Nadir lymphocytopenia as a risk factor of bloodstream infection during molecular targeting pharmacotherapy in...

Molecular targeting pharmacotherapy (MTP) with proteasome inhibitors and immunomodulatory drugs has led to a remarkable improvement in the effectiveness of multiple myeloma (MM) therapy. However, the effect of MTP on the occurrence of infections in patients with MM remains unclear. We aimed to identify the incidence of and risk factors for bloodstream infection (BSI) in patients with MM undergoing MTP.

We conducted a retrospective cohort study. We reviewed the medical records of 108 inpatients with MM at the National Defense Medical College Hospital between January 2010 and January 2017. Univariate and multivariate analyses were conducted to identify risk factors for BSI.

The incidence of BSI in patients with MM receiving MTP (n = 188) was 6.9%, which was significantly lower than the 52.6% in patients receiving cytotoxic chemotherapy (n = 57). We found that the most important risk factor for BSI in patients receiving MTP was lymphocytopenia at nadir (< 200/µL). In contrast, the risk factor for BSI in patients receiving cytotoxic chemotherapy was the number of regimens performed.

Our study suggests that the incidence of BSI is lower in patients with MM receiving MTP than in those receiving cytotoxic chemotherapy and that lymphocytopenia at nadir may be a risk factor for BSI in patients with MM receiving MTP. Since previous clinical trials with MTP showed that the frequency of myelosuppression and infections was high in the Japanese population, these findings might provide novel insights into MTP for Japanese patients with MM.
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