Safety and Immunogenicity of the BNT162b2 mRNA Covid-19 Vaccine in Patients after Allogeneic HCT or CD19-based CAR-T therapy

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INFECTIOUS DISEASE

Medical writer: Coco Chong | Last updated: 20 July 2021 | In: COVID-19, Infectious Disease, Vaccines

Article Keywords

haematopoietic cell transplantation, Pfizer, immune response, CAR-T, COVID-19, BioNTech, BNT162b2, SARS-CoV-2, COVID-19 vaccination

In this single centre prospective cohort study, the efficacy and toxicity of BNT162b2 vaccine were evaluated in patients who underwent haematopoietic cell transplantation (HCT) and chimeric antigen receptor T-cell (CAR-T) therapy.¹

A total of 79 eligible patients who received HCT (n = 65) and CAR-T therapy (n = 14) were enrolled and evaluated for immunologic recovery on CD19+, CD4+, and CD8+ cell blood levels. Vaccination was suggested based on the European Society for Blood and Marrow Transplantation recommendations. All patients were vaccinated with the BNT162b2 Coronavirus Disease 2019 (COVID-19) vaccine, which yielded 94.6% efficacy in a phase 3 study.²

The median age of patients was 65 years, and the median time from infusion of cells to vaccination were 32 months versus (vs) 9 months in the allogeneic HCT group vs CAR-T therapy group, respectively. In the HCT group, 62% of patients had active chronic graft vs host disease, and 58% were receiving immune suppressive therapy with mostly calcineurin inhibitors. Complete B-cell aplasia was observed in 11% of the overall patients. The overall antibody responses were 86% in HCT patients and 79% in CAR-T patients, which has proven to be efficacious among immunocompromised patients.

Serology testing found that 82% of patients in HCT group developed immunogenicity. However, the humoral response rate was only 36% in the CAR-T group. Adverse events that were grade 3 or higher occurred in 4.6% and 7% in the two groups, respectively. Although the adverse events resolved quickly in most cases, one secondary graft rejection occurred and was being investigated.

A multivariate analysis showed that factors associated with a positive humoral response included increased amount of time from the infusion of cells (p=0.032), female sex (p=0.028), and a higher number of CD19-positive cells (p=0.047). Higher numbers of CD19-positive cells and CD4 cells were predictive of positive ELISpot cellular response (p=0.49 and p=0.041).

The BNT162b2 mRNA COVID-19 vaccine showed promising immunogenicity in patients after allogeneic HCT or CAR-T therapy, but humoral response in CAR-T patients with B cell aplasia was more encouraging in allogeneic HCT group compared to CAR-T therapy. Adverse events were mostly mild and transient, so the vaccine is safe to use in immunosuppressed patients, but a longer follow-up and close monitoring of patients are required to test the persistence of antibodies.

Reference

Ram R, et al. Abstract S285. Presented at EHA 2021.

Polack FP, et al. N Engl J Med. 2020; 383(27)2603–2615

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Disclaimer

This article is not medical advice. Patients should seek personal assessment by a licenced specialist. Physicians are recommended to read the full publication(s) as cited in the article before making medical decisions. This article does not supersede nor replace the published article(s).