Characteristics and outcome of infectious complications after autologous hematopoietic cell transplantation in multiple myeloma patients

Infections are a significant cause of morbidity and mortality after autologous hematopoietic cell transplantation (AHCT) in multiple myeloma (MM) patients. There has been a rapid advancement and evolution in MM treatment landscape in the last decade. There is limited information on post-AHCT infectious complications among MM patients with or without levofloxacin prophylaxis from developing countries.We performed a retrospective study to explore the incidence, pattern, and clinical outcome of infections following AHCT in MM patients from 2010 to 2019 at our center. Patient-specific, disease-specific, and transplant-specific details were retrieved from the case files. The characteristics of infectious complications (site, intensity, organism, treatment, and outcomes) were analyzed. All patients who underwent transplantation from 2010 to 2016 received levofloxacin antibiotic prophylaxis. Common terminology criteria for adverse events (CTCAE) criteria (v5.0) were used for the grading of infections and regimen-related toxicity. International Myeloma Working Group updated criteria were used for the assessment of disease response before transplant and at day +100.Ninety-five consecutive patients with newly diagnosed multiple myeloma (NDMM) (n = 85), RRMM (n = 7), plasma cell leukemia (n = 2), and Polyneuropathy, Orgaomegaly, Endocrinopathy, Monoclonal gammopathy, skin abnormalities (POEMS) syndrome (n = 1) underwent AHCT during the study period. Their median age was 55 years (range 33-68); 55.8% were males. Immunoglobulin IgG kappa was the most common monoclonal protein (32.6%), International Staging System stage III disease was present in 45.3%, and 84.2% of patients achieved more than very good partial response before AHCT. The median time from diagnosis to AHCT was 10 months (range 4-144). Eighty-nine patients (93.7%) developed fever after AHCT. Fever of unknown focus, microbiologically confirmed infections, and clinically suspected infections were found in 50.5%, 37.9%, and 5.3% of patients, respectively. Clostridiodes difficile-associated diarrhea was observed in eight patients (8.4%). Neutrophil and platelet engraftment occurred after a median of 11 days (range 9-14) and 12 days (range 9-23), respectively. The median duration of hospital stay was 16 days (range 9-29). Only two patients (2.1%) required readmission for infections within 100 days of AHCT. Transplant-related mortality (TRM) in the study population was 4.2% (n = 4). The levofloxacin prophylaxis group (n = 32, 33.7%) had earlier neutrophil engraftment (day +10 vs. day +11) and platelet engraftment (day +11 vs. day +12), but time to fever onset, duration of fever, hospital stay, TRM, and day +100 readmission rates were not significantly different from those of patients without levofloxacin prophylaxis. There was no significant difference in the spectrum of infections between patients with and without levofloxacin prophylaxis. The overall survival and progression-free survival of the study population at 5 years were 72.7% and 64.8%, respectively.This study shows that the incidence of infections and TRM are higher in MM patients from lower-middle income countries after AHCT than in those from developed countries. The majority of such patients lack clinical localization and microbiological proof of infection. There was no significant difference in the spectrum of infections and their outcomes in patients with and without levofloxacin prophylaxis.