Impaired immunogenicity of the Pfizer/BioNtech (BNT162b2) COVID-19 vaccine in patients treated for solid tumours

August 2021 Pharma News Tobias Rawson

Editor’s pick of Sylvie Rottey, MD, PhD, medical oncologist, UZ Gent

To date, there is still limited evidence on the efficacy and tolerability of the BNT162b2 (Pfizer/BioNtech) COVID-19 vaccine in patients in the active phase of treatment for solid tumours. In this light, a BNT162b2 vaccine monitoring observatory (VMO) was set up in Nice, France. Results of the first 122 assessable patients report a decreased immunogenicity with lower median anti-S antibody levels in solid tumour patients as compared to healthy volunteers.

Cancer patients in the active phase of treatment are a population at risk of coronavirus disease-19 (COVID-19) with poor prognosis. Although a majority of cancer patients express their will to be vaccinated, no data were available in terms of vaccine efficacy and tolerability, because these patients were excluded from initial registrational trials. Therefore, a BNT162b2 (Pfizer/BioNtech) vaccine monitoring observatory (VMO) was set up for vaccinated patients under active treatment in the Department of Oncology of the Saint-Jean Polyclinic (Nice, France). Apart from cancer patients, a control group of healthy volunteers, i.e. without known ongoing cancer, was formed and vaccinated during the same period. Serological testing of immunogenicity was conducted in these patients at week 0 during the first vaccination, during the booster (at week 3-4) and 3-4 weeks after the booster (i.e. week 6-8). Anti-SARS-CoV-2 assays were used to detect antibody binding to SARS-CoV-2 spike (S) protein receptor-binding domains. A serum result of ≥ 0.8 UI/ml was considered to be positive. Reported now, are the first 122 assessable patients with solid tumours vaccinated between January and March of 2021.  The median age of the 122 patients was 69.5 years (range: 44-90 years), with 64 men (52.5%) and 58 women (47.5%).

Significantly lower antibody levels compared to the control group

Among the 122 assessable patients, 105 (86.0%) were treated with chemotherapy, with or without targeted therapy. At the first serological analysis at weeks 3-4, the seroconversion of cancer patients was less than the healthy control group. During this period, 47.5% (95%CI: 38.4-56.8) of cancer patients had an anti-S seroconversion while, during the same time period, the control group experienced a 100% seroconversion (95%CI: 75.3-100.0). At the second assessment post-booster (weeks 6-8), the seroconversion rate of cancer patients improved to 95.2% (95%CI: 83.8-99.4), which was more comparable to the control groups seroconversion of 100% again at this second data point (95%CI: 85.7-99.4). Less patients receiving chemotherapy experienced anti-S seroconversion at weeks 3-4 after the first dose compared to patients who were not receiving chemotherapy, or patients receiving targeted therapy alone (42.9% vs. 76.5%, P= 0.016).

Overall, median anti-S antibody levels were significantly lower than the levels observed in the control group at weeks 3-4 (0.52 UI/ml vs. 21.6 UI/ml, P< 0.001). Post-booster evaluation followed a similar trend, with cancer patients achieving a median anti-S antibody level of 245.2 UI/ml, compared to a median of 2,517 UI/ml in healthy individuals (P< 0.001). After the booster dose, the median anti-S antibody levels increased significantly for both patients and healthy volunteers (p< 0.001). Encouragingly, no adverse events were reported in either cohorts.


There is an impaired immunogenicity of the BNT162b2 anti-SARS-CoV-2 vaccine in patients treated for solid tumours. Evident from serological testing, these patients took longer to develop an immune response, which was weaker overall, compared to a healthy control cohort. These findings have direct applicability to clinical practice, and these patients should continue to adhere to strict social distancing measures for at least 6-8 weeks after the first dose of the vaccine. It is also unknown how long protection lasts in these patients, and how well they are protected against rising COVID-19 variants.


Palich R, Veyri M, Marot S, et al. Impaired immunogenicity of BNT162b2 anti-SARS-CoV-2 vaccine in patients treated for solid tumours. Annals of Oncol. 2021;325(17):1784-1786.