Immunologic Response to COVID-19 Vaccination in Patients with Ovarian Cancer Receiving PARP Inhibitors

The findings of a prospective study suggest that immunologic response to SARS-CoV-2 vaccination is lower among patients with ovarian cancer who are receiving treatment compared with healthy volunteers, indicating that such patients should maintain precautions against COVID-19 despite vaccination.

A prospective study compared the immunologic response to SARS-CoV-2 vaccination among patients with ovarian cancer who received systemic therapy versus healthy volunteers. The results of the study were published in the October 2021 issue of Vaccines.

The study prospectively enrolled both patients with cancer receiving poly (ADP-ribose) polymerase (PARP) inhibitors and healthy volunteers. The kinetics of anti–SARS-CoV-2 neutralizing antibodies after COVID-19 vaccination were assessed. Baseline demographics, comorbidities, and the levels of neutralizing antibodies were compared between the 2 groups.

A total of 36 patients with ovarian cancer who received PARP inhibitor therapy (median age, 64 years) were enrolled in the study; 160 controls (healthy volunteers) were also enrolled with similar characteristics (median age, 63 years). Among the patients with ovarian cancer, 20 received olaparib, 15 received niraparib, and 1 received rucaparib. In terms of vaccination received, 30 of 36 patients received a PARP inhibitor, and 130 of 160 healthy volunteers in the control group received an mRNA vaccine; whereas 6 of 36 patients and 30 of 160 controls received the AZD1222 vaccine; each participant received 2 doses of the assigned vaccine.

No new safety issues were reported in the study population; the most frequent adverse events included pain at the injection site, fever, and fatigue. However, the levels of SARS-CoV-2 neutralizing antibodies were significantly lower in the patients with cancer receiving PARP inhibitor therapy, compared with the matched healthy volunteers, up to day 30 after the second dose. Although no significant difference in neutralizing antibody titers were noted on day 1 between the 2 groups, on day 22, 10 (27.8%) patients receiving a PARP inhibitor had neutralizing antibody titers ≥30%, compared with 119 (74.4%) in the control group (P <.001). The lower neutralizing antibody titers in treated patients with ovarian cancer receiving a PARP inhibitor compared with healthy controls persisted for 1 month after the second vaccination dose (83.6% vs 92.9%, respectively; P <.001). Preclinical evidence suggests that PARP inhibitors affect immune cells by attenuating SARS-CoV-2–induced inflammatory responses and cytokine storms, and reducing lung fibrosis, thus supporting its potential use in the treatment of COVID-19.

These results suggest that immunologic response to SARS-CoV-2 vaccination was lower among patients with cancer receiving PARP inhibitor treatment compared with a healthy population, indicating that such patients should maintain precautions against COVID-19 despite vaccination. The researchers recommend the administration of a third dose after a certain time among patients with ovarian cancer receiving PARP inhibitor therapy, to generate optimal immunity against the SARS-CoV-2 virus.

Source: Liontos M, Terpos E, Markellos C, et al. Immunological response to COVID-19 vaccination in ovarian cancer patients receiving PARP inhibitors. Vaccines (Basel). 2021;9:1148.