C078 | COMPARISON BETWEEN BTKIS, DRC, BR AND OTHER CHEMO-IMMUNOTHERAPEUTIC SCHEMES IN TERMS OF INFECTIONS AND NEED OF HOSPITALIZATION IN WALDENSTRÖM MACROGLOBULINEMIA

Infections are a major source of morbidity and mortality in patients (pts) with Waldenström Macroglobulinaemia (WM). Treatments with Bruton’s Tyrosine Kinase inhibitors (BTKis) have increased, with a reduction on infection rate but data on infection incidence are generally extrapolated from clinical trials, and real-world data are rare. The aim of our study is to describe in a real-world setting the infectious complications in pts with WM treated with chemo-immunotherapy (CIT) or BTKis to evaluate their incidence in first and second line of treatment and to identify additional factors of infectious risk. This retrospective study included 489 WM pts treated since 2008 in 14 Italian haematological centres. Analysing the first line treatment 165 pts were treated with BR (bendamustine-rituximab), 152 DRC (dexamethasone-rituximab-cyclophosphamide), 62 other CIT, 41 only chemotherapy, 51 Rituximab or steroids and 17 BTKis. We registered 113 infections with these infection rates: 32.1% for BR (of whom 34% needed hospitalization), 15.1% for DRC (21.7% hospitalized), 24.2% for other CIT (26.7% hospitalized), 29.3% for chemo (25% hospitalized), 11.5% for Rituximab/steroids (66.7% hospitalized) and 23.5% for BTKis (25% hospitalized). When considering the second line treatment, 204 pts relapsed and were treated according to these schemes: 102 BTKis, 26 BR, 16 DRC, 19 bortezomib based, 22 chemo and 19 Rituximab. We registered 62 infections: 34.3% for BTKis (of whom 28.6% needed hospitalization), 30.8% for BR (37.5% hospitalized), 12.5% for DRC (100% hospitalized), 42.1% for bortezomib (87.5% hospitalized), 31.8% for chemo (28.6% hospitalized), 11.1% for Rituximab (50% hospitalized). Analysing the greater cohorts (Figure 1), we can notice that BTKis pts showed a similar infection rate to BR pts and other CIT pts; only DRC showed a significant reduction in terms of number of infections and severity calculated as need of hospitalization, when comparing it with the other treatments used in first line (p=0.003) and also with BTKis used in second line (p<0.001). Infection rates of each scheme for untreated pts were statistically comparable to the same scheme in relapsed pts. These data need to be analysed also in terms of drug exposure times. So our large retrospective real-life study showed advantages of DRC versus BTKis and other CIT as BR in reducing infections and hospitalization for infections, but a confirmatory analysis with drug exposure comparison will be necessary.