Tocilizumab, tacrolimus and methotrexate for the prevention of acute graft- versus-host disease: low incidence of lower gastrointestinal tract disease

Abstract

We conducted a phase 2 study in which patients undergoing allogeneic hematopoietic stem cell transplantation received tocilizumab in addition to standard immune suppression with tacrolimus and methotrexate for graft-versus-host disease prophylaxis. Thirty-five patients were enrolled between January 2015 and June 2016. The median age of the cohort was 66 (range: 22-76). All patients received busulfan-based conditioning, and were transplanted with human leukocyte antigen-matched related or matched unrelated bone marrow or peripheral stem cell grafts. The cumulative incidences of grades II-IV and III-IV acute graft-versus-host disease were 14% (95% CI 5-30) and 3% (95% CI 0-11) at day 100, and 17% (95% CI 7-31) and 6% (95% CI 1-16) at day 180, respectively. Notably, there were no cases of graft-versus-host disease of the lower gastrointestinal tract within the first 100 days. A comparison to 130 matched controls who only received tacrolimus and methotrexate demonstrated a lower cumulative incidence of grades II-IV acute graft-versus-host disease (17% versus 45%, P=0.003) and a significant increase in grades II-IV acute graft-versus-host disease-free survival at six months (69% versus 42%, P=0.001) with tocilizumab, tacrolimus and methotrexate, which was the primary endpoint of the study. Immune reconstitution was preserved in patients treated with tocilizumab, tacrolimus and methotrexate, as T-cell and B-cell subsets recovered to near normal levels by 6-12 months post-transplantation. We conclude that tocilizumab has promising activity in preventing acute graft-versus-host disease, particularly in the lower gastrointestinal tract, and warrants examination in a randomized setting.

Figure 1.

Engraftment, GvHD, disease-free survival, and overall survival. (A). Cumulative incidence of achieving an absolute neutrophil count >500/mm³ for three consecutive days. (B). Cumulative incidence of patients that achieved an unsupported platelet count > 20,000/mm³. Five patients never dropped their platelet count below 20,000. (C,D). Cumulative incidence of grades II-IV and grades III-IV aGvHD. (E). Cumulative incidence of grades II-IV aGvHD in patients that received myeloablative (MA) versus reduced intensity (RIC) preparative regimens. (F). Cumulative incidence of NIH-defined cGvHD. (G) Probability of disease-free survival and (H) overall survival in patients that received Toc/Tac/MTX as GvHD prophylaxis. Dashed gray lines indicate 95% confidence interval bands.

Figure 2.

Cytokine levels in control population that received tacrolimus and methotrexate for GvHD prophylaxis. Concentration of IL-6, sIL-6R, IL-2, IL-4, IL-10, IL-17, TNF-α, and IFN-g in the serum of patients (n=11) who received Tac/MTX for the prevention of aGvHD prior to the start of conditioning, and at days 7, 14 and 28. *P<0.05, ***P<0.001. IL: interleukin; sIL: soluble interleukin; TNF-α: tumor necrosis factor α; IFN-γ: interferon γ.

Figure 3.

Effect of tocilizumab administration on interleukin 6 and soluble interleukin 6 receptor levels based on conditioning regimen. (A). Concentration of IL-6 in the serum from patients that were treated with tocilizumab and received myeloablative or reduced intensity conditioning. (B). Concentration of soluble IL-6 receptor in the serum from patients that were treated with tocilizumab and received myeloablative or reduced intensity conditioning. ***P<0.001. IL: interleukin; sIL: soluble interleukin; RIC: reduced intensity conditioning.

Figure 4.

Comparative analysis of serum cytokine production in tocilizumab-treated versus patients that received Tac/MTX only. Concentration of IL-6, sIL-6R, IL-2, IL-4, IL-10, IL-17, IFN-γ, and TNF-α in the serum of patients that were treated with Toc/Tac/MTX (●, n=35) or Tac/MTX (control) (○, n=11) for the prevention of aGvHD prior to the start of conditioning and at days 7, 14 and 28. *P<0.05, **P<0.01, ***P<0.001. IL: interleukin; sIL: soluble interleukin; TNF-α: tumor necrosis factor α; IFN-γ: interferon γ.

Figure 5.

Reconstitution of major lymphocyte subsets in patients who received tocilizumab for GvHD prophylaxis. (A,B). The absolute number of cells per mm³ (i.e., microliter) is shown in panel A, and the percentage of the gated cells is shown in panel B. Data are shown for individual patients together with the median and 25^th and 75^th quartiles (red bars). Gray shading represents the upper and lower range expected for healthy control subjects. Samples were obtained at one month (n=33), three months (n=29), six months (n=22), and 12 months (n=13). Lymphocytes were gated on total CD45⁺ white blood cells, and all other subsets were gated on lymphocytes. NK: natural killer.

Figure 6.

GvHD and transplant outcomes in patients treated with tocilizumab versus a matched CIBMTR control population. (A). Cumulative incidence of grades II-IV aGvHD in patients treated with tocilizumab versus the matched control cohort. (B). Probability of grades II-IV aGvHD-free survival. (C). Cumulative incidence of cGvHD, (D) transplant-related mortality, and (E) relapse. (F) Probability of disease-free survival in patients treated with tocilizumab versus the matched control cohort. Toc: tocilizumab: Tac: tacrolimus; MTX: methotrexate.