Poor prognostic significance of Mycobacterium tuberculosis infection during bortezomib-containing chemotherapy in patients with multiple myeloma

BACKGROUND Bortezomib administration leads to a transient decrease in CD4(+) T cells, increasing the susceptibility to opportunistic infections. The activation and proliferation of CD4(+) T cells are particularly important in the host's defense against tuberculosis infection. The aim of this study was to determine the incidence and clinical significance of tuberculosis infection in patients with multiple myeloma (MM) treated with a bortezomib-containing regimen. METHODS We retrospectively investigated the incidence of Mycobacterium tuberculosis in 115 patients with MM who were given a bortezomib-containing regimen and studied the disease prognosis. RESULTS All patients received chemotherapy prior to bortezomib administration, and the median duration from diagnosis to bortezomib administration was 12.4 months (range, 0.2-230). We diagnosed tuberculosis in 8 patients (8/115, 7%): 7 patients had a pulmonary granulomatous lesion prior to chemotherapy and 1 developed reactivation of tuberculosis, but none of them died of uncontrolled tuberculosis infection. In 50% of patients with tuberculosis, bortezomib-containing therapy was interrupted. This resulted in significantly lower response rates to the bortezomib-containing therapy (P<0.05) and significantly shorter overall survival times amongst tuberculosis vs. non-tuberculosis patients (P=0.017). CONCLUSION Tuberculosis infection was not uncommon among the patients with MM who were treated with bortezomib-containing therapy, and tuberculosis infection in these patients resulted in an interruption of bortezomib administration, which significantly affected patient outcomes. Therefore, early diagnosis and treatment of tuberculosis infection are critical to avoid worsening outcomes in such patients.