Immune responses to SARS-CoV-2 in vaccinated patients receiving checkpoint blockade immunotherapy for cancer

A novel protocol for de-isolating moderately and severely immunocompromised COVID-19 patients

Immunocompromised coronavirus disease 2019 patients are at a higher risk of prolonged viral shedding than immunocompetent patients. However, as of August 2023, there is no clear international standard for de-isolating vulnerable patients. A comprehensive assessment is advisable based on various information, such as the increase in immune escape of specific mutant strains as well as the patient's innate immunity and vaccination status; therefore, consultation with an infectious disease specialist is recommended. The patient population defined as moderately or severely immunocompromised by the Centers for Disease Control and Prevention and the European Centre for Disease Prevention and Control is significantly broad. A boundary between the two remains to be delineated, and the existing protocols allow the release of patients based on their symptoms alone. This may lead to an unnecessary extension or premature termination of isolation. In this study, we searched for studies, particularly those that used real-world data, discussed the results with experts in our hospital, and proposed new isolation criteria based on both testing and clinical symptoms. We classified patients into three groups namely severely, moderately, and mildly immunocompromised, defined by their background and the administration of immunosuppressive drugs. A separate flowchart for ending isolation is indicated for each group. This standard may be a useful support material, especially for non-specialists. Nevertheless, our criteria must be revised and added continuously; accumulating real-world data to support revision of and addition to the list is becoming increasingly important.

Immunogenicity and Safety of Vaccines against Coronavirus Disease in Actively Treated Patients with Solid Tumors: A Prospective Cohort Study

PURPOSE

We aimed to assess the humoral response to and reactogenicity of coronavirus disease 2019 (COVID-19) vaccination according to the vaccine type and to analyze factors associated with immunogenicity in actively treated solid cancer patients (CPs).

MATERIALS AND METHODS

Prospective cohorts of CPs, undergoing anticancer treatment, and healthcare workers (HCWs) were established. The participants had no history of previous COVID-19 and received either mRNA-based or adenovirus vector-based (AdV) vaccines as the primary series. Blood samples were collected before the first vaccination and after 2 weeks for each dose vaccination. Spike-specific binding antibodies (bAbs) in all participants and neutralizing antibodies (nAbs) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) wild-type, Delta, and Omicron variants in CPs were analyzed and presented as the geometric mean titer.

RESULTS

Age-matched 20 HCWs and 118 CPs were included in the analysis. The bAb seroconversion rate and antibody concentrations after the first vaccination were significantly lower in CPs than in HCWs. After the third vaccination, antibody levels in CPs with a primary series of AdV were comparable to those in HCWs, but nAb titers against the Omicron variant did not quantitatively increase in CPs with AdV vaccine as the primary series. The incidence and severity of adverse reactions post-vaccination were similar between CPs and HCWs.

CONCLUSION

CPs displayed delayed humoral immune response after SARS-CoV-2 vaccination. The booster dose elicited comparable bAb concentrations between CPs and HCWs, regardless of the primary vaccine type. Neutralization against the Omicron variant was not robustly elicited following the booster dose in some CPs, implying the need for additional interventions to protect them from COVID-19.

Safety of COVID-19 vaccines in subjects with solid tumor cancers receiving immune checkpoint inhibitors

The incidence of severe immune-related adverse events (irAEs) in cancer subjects receiving immune checkpoint inhibitors (ICIs) following COVID-19 vaccination and the relationship between the incidence of severe irAE and the interval between COVID-19 vaccination and ICI dose have not been established. We performed a retrospective study evaluating the incidence of irAEs in solid tumor subjects receiving ICI therapy who received any COVID-19 vaccinations since FDA authorization. irAEs were defined as severe with one or more grade 3 or above events (CTCAE v5.0), multiple organ involvement, or requiring hospitalization for management. Two hundred and eighty-four subjects who received COVID vaccinations from December 2020 and February 2022 were included in this analysis [median age at vaccination 67 years (IQR 59.0-75.0); 67.3% male]. Twenty-nine subjects (10.2%) developed severe irAEs, of which 12 subjects (41.4%) received ICI monotherapy, 10 subjects (34.5%) received combination ICI therapy with nivolumab and ipilimumab, and 7 subjects (24.1%) received ICI plus VEGFR-TKI therapy. Hospitalization occurred in 62% of subjects with severe irAEs, with a median duration of 3 days (IQR: 3.0-7.5 days). Immunosuppressive therapy was required in 79.3%, with a median duration of 103 days (IQR: 42.0-179.0). ICI therapy was discontinued in 51.7% of subjects with severe irAE; dosing was held or interrupted in 34.5%. Among severe irAEs, the median interval between vaccination and ICI treatment closest to the occurrence of severe irAE was 15.5 days (IQR: 10.0-23.0). In solid tumor cancer subjects receiving ICIs, COVID-19 vaccination is not associated with an increased incidence of severe irAEs compared to historical data and may be safely administered during ICI cancer therapy in subjects who lack contraindications.

Persistence of Immune Response Elicited by Three Doses of mRNA Vaccine against SARS-CoV-2 in a Cohort of Patients with Solid Tumors: A One-Year Follow-Up

The role and durability of the immunogenicity of the BNT162b2 mRNA vaccine against severe acute respiratory virus 2 (SARS-CoV-2), in cancer patients one year after receiving the third dose have to be elucidated. We have prospectively evaluated the long-term immunogenicity of the third dose of the SARS-CoV-2 BNT162b2 mRNA vaccine in 55 patients undergoing active treatment. Neutralizing antibody (NT Ab) titers against Omicron variants and total anti-trimeric S IgG levels were measured one year after the third dose. Heparinized whole-blood samples were used for the assessment of the SARS-CoV-2 interferon-γ release assay (IGRA). Thirty-seven patients (67.3%) showed positive total anti-trimeric S IgG one year after the third dose. Looking at the T-cell response against the spike protein, the frequency of responder patients did not decrease significantly between six and twelve months after the third dose. Finally, less than 20% of cancer patients showed an undetectable NT Ab titer against BA.1 and BA.5 variants of concern (VOCs). Underlying therapies seem to not affect the magnitude or frequency of the immune response. Our work underlines the persistence of humoral and cellular immune responses against BNT162b2 in a cohort of cancer patients one year after receiving the third dose, regardless of the type of underlying therapy.