Background: Patients (pts) with cancer have a high risk of venous thromboembolic (VTE) complications, further enhanced by anti-cancer treatments, specifically hormonal therapies, targeted therapies (VEGF inhibitors, other TKIs) and immune checkpoint inhibitors (ICIs). We hypothesized that high-risk therapies would predispose pts with cancer and COVID-19 to higher risk of VTE complications. Methods: CCC19 is the largest international registry (NCT04354701) recording outcomes of pts with cancer and COVID-19. The registry was queried for hospitalized pts who developed VTE and received systemic cancer treatment in the year prior to COVID-19. Incidence of VTE was analyzed as the primary endpoint; 30-day any cause mortality & need for ICU admission at baseline were secondary endpoints in pts with and without VTE respectively. Pts were stratified by treatment type and time from last treatment dose: <2 wk, 2-4 wk, 1-3 months (mos), 3-12 mos. Results: As of February 9th 2021, 4217 hospitalized pts with complications data were present in the registry. 1867 (44%) pts had received systemic anti-cancer therapy within the year prior to COVID-19 and were analyzed. There were a total of 186 (10%) VTE events. Of these, VTE incidence was 141 (10.5%) in pts with solid tumors and 57 (9%) in pts with hematologic malignancies. Overall 30-day mortality was 20% and 22% in pts with and without VTE respectively, while direct admission to ICU at presentation was seen in 17% and 10% of pts with and without VTE, respectively. Treatment timing and drug exposures are below (Table). Receipt of systemic anti-cancer treatment within 3 mos vs 3-12 mos was associated with increased rate of VTE, OR 2.44, 95% CI 1.18-5.84, p=0.011 (univariate Fisher test). Conclusions: We describe the incidence of VTE events in pts with cancer and COVID-19 with recent systemic cancer therapy. ICI and VEGFi were associated with numerically higher rates of VTE; other examined drugs and drug classes were not. Timing of therapy appears to modify risk of VTE. Although retrospective, with possible selection and confounding biases, our analysis suggests that factors other than anti-cancer drug exposures may drive VTE events in this population.

¹Specific drugs were captured from free text, which was not recorded for all patients.