The coronavirus pandemic has inspired numerous clinical trials to test potential treatments for people infected with the virus. Cancer patients have an elevated risk of severe outcomes from COVID-19, so finding ways to better treat the disease in these patients could be especially beneficial. Yet information from clinical trials on treatments that might help cancer patients is lacking. Many clinical trials of COVID-19 treatments exclude people with cancer or people who are taking certain cancer drugs or are immunosuppressed. Even when trials do include cancer patients, they don’t always report their outcomes separately.

In the absence of clear evidence about which drugs would work best for cancer patients with COVID-19, doctors have often given the same drugs to cancer patients as to the general population. In the early months of the pandemic, treatment often included corticosteroids, hydroxychloroquine or remdesivir.

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​To understand whether these drugs were effective, Jeremy L. Warner, a medical oncologist and hematologist at Vanderbilt University Medical Center in Nashville, Tennessee, and his colleagues analyzed the records of more than 2,000 Americans with cancer who had also been diagnosed with COVID-19 for a paper published in the October 2020 issue of Cancer Discovery. The researchers collected their data via the COVID-19 and Cancer Consortium (CCC19), a group that now includes more than 120 cancer centers and other organizations that share data on their cancer patients with COVID-19. These data include records of whether patients received drug treatments for their COVID-19, either as part of clinical trials or outside of them. “We didn’t really find that those treatments were helping, and some appeared to be associated with harm,” says Warner, pointing in particular to hydroxychloroquine as a treatment whose potential benefits did not pan out.

In a preprint paper posted Feb. 5, 2021, that has not yet been peer reviewed, Warner and his colleagues presented further data from CCC19 showing that in a group of blood cancer patients hospitalized with COVID-19, 30-day mortality was lower in those who received convalescent plasma than in those who did not receive the treatment. However, data from randomized clinical trials specifically in cancer patients is not yet available.

Against this backdrop, some researchers have initiated randomized clinical trials to test COVID-19 treatments in people with cancer. Investigators at the Ohio State University Comprehensive Cancer Center (OSUCCC) in Columbus, for instance, are studying whether Imbruvica (ibrutinib)—approved to treat various cancers including mantle cell lymphoma and chronic lymphocytic leukemia—can improve outcomes for hospitalized COVID-19 patients who have been diagnosed with cancer. Trial investigators hope to enroll 72 people with a variety of cancer types.

Researchers hope Imbruvica will be able to calm harmful inflammatory responses activated in people with COVID-19. The clinical trial at OSUCCC will determine whether cancer patients with severe COVID-19 who receive Imbruvica are less likely to die or experience respiratory failure than those on standard care.

Investigators at City of Hope National Medical Center in Duarte, California, meanwhile, are studying the effects of leflunomide, used to treat rheumatoid arthritis, in patients with severe COVID-19 who have been treated for cancer within the past two years. Based on preliminary data from a small study in China, investigators hypothesize that leflunomide may reduce inflammation and viral load in infected patients with cancer.

“Remdesivir doesn’t have a mortality benefit,” says lead investigator Sanjeet Dadwal, an oncologist at City of Hope who focuses on treating cancer patients with infections. In October 2020, remdesivir—now branded as Veklury—became the first drug to be approved for treatment of COVID-19 by the Food and Drug Administration (FDA), on the basis of research in the general population indicating it reduced time to recovery from COVID-19 in hospitalized patients. Since remdesivir shortens hospital stays but does not necessarily save lives, Dadwal says, there is still a need to test other drugs that might be more effective. Dadwal and his colleagues hope to enroll between 38 and 48 patients in their study of leflunomide. Investigators will track whether patients who are randomly assigned to receive leflunomide plus standard care have a lower mortality rate than those who receive the placebo plus standard care in a 28-day period after treatment begins.

Another ongoing trial, at Roswell Park Comprehensive Cancer Center in Buffalo, New York, is examining whether a combination of the drugs rintatolimod and interferon alfa-2b can improve outcomes for people with mild-to-moderate COVID-19 who have been treated for cancer within the past six months. The researchers hope these drugs will work together to activate patients’ immune systems and limit viral replication.

Mirroring the situation with COVID-19 treatment trials in the general population, trials of COVID-19 treatments for cancer patients don’t always pan out. In September 2020, the Leukemia & Lymphoma Society (LLS) announced the launch of its Beat COVID trial for hospitalized COVID-19 patients who had various blood cancers. Through this trial, 30 patients were set to receive standard care plus Calquence (acalabrutinib)—which is approved by the FDA to treat forms of leukemia and lymphoma—in hopes that it could also mitigate the risks of COVID-19. Another 30 patients were slated to receive only standard care for their COVID-19.

In November 2020, however, studies of Calquence as a COVID-19 treatment for the general population showed​ disappointing results. The drug did not reduce death rates or rates of respiratory failure in people with hospitalized with COVID-19. Given these poor results in a broader population, the LLS never began enrollment for Beat COVID.

Studying COVID-19 treatments in patients with cancer remains important, researchers say, particularly in vulnerable patients such as those with blood cancer. “Blood cancer patients often have low blood counts that make them ineligible for many of the clinical trials that are done in patients with COVID,” says John Byrd, an oncologist who focuses on blood cancers at OSUCCC and was involved in the Beat COVID trial. “When you don’t include a patient population in a trial, you can’t assume that that intervention is safe or beneficial” for the people excluded, Byrd says.​

Marcus A. Banks is a health journalist in New York City.