October 27, 2020

Antibody treatments are promising—but there's 3 key reasons to be cautious of the hype

Daily Briefing

    Antibody treatments for Covid-19 have shown promising results in early clinical trials, but the treatments likely will be in short supply if they're authorized for use in the United States, leading to questions about where and how the limited supply of treatments should be allocated. 

    What are antibody treatments—and are they effective?

    Researchers and drug companies around the world are testing the use of antibody therapies to treat and prevent Covid-19, the disease caused by the novel coronavirus. Antibody therapies are created using antibodies that were naturally generated by either a human or animal infected with a given disease or virus. For Covid-19 antibody therapies, the treatments rely on isolated antibodies to neutralize the new coronavirus, known as SARS-CoV-2.

    Researchers also are developing monoclonal antibodies, which are antibodies that can be isolated and manufactured in larger quantities via artificial reproduction, for the novel coronavirus.

    Antibody treatments for Covid-19 have been in the spotlight in recent weeks, after President Trump credited an experimental antibody treatment developed by Regeneron for his Covid-19 recovery.

    Earlier this month, Eli Lilly and Regeneron separately announced that they've applied for emergency use authorizations (EUAs) from FDA for their experimental antibody treatments for Covid-19. In addition, HHS earlier this month announced that it had reached a $486 million agreement with AstraZeneca to develop and secure supplies of up to 100,000 doses of its experimental antibody cocktail aimed at preventing or treating novel coronavirus infections.

    Some early clinical trials have shown that antibody therapies could help to treat patients with Covid-19. For instance, Eli Lilly last month announced the interim results of a Phase 2 study that found its antibody drug lowered hospitalization rates of mildly and moderately ill Covid-19 patients when compared with a placebo.

    But Eli Lilly on Monday announced that it will end its U.S.-based clinical trial testing its antibody treatment in hospitalized patients with Covid-19, because data indicated that the treatment is not likely to have a clinical benefit in helping patients recover from advanced stages of the disease. Eli Lilly said it will continue clinical trials testing the antibody treatment in patients with mild and moderate cases of Covid-19, as well as trials testing whether the treatment can prevent SARS-CoV-2 infections. Based on data from those trials, the company said it is "confident" its antibody therapy can help to prevent the progression of Covid-19 in people in early stages of the disease.

    Antibody treatments will likely be in short supply

    Although antibody therapies may show promise for helping some patients with Covid-19, experts warn that the therapies probably will have a limited effect on addressing America's Covid-19 epidemic, because the therapies likely will be in short supply.

    Regeneron has said that it could have about 50,000 doses of its antibody treatment available within the coming weeks, and about 300,000 doses ready by the end of this year. Meanwhile, Eli Lilly has said it could have 100,000 doses of its antibody treatment available within the coming weeks, and the company plans to have about one million doses available by the end of this year. And AstraZeneca, which hasn't yet sought an EUA from FDA for its antibody treatment, has estimated that 100,000 doses of its therapy could be available by the end of this year.

    But those supplies likely will fall far short of demand in the United States, as the country's coronavirus epidemic is surging in many states. Currently, around 70,000 Americans are testing positive for the virus each day, meaning initial supplies of the antibody treatments could be used up quickly.

    Further complicating the matter, experts say, is that the dosages of antibody treatments needed to prevent Covid-19 in people who've been exposed to the virus are different than the dosages need to treat Covid-19 in patients who already are infected. In addition, the therapies must be administered intravenously in a hospital or clinic, and they must be shipped in temperature-controlled trucks and carefully handled.

    Taking all of those complexities into consideration, experts are raising questions about how the treatments will and should be distributed.

    How do we equitably distribute treatments?

    In some instances, companies' initial doses of their antibody treatments will be given to the federal government, which then will distribute the therapies so they can be used to treat Americans.

    Federal officials have said that, once those stores have been depleted and Covid-19 treatments and vaccines are available on the market, states will be in charge of allocating available doses of antibody treatments. However, many states have been overwhelmed by recent spikes in new coronavirus cases and haven't yet made a plan for allocating treatments or vaccines—and the available guidelines do not always align, the New York Times reports.

    For instance, Douglas White, a medical ethicist and professor of critical care medicine at the University of Pittsburgh School of Medicine, pointed to guidelines he wrote for distributing remdesivir, an experimental Covid-19 treatment that also was in short supply earlier this year.

    The guidelines, which Pennsylvania used to distribute the drug, recommend that people from economically disadvantaged communities receive priority access for treatment, as they're at a higher risk of dying from Covid-19.

    However, Jewel Mullen, associate dean for health equity at the University of Texas' Dell Medical School, recommended that hospitals use the same guidelines that she helped to develop for the National Academies of Sciences, Engineering, and Medicine on distributing a potential vaccine against the novel coronavirus. These guidelines would give health care workers and first responders top priority, "because we need them to be well," Mullen said. "They're protecting us all the time. They're putting themselves at risk all the time."

    After that, Mullen said the antibody treatments should go to the most vulnerable patients first, with the goal of keeping them out of the hospital. "Maximize the benefit, make sure everyone is valued and thought about equally and address health inequities," Mullen said.

    But despite the best laid plans, Erin Fox, a pharmacist at the University of Utah, said if demand for the new antibody treatments is greater than supply, it could be difficult for hospitals to follow an equitable rubric for distribution. "If the amount that we get is so small, it's probably very likely that we would just use it for a short period of time … and just use it up and not try to make some very difficult rationing decisions" (Thomas, New York Times, 10/20; Johnson, Washington Post, 9/30; Harris, "Shots," NPR, 10/21; Gross, Forbes, 10/26; Romo, NPR, 10/26; Loftus, Wall Street Journal, 10/26).

     

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