Limited efficacy of tocilizumab in adult patients with secondary hemophagocytic lymphohistiocytosis: a retrospective cohort study

Abstract

Background Interleukin (IL)-6 is one of the key cytokines in the pathogenesis of secondary hemophagocytic lymphohistiocytosis (sHLH); however, the efficacy and safety of tocilizumab (TCZ), a monoclonal IL-6 receptor antibody, in patients with sHLH is uncertain. Methods/Results This study included 64 adult patients who were diagnosed with sHLH based on the HLH-2004 criteria. Patients were classified into two groups based on treatment regimen at baseline: tocilizumab (TCZ group, n = 8) versus other treatments (control group), including HLH-2004 protocol (n = 35), chemotherapy (n = 7), glucocorticoid alone (n = 8), and with other immunosuppressants (n = 6). Primary outcome was overall 8-week survival. Baseline characteristics between the two groups were comparable. At day 56, one patient (12.5%) in the TCZ group and twenty-eight patients (51.9%) in the control group survived. Univariable and multivariable Cox proportional hazard analysis showed that TCZ significantly increased the risk of death (adjusted hazard ratio 5.55; 95% CI 2.13-14.49). The complete or partial response rate at day 14 was 44.6% in the control group, and nil in the TCZ group. In contrast, infectious complications occurred more frequently in the TCZ group than in the control group (14.3% vs. 50.0%). Conclusion Our results suggest that tocilizumab has limited efficacy in treating adult patients with sHLH and could increase the risk of infectious complications compared to the conventional treatments.