Outcomes Following Intolerance to Tacrolimus/Sirolimus Graft-Versus-Host Disease Prophylaxis for Allogeneic Hematopoietic Cell Transplantation

Evaluation of Immunosuppression Levels and Risk of Graft-Versus-Host Disease in Allogeneic Blood or Marrow Transplantation With Post-Transplantation Cyclophosphamide

Post-transplantation cyclophosphamide (PTCy) is standard graft-versus-host disease (GVHD) prophylaxis for allogeneic blood or marrow transplantation (alloBMT), although optimal therapeutic levels of immunosuppression (IS) therapy combined with PTCy remain contested. Previously, with tacrolimus and methotrexate GVHD prophylaxis, week 1 tacrolimus levels >12 ng/mL were associated with a decreased incidence of grade 2 to 4 acute GVHD (aGVHD). We evaluated if associations between aGVHD and early IS levels were observed amongst patients receiving PTCy. This retrospective single-center study consisted of 349 patients who received PTCy and mycophenolate mofetil, with either tacrolimus (n = 185) or sirolimus (n = 164) from September 1, 2017, to September 30, 2019. The median age of patients receiving tacrolimus and sirolimus were 58 and 54 years, respectively. The primary diagnosed diseases for both cohorts were acute myeloid leukemia, acute lymphoblastic leukemia, myelodysplastic syndrome, and lymphoma. While most patients receiving tacrolimus were bone marrow graft sourced (78.4%), the majority of patients receiving sirolimus were peripheral blood sourced (80.5%). All patients were transplanted with FluCyTBI as the conditioning regimen. The primary outcome was grade 2 to 4 aGVHD incidence at 150 days post alloBMT between weekly IS levels <10 ng/mL versus ≥10 ng/mL throughout the 4 weeks post-alloBMT. Secondary endpoints included moderate to severe chronic GVHD (cGVHD) incidence, median overall survival (OS), relapse-free survival (RFS), and GVHD-free relapse-free survival (GRFS) at 2 years and the correlation between weekly IS levels <10 ng/mL versus ≥10 ng/mL throughout 4 weeks post-alloBMT. Patients receiving tacrolimus were compared to others in the tacrolimus cohort, and similarly for sirolimus. No correlation was found between IS levels at any individual week and cumulative aGVHD incidence for either tacrolimus or sirolimus. In the sirolimus cohort, no correlation for moderate to severe cGVHD was observed. However, at week 4, patients in the tacrolimus cohort with levels ≥10 ng/mL experienced significantly higher incidence of moderate to severe chronic GVHD than patients with weekly levels <10 ng/mL (20% versus 8%, P < .001). When evaluating survival outcomes, post-alloBMT week 1 tacrolimus levels ≥10 ng/mL were associated with decreased OS (HR 3.84, 95% CI [1.16 to 12.67]; P = .027), but no correlation was seen in RFS (HR 1.62, 95% CI [0.56 to 4.72]; P = .377), or GRFS (HR 1.56, 95% CI [0.89 to 2.74]; P = .124). Post-alloBMT week 1 sirolimus ≥10 ng/mL levels were associated with decreased OS (HR 2.74, 95% CI [1.37 to 5.48]; P = .004) and GRFS (HR 1.93, 95% CI [1.19 to 3.12]; P = .007), but not RFS (HR 1.60, 95% CI [0.78 to 3.30]; P = .202). Overall, early IS levels in patients receiving PTCy-based GVHD prophylaxis did not correlate with aGVHD incidence, although IS levels ≥10 ng/mL were associated with compromised outcomes. Targeting IS levels <10 ng/mL may be optimal when using PTCy-based GVHD prophylaxis.

Corticosteroids as graft-versus-host disease prophylaxis for allogeneic hematopoietic cell transplant recipients with calcineurin inhibitor intolerance

BACKGROUND AIMS

Although calcineurin inhibitors (CNIs) have a well-established role in the prevention of graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplantation (HCT), their use can be limited by significant toxicities, which may result in premature treatment discontinuation. The optimal management of patients with CNI intolerance is unknown. The objective of this study was to determine the effectiveness of corticosteroids as GVHD prophylaxis for patients with CNI intolerance.

METHODS

This retrospective single-center study included consecutive adult patients with hematologic malignancies who underwent myeloablative peripheral blood allogeneic HCT with anti-thymocyte globulin, CNI, and methotrexate GVHD prophylaxis in Alberta, Canada. Multivariable competing-risks regression was used to compare cumulative incidences of GVHD, relapse, and non-relapse mortality between recipients of corticosteroid versus continuous CNI prophylaxis, and multivariable Cox proportional hazards regression was applied to compare overall survival, relapse-free survival (RFS) and moderate-to-severe chronic GVHD and RFS.

RESULTS

Among 509 allogeneic HCT recipients, 58 (11%) patients developed CNI intolerance and were switched to corticosteroid prophylaxis at median 28 days (range 1-53) after HCT. Compared with patients who received continuous CNI prophylaxis, recipients of corticosteroid prophylaxis had significantly greater cumulative incidences of grade 2-4 acute GVHD (subhazard ratio [SHR] 1.74, 95% confidence interval [CI] 1.08-2.80, P = 0.024), grade 3-4 acute GVHD (SHR 3.22, 95% CI 1.55-6.72, P = 0.002), and GVHD-related non-relapse mortality (SHR 3.07, 95% CI 1.54-6.12, P = 0.001). There were no significant differences in moderate-to-severe chronic GVHD (SHR 0.84, 95% CI 0.43-1.63, P = 0.60) or relapse (SHR 0.92, 95% CI 0.53-1.62, P = 0.78), but corticosteroid prophylaxis was associated with significantly inferior overall survival (hazard ratio [HR] 1.77, 95% CI 1.20-2.61, P = 0.004), RFS (HR 1.54, 95% CI 1.06-2.25, P = 0.024), and chronic GVHD and RFS (HR 1.46, 95% CI 1.04-2.05, P = 0.029).

CONCLUSIONS

Allogeneic HCT recipients with CNI intolerance are at increased risks of acute GVHD and poor outcomes despite institution of corticosteroid prophylaxis following premature CNI discontinuation. Alternative GVHD prophylaxis strategies are needed for this high-risk population.