Immune Response to Third Dose of SARS-CoV-2 Vaccine in a Cohort of Cancer Patients on Active Treatment

Study Overview
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Brief Summary
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The Coronavirus Disease 2019 (COVID-19) pandemic has claimed over 5 million lives globally. Fortunately, a substantial and growing number of SARS-CoV-2 vaccines with very high efficacy have been developed, manufactured, and rapidly approved. Novel mRNA vaccines such as the BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna) have reported a stunning >94% efficacy against COVID-19. However, global access has not been equitable, with many low- and middle-income countries having no vaccine access or access under emergency use mainly to traditional inactivated SARS-CoV2-2 vaccines such as BBIBP-CorV (Sinopharm Beijing), CoronaVac (Sinovac) and BBV152 (Bharat Biotech). Emerging studies have shown that lower concentrations of neutralizing antibodies (Nab) are attained after CoronaVac than after a mRNA-based vaccine in healthy individuals. This difference seems to be more pronounced in immunocompromised patients who are at higher risk of severe COVID-19 and death from COVID-19. As such several countries including United States, Israel and Chile have recommended a third vaccine dose for this vulnerable population. In this observational study we will explore the humoral response to the BNT162b2 vaccine in patients who received two previous doses of the inactivated vaccine Coronavac or two doses of BNT162b2.

Official Title
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Immune Response to Third Dose of SARS-CoV-2 Vaccine in a Cohort of Cancer Patients on Active Treatment

Conditions
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Sars-CoV-2 Infection

Intervention / Treatment
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* Biological: Three doses of BNT162b2 (observational)
* Biological: Two doses of Coronavac and one dose BNT162b2 (observational)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Vaccination with two doses of Coronavac vaccine or BNT162b2 vaccine Eastern Cooperative Oncology group performance status < 3 Exclusion Criteria: Previous SARS-CoV-2 infection Vaccination with booster vaccine more than 12 weeks before informed consent Intravenous inmunoglobulin therapy 60 days before informed consent Any condition that could interfere with the paticipant´s participation during the study in the opinion of the treating investigator.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Three doses of BNT162b2.<br>Cancer patients on active cytotoxic treatment who received three doses of BNT162b2. | Biological: Three doses of BNT162b2 (observational)<br>* BNT162b2 (COVID 19 mRNA vaccine)<br>|
| Two doses of Coronavac and one of BNT162b2.<br>Cancer patients on active cytotoxic treatment who received two doses of Coronavac and one dose of BNT162b2. | Biological: Two doses of Coronavac and one dose BNT162b2 (observational)<br>* BNT162b2 (COVID 19 mRNA vaccine) Coronavac (COVID 19 inactive vaccine)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of positive neutralizing antibodies 8 to 12 weeks after third dose BNT162b2 (booster vaccine). |  | 8 to12 weeks after third dose BNT162b2. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Neutralizing geometric mean titers 8 to 12 weeks after third dose BNT162b2 (booster vaccine) |  | 8 to12 weeks after third dose BNT162b2. |