Cancer Drug Timing Could Render COVID-19 Vaccines Ineffective

Researchers at Stanford Medicine recently published a study that found certain cancer patients who have been treated with rituximab or similar drugs respond poorly or not at all to subsequent COVID-19 mRNA vaccines.

In contrast, mRNA vaccination immediately before such cancer treatment generates durable antibody responses, reported the study published by the peer-review journal Blood Cancer Discovery on March 4, 2022.

Rituximab, marketed under the brand name Rituxan, targets a molecule called CD-20 found on the surface of immune cells called B cells.

The drug is often used in people with lymphomas, a type of blood cancer. In 2021, around 90,000 people were diagnosed with the disease in the U.S.

The U.S. FDA initially approved Rituxan in 1997.

“This finding is likely to be practice-changing,” commented Ronald Levy, MD, professor of oncology, Stanford Medicine, in an article issued on February 2, 2022.

“We found that antibody responses to the COVID-19 vaccine were blunted in people who received rituximab up to a year before vaccination. But if they were vaccinated prior to treatment, most responded and were able to hold on to that response during their rituximab treatment.”

The researchers did not directly assess whether patients treated with rituximab or other drugs targeting CD-20 before being vaccinated subsequently had higher infection rates with the virus that causes COVID-19.

But the findings strongly suggest that people who are newly diagnosed with lymphoma should be offered the vaccine before beginning rituximab or similar drugs.

Financial support came from the NIH, Leukemia & Lymphoma Society, Fast Grants, and the Stanford ChEM-H Innovative Medicines Accelerator program. In addition, the researchers disclosed various industry relationships.

Note: This news article aggregated and edited for clarity several content sources, and curated it for mobile readers.