Immune Response to Elasomeran Vaccination

What is the evidence for immune response and protection after Elasomeran vaccination?

Evidence demonstrates that elasomeran vaccination induces robust immune responses and clinical protection across most populations, though patients with hematologic malignancies and those on B-cell-depleting therapies show attenuated responses that improve with additional doses.

Abstract

Elasomeran vaccination demonstrates high efficacy in healthy populations, with risk ratios of 0.08 for preventing COVID-19 and breakthrough infection rates of 0.23%. In immunocompromised populations, humoral responses vary substantially by underlying condition: seropositivity rates reach 95.2% in lung cancer patients, 91.7% in multiple myeloma, and 82% in rheumatic disease patients, but only 60-66% in hematologic malignancies. Cellular immune responses occur in approximately 46% of cancer patients, with most mounting both CD4+ and CD8+ T-cell responses. Antibody titers decline substantially over time, decreasing from median 429 to 139 BAU/mL between 36 days and 3 months post-vaccination, with 10% of initially seropositive patients converting to seronegative status. Response heterogeneity is explained by specific mechanisms: B-cell-depleting therapies (anti-CD20, anti-CD38) profoundly suppress antibody production, disease remission predicts superior response (median titers 1242 vs 221.5 U/ml), and mRNA vaccines induce higher antibody levels than viral vector vaccines. Additional doses substantially improve seroconversion in immunocompromised patients, increasing rates from 26% after two doses to 71.7% after four doses in kidney transplant recipients and from 69.6% to 95.7% after a second dose in AML/MDS patients. Clinical protection remains robust in most immunocompromised populations, with breakthrough infection rates of only 0.5% in lung cancer patients. The evidence indicates that while elasomeran induces strong immune responses in most populations, patients with hematologic malignancies and those receiving B-cell-depleting therapies require additional doses and may need more frequent boosting to maintain protective immunity.

Methods

We analyzed 10 sources from an initial pool of 200, using 7 screening criteria. Each paper was reviewed for 8 key aspects that mattered most to the research question.

Records from Elicit search: 200 papers screened using: Elasomeran Vaccination, Relevant Outcomes, Human Participants, Study Design, Sample Size, Full-Text Availability, Biological Outcomes Focus.

Data extraction

Study Design:

• Extract study design characteristics relevant to evaluating elasomeran immune response and protection evidence, including study type, sample size for elasomeran recipients, control/comparison groups, follow-up duration, primary vs secondary analysis of elasomeran outcomes, risk of bias indicators.

Population Characteristics:

• Extract participant characteristics that may affect elasomeran immune response and protection, including age distribution, immunocompromising conditions, prior COVID-19 infection status, comorbidities affecting immune function, active cancer treatment status, performance status measures.

Vaccination Details:

• Extract elasomeran vaccination protocol and completion details, including dose administered, vaccination schedule, number of doses received by participants, completion rates for full vaccination series, time from last dose to outcome measurement, any booster doses included in analysis.

Humoral Immune Response:

• Extract antibody response measures including seropositivity rates, quantitative antibody titers, antibody types measured, assay methods and platforms, seroconversion rates from baseline, and antibody levels at different time points.

Cellular Immune Response:

• Extract T-cell and cellular immune response measures including CD4+ and CD8+ T-cell response rates, T-cell assay methods, cytokine production patterns, T-cell response persistence over time.

Clinical Protection Outcomes:

• Extract clinical protection effectiveness including breakthrough infection rates, severity of breakthrough infections, hospitalizations, deaths post-vaccination.

Response Modifying Factors:

• Extract factors that influenced immune response or protection after vaccination including specific treatments affecting response, disease status at vaccination, demographic factors, laboratory parameters correlating with response.

Safety and Tolerability:

• Extract safety profile of elasomeran vaccination in the study population including local/systemic reactions and serious adverse events potentially related to vaccination.

Results

Characteristics of Included Studies

Ten studies met the inclusion criteria, comprising two meta-analyses, one scoping review, and seven primary observational studies. Full text was available for six studies, while four only as abstracts.

The studies predominantly enrolled immunocompromised populations, including patients with hematologic malignancies, solid tumors, transplant recipients, and autoimmune diseases. Most patients in cancer studies were receiving active treatment at vaccination. The median age ranged from 51 years in IBD patients to 68 years in AML/MDS patients. One meta-analysis focused exclusively on healthy populations over 16 years.

Humoral Immune Response

Seropositivity Rates in Healthy vs Immunocompromised Populations

In the healthy population meta-analysis, both BNT162b2 and mRNA-1273 demonstrated high efficacy in preventing COVID-19 compared to placebo. Breakthrough infection rates were substantially lower with elasomeran (0.23% compared to placebo). Among immunocompromised populations, seropositivity rates varied considerably by underlying condition. In lung cancer patients, 95.2% achieved seropositivity two weeks after vaccination, with geometric mean titers of 655.45 BAU/mL.

Patients with hematologic malignancies consistently demonstrated lower seropositivity rates compared to those with solid tumors.

Antibody Durability

Multiple studies tracked antibody persistence over time. In lung cancer patients, the levels were maintained at both two weeks and six months post-vaccination. However, in the broader cancer population, median titers declined significantly.

Response to Multiple Doses

In kidney transplant recipients, seroconversion increased progressively with additional doses.

Cellular Immune Response

Limited data on cellular immunity were available. Among cancer patients receiving mRNA vaccination, 46% exhibited positive T-cell responses.

Clinical Protection Outcomes

Breakthrough infection data were limited. Among lung cancer patients, only 0.5% contracted SARS-CoV-2 after full vaccination.

Factors Modifying Immune Response

Cancer Treatment and Immunosuppression

Specific cancer treatments substantially impacted humoral response.

Disease-Specific Response Patterns

Among hematologic malignancies, specific diagnoses showed markedly different seropositive rates. Higher rates were observed in certain patient groups compared to others.

Vaccine-Specific Differences

In rheumatic disease patients, those receiving mRNA vaccines showed a significantly higher optimal humoral response.

Safety and Tolerability

Limited safety data. Mild adverse events were reported among patients, but no direct links to vaccination were established. "Safe" observed immune responses were noted.

Synthesis

The evidence demonstrates substantial heterogeneity in immune responses to elasomeran vaccination, reflecting distinct immune capacity margins across different populations.