Two Doses of PCV20 in Lymphoma Survivors Elicits Greater Humoral Response

There was an overall greater humoral response to 2 doses of the pneumococcal 20-valent conjugate vaccine (PCV20) compared to 1 in survivors of lymphoma at 1- and 3-months following vaccination, according to new data presented at IDWeek 2025 in Atlanta, Georgia.¹

How Does a Second PCV20 Dose Impact Humoral Response?

Investigators conducted an open-label randomized trial of PCV20 in survivors of B-cell lymphoma who received prior anti-CD20 therapy but no cellular therapy at their oncology center. The patients also had to be in complete remission for at least 1 year. Thirty patients were enrolled and randomized 1:1 to receive 1 or 2 doses of PCV20, 1 month apart.¹

A series of measurements were taken throughout the study. At enrollment, pneumococcal serologies were recorded, along with 1 month and 3 months after the initial vaccination. Humoral responses were compared at 1 and 3 months after the first dose; the investigators included only serotypes included in the PCV20 vaccine.¹

Of the randomized patients, 14 received 2 doses of PCV20, 12 received 1 dose of PCV20, and 4 withdrew from the trial. Furthermore, 1 patient did not undergo serological testing at baseline, and 3 patients did not at months 1 and 3. The investigators observed a greater response in patients who received 2 doses of PCV20 at 1 and 3 months.¹

A univariate analysis revealed significant differences in humoral responses at 1 month for serotypes 3, 14, 19F, 22F, 10A, 11A, and 9V. However, at 3 months, only serotype 3 had a statistically significant difference in response. Immunoglobulin G (IgG) and absolute lymphocyte (ALC) counts were higher at the time of enrollment for patients exhibiting greater humoral responses to PCV20 vaccination.¹

Why is Vaccination for Survivors of Lymphoma Important?

Anti-CD20 monoclonal antibodies have transformed the treatment of hematological malignancies. By targeting the CD20 protein, the B cell compartment of these malignancies is successfully depleted and have become a key management strategy in this patient population. However, there is a major risk of infections with these B-cell depleting treatments, both early and later in the course.^1,2

Respiratory infections like pneumococcal disease are especially dangerous. Because these treatments weaken the immune system and deplete B cells—which are critical in preventing infections—there is a limited ability to fight off bacteria like Streptococcus pneumoniae. This makes vaccination a core tenant of prevention for patients undergoing anti-CD20 therapy and is a key area where pharmacists can improve patient outcomes.^1,3

Pharmacists have grown their ability to advocate and counsel patients on the benefits of vaccination. Correspondingly, pharmacists have become members of the care team in myriad health care settings, including for oncology patients. In these settings, pharmacists can discuss with patients the broad protection brought on by pneumococcal vaccination.

REFERENCES

1. Chemaly RF, Ahmed S, Lu H, Nze C, Heredia EA, Trager S. Humoral responses to two versus one dose of pneumococcal conjugate vaccine (PCV20) in lymphoma survivors at 3 months follow up. Poster Session: Vaccines for All Ages. Presented: IDWeek 2025; October 21, 2025; Atlanta, Georgia.

Casan JML, Wong J, Northcott MJ, Opat S. Anti-CD20 monoclonal antibodies: reviewing a revolution. Hum Vaccin Immunother. 2018;14(12):2820-2841. doi:10.1080/21645515.2018.1508624

3. Elsegeiny W, Eddens T, Chen K, Kolls JK. Anti-CD20 antibody therapy and susceptibility to Pneumocystis pneumonia. Infect immune. 2015;83(5):2043-2052. doi:10.1128/IAI.03099-14