P-1507. Humoral responses to two versus one dose of pneumococcal conjugate vaccine 20 (PCV20) in lymphoma survivors at 3 months follow up

Abstract Background Vaccination against Streptococcus pneumoniae could benefit lymphoma survivors by preventing serious infections. However, B cell lymphoma survivors who were previously treated with anti-CD20 therapy may have suboptimal humoral responses to a single dose of pneumococcal vaccination. Our study aims to compare the humoral responses within 3 months from a single dose or two doses of PCV20 in B cell lymphoma survivors in remission and at least 1 year from the last dose of anti-CD20.Table 1:Baseline demographics and serologiesFigure 1:Comparison in humoral response in patients with 1 or 2 doses of PCV 20 at 1 month Methods We conducted an open-label randomized trial of PCV20 in B-cell lymphoma survivors who received prior anti-CD20 therapy but no cellular therapy at our center and were in complete remission for at least 1 year. We enrolled 30 patients who were randomized 1:1 to receive 1 or 2 doses of PCV20 (1 month apart). Pneumococcal serologies were measured at enrollment, 1 month and 3 months after the initial vaccination. We compared humoral responses at 1 month and 3 months from the first dose and only serotypes included in the PCV20 vaccination were included.Figure 2:Comparison in humoral response in patients with 1 or 2 doses of PCV 20 at 3 monthsTable 2:Comparison of patients with appropriate response to vaccinationFootnote: * Defined as a 2-fold or greater increase in antibody concentrations for at least 10 of serotypes when comparing the pre- to the postvaccination results. Results Out of the 30 randomized patients, 4 withdrew from trial, 14 received 2 doses of PCV20, and 12 received 1 dose of PCV 20 (Table 1). One patient did not undergo serologic testing at baseline and 3 patients did not at months 1 and 3. Overall, there was a greater response in patients who received 2 doses of PCV20 at 1 and 3 months (Figure 1 and 2). On univariate analysis, the difference at 1 month was significant for serotypes 3, 14, 19F, 22F, 10A, 11A and 9V. At 3 months, only serotypes 3 had a statistically significant difference. Patients with higher IgG levels and absolute lymphocyte count (ALC) at time of enrollment had greater humoral responses to PCV20 vaccination (Table 2). Conclusion We report an overall greater humoral response to 2 doses of PCV20 compared to 1 in lymphoma survivors at 1 and 3 months from vaccination. IgG levels and ALC were associated with humoral responses. Disclosures Roy F. Chemaly, MD, MPH, FIDSA, FACP, FESCMID, ADMA Biologics: Advisor/Consultant|AiCuris: Advisor/Consultant|AiCuris: Grant/Research Support|Ansun Biopharma: Advisor/Consultant|Ansun Biopharma: Grant/Research Support|Assembly Bio: Advisor/Consultant|Astellas: Advisor/Consultant|Eurofins Viracor: Advisor/Consultant|Eurofins Viracor: Grant/Research Support|Genentech: Grant/Research Support|Gilead: Advisor/Consultant|InflaRX: Advisor/Consultant|IntegerBio: Advisor/Consultant|Karius: Advisor/Consultant|Karius: Grant/Research Support|Merck/MSD: Advisor/Consultant|Merck/MSD: Grant/Research Support|Moderna: Advisor/Consultant|Oxford Immunotec: Advisor/Consultant|Pfizer: Advisor/Consultant|Shionogi: Advisor/Consultant|Takeda: Advisor/Consultant|Takeda: Grant/Research Support|Tether: Advisor/Consultant Fareed Khawaja, MBBS, Eurofins Viracor: Grant/Research Support|MERCK: Grant/Research Support|Symbio: Grant/Research Support