Protecting Patients With Blood Cancers From COVID-19

Blood cancer patients are highly vulnerable to COVID-19 infection. Now mounting evidence suggests they may be also among the least protected by vaccines.  

Blood Cancer Discovery, a journal of the American Association for Cancer Research (AACR), has recently published studies investigating the efficacy of the mRNA COVID-19 vaccines in patients with hematologic malignancies. 

In a study titled “Disease and therapy-specific impact on humoral immune responses to COVID-19 vaccination in hematologic malignancies,” researchers reported that patients with leukemia, lymphoma, and multiple myeloma all had fewer antibodies at one and three months post-vaccination than people without cancer. Peak antibody response was stronger in females than males, and the Moderna vaccine elicited a stronger response than the Pfizer/BioNTech vaccine. 

Lead author David J. Chung, MD, PhD, of Memorial Sloan Kettering Cancer Center (MSK) and colleagues also found that many patients had insufficient neutralizing capacity following vaccination despite positive antibody titers. This study represents the largest dataset of vaccine responses among patients with hematologic malignancies that includes both binding and neutralizing antibody data. The sample size was large enough to determine that therapies including venetoclax, kinase inhibitors, and B-cell antigen-targeting drugs hindered patients’ immune response to the vaccine, while single-agent immunomodulatory agents such as lenalidomide or pomalidomide for multiple myeloma did not.  

A companion study, titled “Predictors of Humoral Response to SARS-CoV-2 Vaccination after Hematopoietic Cell Transplantation and CAR T Cell Therapy,” investigated patients’ response to vaccination against COVID-19 following treatment with cellular therapies such as allogeneic and autologous hematopoietic cell transplant and CAR T-cell therapy.  

Lead author Roni Tamari, MD, also of MSK, and colleagues found overall high response rates among recipients of cellular therapies, though the type of therapy and time since treatment impacted patients’ antibody levels and neutralizing capacity. Response to vaccination correlated with degree of immune recovery after transplantation, which can be tracked by simple blood tests, thus offering a cue to when these patients may regain the ability to respond to mRNA COVID-19 vaccines.  

These papers add to the growing body of research regarding the efficacy of COVID-19 vaccines in different groups, and can help inform optimal vaccination approaches, including booster vaccination strategies, for patients with a history of or in active treatment for hematologic malignancies.  

This week, Blood Cancer Discovery’s “Science in Society” section featured an article titled “How to provide the needed protection from COVID-19 to patients with hematologic malignancies.” In this article, a diverse group of cancer immunology and hematology-oncology experts from the University of California Los Angeles, Emory University, New York University, Stanford University, the National Cancer Institute, and the Leukemia & Lymphoma Society analyzed responses to COVID-19 vaccines among blood cancer patients reported in 18 clinical papers. This largest-to-date analysis encompasses thousands of patients from many countries and across cancer and therapy types. It demonstrates that hematologic cancer patients have impaired antibody response to vaccination, highlighting the urgent need to provide additional protection against COVID-19 to this vulnerable population.  

“Patients with certain hematologic malignancies are particularly vulnerable during the COVID-19 pandemic, and require additional measures to protect them from this and other viral infections and to allow them to proceed with the treatment of their malignancies,” the authors wrote.

The authors, including AACR Past President Antoni Ribas, MD, PhD, FAACR, have developed evidence-based guidance on such protection for patients and their caregivers. The recommendations include additional vaccine doses, continued adherence to wearing masks and social distancing, frequent COVID testing even among vaccinated people; 100 percent vaccination of their caregivers and adult family members; and prioritizing vaccine availability to these groups.  

The authors also call on policymakers to provide resources for clinicians and researchers to find out how immune protection in these patients can be improved by additional vaccine doses, optimizing vaccination relative to cancer treatment timing, and passive immunity prophylaxis, through the administration of monoclonal antibodies and convalescent plasma, among others.  

In patients with weakened immunity, prolonged COVID-19 infection creates opportunities for the evolution of viral variants of concern to the general population. Thus, protecting blood cancer patients from COVID infection is also a matter of global public health. 

All AACR journal content related to COVID-19 is freely available in the COVID-19 & Cancer Resource Center.