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
n = 200
Papers screened using: Elasomeran Vaccination, Relevant Outcomes, Human Participants, Study Design, Sample Size, Full-Text Availability, Biological Outcomes Focus
n = 200
Papers screened out
n = 190
Papers included for extraction
n = 10

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 studies were available 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.

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 (RR 0.08 [0.07, 0.09], p<0.00001). Breakthrough infection rates were substantially lower with elasomeran (0.23%) compared to placebo (3.29%).

Among immunocompromised populations, seropositivity rates varied considerably by underlying condition. In lung cancer patients, 95.2% achieved seropositivity two weeks after vaccination (threshold 7.1 BAU/mL), with geometric mean titers of 655.45 BAU/mL (95% CI 593.5-723.8). In rheumatic disease patients, 82% achieved optimal humoral response (anti-RBD Ab >141 BAU/ml). Among IBD patients, mRNA-1273 recipients showed 100% seropositivity at 2 weeks with log10 antibody levels of 4.20.

Antibody Durability

Several studies tracked antibody persistence over time. In lung cancer patients, antibody levels were maintained at both two weeks and six months post-vaccination. However, in the broader cancer population, median titers declined significantly from 429 BAU/mL at 36 days to 139 BAU/mL at 3 months. Among initially seropositive patients, 10% converted to seronegative status by 3 months, including 5 with solid cancer and 19 with hematologic cancer. An additional 24% of patients with borderline levels at 36 days became seronegative by 3 months.

Response to Multiple Doses

In kidney transplant recipients, seroconversion increased progressively with additional doses. After two initial doses, 26% achieved seroconversion. A third dose improved seroconversion by an additional 31.2%, resulting in final rates of 71.7% for the heterologous scheme (2 CoronaVac + 2 BNT162b2) and 70.6% for the homologous scheme (3 BNT162b2). Similarly, in AML/MDS patients, seropositivity increased from 69.6% after one dose to 95.7% after two doses, with mean antibody titers rising dramatically from 315 to 3806.5.

Cellular Immune Response

Limited data on cellular immunity were available. Among cancer patients receiving mRNA vaccination, 46% of solid cancer patients and 45% of hematologic cancer patients exhibited positive T-cell responses. Of those with positive responses, 76% of solid cancer patients and 81% of hematologic cancer patients mounted both CD4+ and CD8+ T-cell responses, while 23% and 18% respectively elicited only CD8+ responses. Notably, 76% of seronegative patients did not elicit a T-cell response. The cancer meta-analysis reported an overall cellular response rate of 61% (95% CI 44-76%), with 59% in hematologic malignancies and 68% in solid malignancies.

Clinical Protection Outcomes

Breakthrough infection data were limited. Among lung cancer patients, only 0.5% (10 patients) contracted SARS-CoV-2 within a median of 19 days (IQR 5-76) after full vaccination. In kidney transplant recipients, 10 patients experienced breakthrough infections during a 5-month follow-up, with no deaths reported.

Factors Modifying Immune Response

Cancer Treatment and Immunosuppression

Specific cancer treatments substantially impacted humoral response. In multiple myeloma patients, those receiving proteasome inhibitors had median antibody titers of 156 U/ml, while those on anti-CD38 monoclonal antibodies had median titers of 265 U/ml, both lower than other treatment groups. Conversely, patients receiving lenalidomide maintenance had median titers of 1681.2 U/ml, and those who had undergone autologous stem cell transplantation showed median titers of 1042 U/ml.

Disease status at vaccination significantly influenced immune response, with patients in complete remission achieving markedly higher antibody titers than those with progressive disease.

Disease-Specific Response Patterns

Among hematologic malignancies, specific diagnoses showed markedly different seropositive rates. Only 11% of mantle cell lymphoma patients achieved seropositivity, while 55% of CLL/SLL patients and 62% of follicular lymphoma patients became seropositive.

Vaccine-Specific Differences

In rheumatic disease patients, those receiving mRNA vaccines showed 85% optimal humoral response versus only 69% with viral vector vaccines.

Safety and Tolerability

Safety data were limited across studies. In AML/MDS patients, mild injection site pain, fatigue, headache, and arm swelling were the most common adverse events. Two AML patients experienced disease relapse post-vaccination, though no direct link to vaccination was established.