Pb2575: high incidence of respiratory tract infections following covid-19 waves in patients with plasma cell dyscrasias

Topic: 30. Infections in hematology (incl. supportive care/therapy) Background: Patients (pts) with plasma cell dyscrasias are at high risk of complications from viral infections due to T cell depletion and the immunosuppressive status caused by the disease and its treatments. Respiratory tract infections (RTIs) of all grades are frequent, ranging from 20% to 50% in clinical trials and epidemiological studies Aims: We aimed to analyze the incidence of RTIs after COVID-19 waves in pts treated with combination therapies Methods: We conducted a retrospective, single-center analysis to evaluate the impact of RTIs on multiple myeloma (MM) pts at Hematology Department of IRCCS San Raffaele Hospital in Milan. We collected data on all consecutive pts on active treatment, symptomatic RTIs and their outcomes during winter season from Oct 1st 2022 to Feb 10th 2023, and compared them to the same seasonal waves from Oct 2018 onwards. Pts were treated according to institutional standard of care, upon written informed consent for chemotherapy, off label therapies and use of medical records for research. Results: We analyzed 568 pts on active treatment who were at risk of infection in different years. The cumulative incidence of all grades RTI was 5/70 (7%) in 2018/19, 13/95 (13.7%) in 2019/20, no cases (0/119) in 2020/21, 4/145 (2.7%) in 2021/22, and 30/139 (21.6%) in 2022/23. In the 2022-2023 wave, 27 pts experienced a RTI with positive swab for a total of 30 infective events. Median age is 66 years (range 40-77 years). All except one pt with AL amyloidosis, had MM. 10 (37%) and 4 (15%) pts displayed a moderate and severe Charlson Comorbidity Index, respectively. 13 (48%) pts underwent I line in different phases of therapy: 7 Daratumumab (Dara)-bortezomib-thalidomide and dexamethasone(D), 2 autologous stem cell transplant (SCT) with Melphalan200 and 4 lenalidomide maintenance. 7 (26%) pts were in II line treated with triplets [2 Isatuximab-lenalidomide-D (RD), 3 DaraRD and 2 carfilzomib-RD] and 6 (22%) pts were in >III line (1 Isatuximab-carfilzomib-D, 2 DaraRD, 1 Isatuximab-pomalidomide-D and 1 pt underwent an allogenic SCT). The pt with AL amyloidosis was on Dara. The majority of pts previously underwent autologous [18 (67%)] and allogenic SCT [4 (15%)]. All pts were vaccinated for seasonal influenza and on acyclovir prophylaxis. 11 (41%) pts received periodical intravenous immunoglobulin (IV Ig) as supportive therapy for immunoparesis during winter season. Positive swabs detected different viruses: 4 Coronavirus OC43/HKV1, 1 Influenza A, 3 Metapneumovirus, 3 parainfluenza, 8 rhinovirus and 11 respiratory syncytial virus (RSV). There were 5 RSV co-infections with rhinovirus (2) and 1 each for metapneumovirus, Coronavirus OC43/HKV1 and parainfluenza and 3 RSV-superinfection (2 pulmonary aspergillosis, 1 bacterial pneumonia). 28 cases (93%) of RTI were mild and did not require hospitalization. 2 pts with RSV upper RTI (URTI) progressed to lower RTI (LRTI) during the aplastic phase of autoSCT and received IV Ig and off-label ribavirin. 7 pts were treated with IV Ig for URTI. After a median follow-up of 62 days (range 19-134 days), all pts improved and solved the RTI. In 27 (90%) cases there was a delay in anti-MM therapy that was resumed after a median of 7 days without progression of disease or dose reductions. Summary/Conclusion: This analysis suggests that the reduction in social measures for Sars-CoV2 pandemic led to an increase in cases of RTI in patients treated for MM. However, all the infections were mild and did not impact the response to anti-MM therapy. Further analysis may help develop a risk-stratified approach to prevention measures and assess the role of IV Ig in the winter period Keywords: Infection, Multiple myeloma