Israeli data support short-term safety of BNT162b2 mRNA COVID-19 vaccine in ICI-treated cancer patients

Data from two centres in Israel support short-term safety of the BNT162b2 mRNA coronavirus disease 2019 (COVID-19) vaccine in cancer patients treated with immune checkpoint inhibitors (ICIs), including those with previous immune-related side effects from ICIs.

The study included 134 ICI-treated cancer patients (ICIs alone, n=116; ICIs plus chemotherapy, n=18) who received two doses of the BNT162b2 mRNA COVID-19 vaccine at the Oncology Division of the Tel Aviv Sourasky Medical Center (TLVMC) and the Oncology Unit of the Bnei-Zion Medical Center between 11 January and 25 February 2021. Side effects were monitored at 17–21 days after the first vaccine dose and at a median of 19 days after the second vaccine dose using detailed telephone questionnaires. Vaccine-related side effects in ICI-treated cancer patients were compared with those in age- and sex-matched healthy controls. [Lancet Oncol 2021;doi:10.1016/S1470-2045(21)00155-8]

Results showed a similar profile of vaccine-related side effects between ICI-treated cancer patients and healthy controls, apart from muscle pain, which was significantly more common in the cancer patients (p=0.024). “However, no immune-related myositis was diagnosed after vaccination in either cancer patients or controls,” the investigators reported.

Among ICI-treated cancer patients, the most common side effects after the first vaccine dose were local, with 21 percent of patients reporting pain at the injection site. The most common systemic side effects after the first vaccine dose were fatigue (4 percent), headache (2 percent), muscle pain (2 percent), and chills (1 percent).

Similar to previous reports, local and systemic side effects were more common after the second vaccine dose among the ICI-treated cancer patients. The most common local side effects were pain at the injection site (63 percent), local swelling (9 percent), and local rash (2 percent), while the most common systemic side effects were muscle pain (34 percent), fatigue (34 percent), headache (16 percent), fever (10 percent), chills (10 percent), gastrointestinal complications (10 percent), and flu-like symptoms (2 percent). None of the reported side effects required hospital admission or special intervention.

“Most importantly, no new immune-related side effects or exacerbation of existing immune-related side effects were observed,” the investigators pointed out.

No significant difference in rates of systemic side effects after the second vaccine dose was found between patients with previous immune-related side effects and those without (33 percent vs 34 percent; p=0.94).

“Importantly, even in patients with previous immune-related side effects, the vaccine-related side effects were mild and did not lead to admission to hospital or cessation of cancer treatment,” the investigators noted.

“Our data support the short-term safety of the BNT162b2 mRNA COVID-19 vaccine in cancer patients treated with ICIs,” they continued. “Considering the high mortality of cancer patients who contract COVID-19, which can be up to 40 percent in some populations, the benefits of vaccination seem to outweigh the potential harms.”

Although further studies are needed, the investigators said their findings might provide reassurance for the use of other COVID-19 vaccines in ICI-treated cancer patients.

“The decision to vaccinate patients in regions severely affected by the pandemic cannot wait for accumulating data from well designed, prospective clinical trials. Thus, despite the absence of evidence, the 5 March 2021 update of the American Society of Clinical Oncology guidelines state that ‘at this time, patients undergoing treatment may be offered vaccination against COVID-19 as long as any components of the vaccine are not contraindicated’,” they pointed out.