Antibodies Go Missing After COVID-19 Vaccination in Some Blood Cancer Patients

About 1 in 4 blood cancer patients fail to produce detectable antibodies after COVID-19 vaccination, but results vary substantially by type of blood cancer, according to a new study.

The study is the largest of blood cancer patients and COVID-19 vaccination to date, encompassing over 1,400 patients, the Leukemia & Lymphoma Society (LLS) said in a press release. LLS conducted the study, which was published in Cancer Cell.

LLS estimates that nearly 250,000 blood cancer patients in the U.S. will not have detectable antibodies following COVID-19 vaccination.

While some patients with hematologic malignancies will not mount a full antibody response compared to healthy individuals, vaccines are safe and offer protection to the majority of blood cancer patients, said Gwen Nichols, M.D., chief medical officer at LLS.

“But not everyone will be protected, and blood cancer patients are at increased risk of serious illness and death from COVID-19. We encourage blood cancer patients to take every measure to protect themselves from COVID-19 by getting vaccinated and continuing to take preventative precautions. This includes wearing a mask, social distancing and avoiding crowds and poorly ventilated indoor spaces,” Nichols said.

Lee Greenberger, Ph.D.

The LLS also supports the recent FDA decision to allow the use of a third dose of the Moderna and Pfizer/ BioNTech vaccines in certain immunocompromised individuals, Lee Greenberger, Ph.D., chief scientific officer at LLS, told Managed Healthcare Executive®. “This is a critical step in ensuring that those most vulnerable to COVID-19 — including patients with blood cancers —get as much protection as possible from COVID-19 vaccination,” he said.

Even after receiving a third dose of the COVID-19 vaccine, blood cancer patients should continue taking preventive precautions such as wearing a mask and social distancing, Greenberger advised. “Antibodies are just one piece of the puzzle. There are other ways our immune systems respond to vaccination that may provide protection.” The immune system’s T cells also fight off infection.

The blood cancer pateint population that fails to make antibodies is restricted to those with B cell malignancies, Greenberger explained. “B cells make antibodies. Therefore, those diseases that impair normal B cell function, or those patients taking therapies to impair the B cell derived tumors (which very often wipe out normal B-cells), have impaired antibody response to vaccination.” The B cell malignancies include most cases of non-Hodgkin lymphoma, chronic lymphocytic leukemia and mantle cell lymphoma.

LLS’s National Patient Registry has been tracking antibody responses of more than 40 patients who have already received a third dose of the COVID-19 vaccine and expects to share results soon.

The study found that seronegative (a negative result in a blood test) rates vary by blood cancer type and treatment. For example, non-Hodgkin lymphoma patients are less likely to have detectable antibodies, with seronegative rates after vaccination ranging from 21% to 56%. Many of these patients were treated with anti-CD20 antibodies such as rituximab (sold under the brand name Rituxan) which eliminates B cells that make antibodies, LLS said.

Among leukemia patients, those with chronic lymphocytic leukemia (CLL) are most likely to be seronegative. Thirty-six percent of patients with CLL, the most common leukemia in U.S. adults, were seronegative after vaccination. Nearly three in 10 of them had no cancer therapy in the past two years, showing that the disease itself may impair the B cell function needed to make antibodies to vaccines.

However, the seronegative rates were even higher in CLL patients who were treated within the last two years with drugs that impair B-cells, including BTK inhibitors such as Imbruvica (ibrutinib), anti-CD20 antibodies, or combinations of these therapies or their use with venetoclax, a BCL2 inhibitor.

Multiple myeloma patients had higher rates of detectable antibodies compared to other blood cancers. Only 5% of patient with multiple myeloma were seronegative. Other studies, though, have reported higher seronegative rates (up to 15%) in multiple myeloma patients, LLS said.

The blood cancer pateint population that fails to make antibodies is restricted to those with B cell malignancies, Greenberger explained. “B-cells make antibodies. Therefore, those diseases that impair normal B-cell function, or those patients taking therapies to impair the B-cell derived tumors (which very often wipe out normal B-cells), have impaired antibody response to vaccination.”