Vaccine Immune Recovery After Leukemia

Study Overview
=================
Brief Summary
-----------------
This observational study aims to assess recovery of the immune system and immunity to vaccine-preventable diseases in children and adolescents who recently completed treatment for acute lymphoblastic leukemia (ALL). Several children's hospitals in the United States are participating in the study, which will enroll approximately 75 pediatric participants. The study is intended to determine the rate of infection after leukemia treatment and to inform future studies and recommendations about whether children and adolescents who have leukemia should receive additional vaccine doses or boosters after treatment.

Official Title
-----------------
A Prospective Cohort Study to Define Infectious Burden, the Seroprevalence of Vaccine Preventable Pathogens and Immune Recovery in the First Year Following Completion of Therapy in Patients With Acute Lymphoblastic Leukemia (ALL)

Conditions
-----------------
Acute Lymphoblastic Leukemia, Pediatric

Intervention / Treatment
-----------------
* Other: Observational only


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Children, adolescents, and young adults diagnosed with B or T ALL at age 12 months or older Completed ALL chemotherapy within the past three months or will complete ALL chemotherapy in the upcoming three months Three years of age or older at time of enrollment Exclusion Criteria: Diagnosis of infant ALL Evidence of disease relapse History of primary immunodeficiency (except related to Down Syndrome) History of a stem cell transplant or cellular immunotherapy History of prior malignancy or condition requiring chemotherapy other than for current ALL diagnosis

Ages Eligible for Study
-----------------
Minimum Age: 3 Years
Maximum Age: 31 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Children, adolescents, and young adults who recently completed ALL treatment<br>This cohort of participants who recently completed leukemia therapy will be assessed for infection incidence during the year following treatment and give blood samples to be measured for antibodies to vaccine-preventable diseases. A small subset will also have their blood samples tested for B and T cell recovery. | Other: Observational only<br>* Blood samples will be tested to measure antibodies to vaccine-preventable diseases and immune recovery<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incident infection rate in a cohort of subjects in the first year following completion of acute lymphoblastic leukemia therapy | Infections will include both clinical and/or microbiologically confirmed infections. All unique infections for a given subject will be captured and included in the final infection rate per person time estimate. Infections will also be reported in subsets of infections such as microbiologically confirmed or clinically defined infections. The total number of unique infections identified within the first year after completing chemotherapy will be reported as a rate per 1000 follow-up days. This rate will be reported for the entire cohort, by study site, and by demographics. This outcome will also be reported within subsets of infection type reported as a rate per 1000 follow-up days for the entire cohort, by study site and by specific demographic variables. All infection rates will be reported as a post estimate with 95 percent confidence intervals. Patients will be censored at time of lost to follow-up or death. | 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of patients with seroprevalence of measles antibodies at each study timepoint | The seroprevalence proportions for measles antibodies will be determined for the entire cohort and by demographics at each study follow-up time point (3, 6, and 12 months). Additionally, seroprevalence at each time point will be described for participants who had and had not completed their primary vaccine series before starting chemotherapy. | 1 year | 
| Proportion of patients with seroprevalence of varicella antibodies at each study timepoint | The seroprevalence proportions for varicella antibodies will be determined for the entire cohort and by demographics at each study follow-up time point (3, 6, and 12 months). Additionally, seroprevalence at each time point will be described for participants who had and had not completed their primary vaccine series before starting chemotherapy. | 1 year | 
| Proportion of patients with seroprevalence of pneumococcus antibodies at each study timepoint | The seroprevalence proportions for pneumococcal antibodies (23 serotypes) will be determined for the entire cohort and by demographics at each study follow-up time point (3, 6, and 12 months). Additionally, seroprevalence at each time point will be described for participants who had and had not completed their primary vaccine series before starting chemotherapy. | 1 year | 
| B lymphocyte recovery in a subset of patients | B lymphocyte subsets will be measured for a subset of the 75 enrolled subjects. These measurements will be reported for each subject at approximately 3, 6, and 12 months. The trajectory of these measurements will be displayed graphically across the three timepoints of interest to assess relative recovery of lymphocyte quantities after completion of ALL chemotherapy. | 1 year | 
| T lymphocyte recovery in a subset of patients | T lymphocyte subsets will be measured for a subset of the 75 enrolled subjects. These measurements will be reported for each subject at approximately 3, 6, and 12 months. The trajectory of these measurements will be displayed graphically across the three timepoints of interest to assess relative recovery of lymphocyte quantities after completion of ALL chemotherapy. | 1 year | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
acute lymphoblastic leukemia, chemotherapy, antineoplastic agents, varicella vaccine, chickenpox vaccine, pneumococcal vaccines, measles vaccine