Growing evidence suggests that patients with cancer have better responses to the Moderna COVID-19 vaccine than to the Pfizer-BioNTech vaccine.1-6

Studies designed to monitor the level of immune response after vaccination have revealed a difference in protective antibodies between patients who received the Pfizer-BioNTech and Moderna vaccines, raising questions as to whether patients with cancer should preferentially be given the latter.

One of these studies was recently presented at the NCCN Annual Meeting.1,2 The study involved 240 patients with chronic lymphocytic leukemia (CLL) and other non-Hodgkin lymphomas (NHLs) who were tested for post-vaccination antibodies. The cohort included patients who were and were not receiving active treatment. 

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The results showed that patients with CLL had better antibody responses after completing a vaccination series with the Moderna vaccine than with the Pfizer-BioNTech vaccine. The rate of antibody response was 61% with Moderna and 44% with Pfizer-BioNTech (P =.028).

For patients with other NHLs, the largest share of whom had Waldenstrom macroglobulinemia (WM), a difference in response was noted but did not quite reach statistical significance. In the WM group, the antibody response rate was 88% with the Moderna vaccine and 54% with the Pfizer-BioNTech vaccine (P =.11). For the remaining NHL patients, the antibody response rate was 80% and 70%, respectively (P =.56).

“When we started this study, we were not really thinking that different vaccines may give different responses,” said Shuo Ma, MD, PhD, senior author of the work and an oncologist and associate professor of medicine at the Feinberg School of Medicine at Northwestern University in Chicago.

“We wanted to look at our patient population in general to assess response to the vaccines. Finding a higher response with the Moderna vaccine compared to Pfizer in certain patient populations was a surprise to us.” 

Types of Response

In their study, Dr Ma and colleagues assessed antibody titers using the Access SARS-COV-2 assay. An antibody response was defined as a positive total antibody or spike protein antibody result.

“Looking at spike protein antibodies as a measure of response is a very convenient way for us to look at the vaccine response in clinical practice, but there are several caveats,” Dr Ma explained. “We are not using a neutralizing antibody assay, and other cellular responses can occur.” 

Dr Ma added that she is currently conducting research looking at T-cell responses in patients with CLL and other NHLs. 

A study in which researchers did look at neutralizing antibodies, among 238 patients with multiple myeloma, showed that 54% of vaccinated patients overall had detectable levels of neutralizing antibodies.3,4 

The prevalence of neutralizing antibodies was 67% among patients who received the Moderna vaccine and 48% among patients who received the Pfizer-BioNTech vaccine (P =.006). 

Another study included 500 patients with a variety of solid and hematologic cancers, as well as 137 other immunocompromised patients and 204 healthy control individuals.5,6 

In this study, the duration of neutralizing antibody response in patients with solid cancers was significantly longer after the Moderna vaccine (range, 221-226 days, depending on the SARS-CoV-2 variant) than after the Pfizer-BioNTech vaccine (range, 146-161 days).