PB2265: OUTCOMES OF COVID-19 INFECTION IN PATIENTS WITH B AND PLASMA CELL MALIGNANCIES DURING THE THIRD WAVE IN ARGENTINA: A SINGLE CENTER EXPERIENCE

Abstract

Background: The global COVID-19 pandemic caused by SARS-CoV-2 is still ongoing. The third wave arrived in Argentina in mid-December 2021 with Omicron variant as the dominant strain representing 84% of sequenced cases. Patients (pts) with hematologic malignancies (HM) have an increased risk of severe COVID-19 due to their immunosuppressed condition secondary to both underlying disease and subsequent treatment, and lower rates of seroconversion after vaccination. Omicron variant shows an unprecedented degree of neutralizing antibody escape and may require a higher level of anti-spike antibodies to prevent severe COVID-19. Aims: To describe characteristics and outcomes of pts with HM and COVID-19 treated in our hospital during the third wave. Methods: Observational, descriptive and retrospective study of adult pts with chronic lymphocytic leukemia, non-Hodgkin B cell lymphoma and multiple myeloma with confirmed COVID-19 infection between 15th Dec 2021 and 7th Feb 2022. We included pts with active disease or who had received anticancer therapy within the last year of COVID-19 infection. Complete vaccination schedule was defined as tree doses or two if the last shot was applied between 14 days and 5 months of COVID-19 infection. IgG levels against SARS-CoV-2 spike protein were analyzed with Abbott SARS-CoV-2 IgG II Quant-test with ≥50 AU/ml as a threshold for positivity. Pts received convalescent plasma according to physician criteria. Results: A total of 38 pts were included. Mean age was 63 years, 60.5% were males and 55% had ≥1 comorbidity. Eleven pts had chronic lymphoid leukemia, 10 indolent B cell lymphoma, 7 aggressive B cell lymphoma and 10 multiple myeloma. Concerning disease status, 39.5% were in complete or partial response, 42.1% had progressive or stable disease and 18.4% were on watch and wait. Nearly half of the pts had received a B-cell-depleting monoclonal antibody-based regimen: Rituximab (n=13), Daratumumab (n=4) or Obinutuzumab (n=1); the other half: other anti-myeloma therapy (n=5), chemotherapy (n=3), Ibrutinib (n=3), Venetoclax (n=2) or were untreated (n=7). Twenty-eight were fully vaccinated, 8 had incomplete vaccination and only one was unvaccinated. Heterologous vaccine regimens were used in 21 pts, most frequently vector-based plus mRNA vaccine (n=12). Regarding the last shot, the majority received vector-based vaccine (AstraZeneca Oxford n=21; Sputnik V n=4), followed by mRNA vaccine (BioNTech/Pfizer n=7, Moderna n=4) and inactivated vaccine (Sinopharm n=1). The median time from the last dose and COVID-19 diagnosis was 77 days (IQR 40.5-177). At the time of COVID-19 diagnosis, IgG anti-spike antibodies were measured in 16 pts, 4 were no responders and the median level for those who did response was 176,6 AU/ml (IQR 86,6-879,8). Fourteen required hospital admission, among which 8 needed oxygen support and 5 were admitted to ICU. Twelve pts were treated with convalescent plasma, 9 received corticosteroids and 1 tocilizumab. With a median follow up of 42 days, the overall mortality rate was 7.9% (n=3). Follow-up swabs were performed in 21 pts, 18 converted to negative after a mean of 23.4 days (SD +/- 8,4) from the first nasal swab and in 3 it still remained positive after 37, 40 and 45 days respectively. Summary/Conclusion: This report sheds light into outcomes of pts with HM infected with Omicron variant. Our findings show lower fatality rate than reported in previous waves, but still higher than the general vaccinated population. This might be explained because even if fully vaccinated, responsive patients fail to achieve protective levels of anti-spike antibodies.