’t always the case. Until 1962, when Congress passed the Kefauver‐Harris Amendment to the Food, Drug, and Cosmetic Act of 1938, the FDA’s sole mission was to assure a drug’s safety. Adding the requirement that a pharmaceutical manufacturer prove a drug’s efficacy for the treatment of a specific condition can add several years to the approval process, long after the safety of the drug has been established. Patients in the U.S. sometimes wait years for a drug that is already approved to treat their condition in other developed countries to become available for them. Frustration with this fact led Congress to pass the “Right to Try Act” in 2018.
Once a therapy has passed the FDA’s efficacy requirements and clinicians are permitted to use it, the FDA still monitors its use going forward in case it needs to reassess its efficacy. And the FDA permits clinicians to use the approved drug to treat any other conditions for which they judge it may be useful. That’s called “off‐label” use, because the label is only allowed to state the condition for which the FDA approved its use. The antimalarial and rheumatoid arthritis drug hydroxychloroquine has received much publicity—and been the subject of much controversy—for its off‐label use to treat COVID.
This is ironic because the FDA makes doctors and patients wait, sometimes, up to twelve years before it allows them to use a drug for the treatment of condition “A,” but once it is approved to treat that condition, it trusts the judgement of clinicians and clinical researchers (who are constantly conducting and reporting on observational as well as randomized controlled trials) to use the drug to treat conditions “B” through “Z.” What’s more, it still requires updates on the drug’s efficacy for treating condition “A” even after it is approved.
Yesterday’s EUA leaves decisions about CCP’s efficacy up to doctors and clinical researchers, instead of making them wait until the FDA’s bureaucrats are fully convinced. It should do this all of the time, not just during a public health emergency. To patients with life‐threatening or debilitating conditions, every passing moment is an emergency.
