Immune checkpoint inhibitors versus chemotherapy in COVID-19 among cancer patients

The impact of immune checkpoint inhibitors (ICIs) on SARS-CoV-2 infection in cancer patients remains unclear. The aim of the study was to compare the incidence and severity of COVID-19 in patients treated with ICIs versus chemotherapy (CT).

Retrospective study in adult patients with solid tumors who received at least one cycle of ICI or CT during the pandemic. Patients with hematologic malignancies, concomitant autoimmune diseases, or receiving combined ICI + CT were excluded. The primary endpoint was COVID-19 infection rate (PCR or antigen test) according to the type of treatment received. Secondary endpoints included infection severity according to SEIMC criteria. Differences between groups were analyzed using the chi-square test or Fisher's test for categorical variables. Associated factors were assessed using logistic regression.

A total of 235 patients treated with ICI (n = 75) or CT (n = 160) were included. The median age was 64 years and 68.9% were men. Most patients had lung cancer and metastatic disease with good performance status. The overall incidence of COVID-19 was 8.1% (12% ICI vs 6.3% CT, χ² test, p = 0.132). No significant differences were found in infection severity (33.3% ICI vs 66.7% CT, Fisher's test p = 0.370) or mortality (0 deaths ICI vs 3 CT, Fisher's test p = 0.211). Vaccination was associated with a lower risk of infection (OR 0.2, p = 0.003). On the contrary, comorbidity acts as a risk factor (OR 1.6, p = 0.016). No association was found between the duration of ICI treatment and COVID-19 incidence (<3 months [11.1%] vs 3-9 months [22.2%] vs >9 months [66.7%]; χ² test, p = 0.103).

Immunotherapy was not associated with a higher risk or greater severity of COVID-19 compared to chemotherapy. Vaccination showed a significant protective effect, whereas each additional comorbidity increased the risk of infection by 60%. These findings should be interpreted with caution given the limited number of COVID-19 events.