Study details
Previous studies have shown that some patients with cancer have prolonged responses to SARS-CoV-2 infection, with ongoing immune dysregulation, inefficient seroconversion, and prolonged viral shedding.
There are few data, however, on how these patients respond to COVID-19 vaccination. The authors point out that, among the 18,860 individuals who received the Pfizer vaccine during its development trials, “none with an active oncological diagnosis was included.”
To investigate this issue, they launched the SARS-CoV-2 for Cancer Patients (SOAP-02) study.
The 151 patients with cancer who participated in this study were mostly elderly, the authors noted (75% were older than 65 years; the median age was 73 years). The majority (63%) had solid-tumor malignancies. Of those, 8% had late-stage disease and had been living with their cancer for more than 24 months.
The healthy control persons were vaccine-eligible primary health care workers who were not age matched to the cancer patients.
All participants received the first dose of vaccine; 31 (of 151) patients with cancer and 16 (of 54) healthy control persons received the second dose on day 21.
The remaining participants were scheduled to receive their second dose 12 weeks later (after the study ended), in line with the changes in the national guidelines.
The team reported that, approximately 21 days after receiving the first vaccine dose, the immune efficacy of the vaccine was estimated to be 97% among healthy control persons vs. 39% for patients with solid tumors and only 13% for those with hematologic malignancies (P < .0001 for both).
T-cell responses, as assessed via interferon-gamma and/or interleukin-2 production, were observed in 82% of healthy control persons, 71% of patients with solid tumors, and 50% of those with hematologic cancers.
Vaccine boosting at day 21 resulted in immune efficacy of 100% for healthy control persons and 95% for patients with solid tumors. In contrast, only 43% of those who did not receive the second dose were seropositive 2 weeks later.
Further analysis suggested that participants who did not have a serologic response were “spread evenly” across different cancer types, but the reduced responses were more frequent among patients who had received the vaccine within 15 days of cancer treatment, especially chemotherapy, and had undergone intensive treatments.
The SOAP study is sponsored by King’s College London and Guy’s and St. Thomas Trust Foundation NHS Trust. It is funded from grants from the KCL Charity, Cancer Research UK, and program grants from Breast Cancer Now. The investigators have disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.