Ultra-short course sirolimus contributes to effective GVHD prophylaxis after reduced-intensity allogeneic hematopoietic cell transplantation

Pharmacokinetics, Pharmacodynamics, and Pharmacogenomics of Immunosuppressants in Allogeneic Hematopoietic Cell Transplantation: Part II

Part I of this article included a pertinent review of allogeneic hematopoietic cell transplantation (alloHCT), the role of postgraft immunosuppression in alloHCT, and the pharmacokinetics, pharmacodynamics, and pharmacogenomics of the calcineurin inhibitors and methotrexate. In this article (Part II), we review the pharmacokinetics, pharmacodynamics, and pharmacogenomics of mycophenolic acid (MPA), sirolimus, and the antithymocyte globulins (ATG). We then discuss target concentration intervention (TCI) of these postgraft immunosuppressants in alloHCT patients, with a focus on current evidence for TCI and on how TCI may improve clinical management in these patients. Currently, TCI using trough concentrations is conducted for sirolimus in alloHCT patients. Several studies demonstrate that MPA plasma exposure is associated with clinical outcomes, with an increasing number of alloHCT patients needing TCI of MPA. Compared with MPA, there are fewer pharmacokinetic/dynamic studies of rabbit ATG and horse ATG in alloHCT patients. Future pharmacokinetic/dynamic research of postgraft immunosuppressants should include '-omics'-based tools: pharmacogenomics may be used to gain an improved understanding of the covariates influencing pharmacokinetics as well as proteomics and metabolomics as novel methods to elucidate pharmacodynamic responses.

Sirolimus as Long-term Graft-versus-host-disease Prophylaxis in Haploidentical Hematopoietic Stem Cell Transplant Recipients for Non-malignant Disorders is Associated with High Incidence of Acneiform Lesions

Background:

Sirolimus has provided the option for calcineurin inhibitor (CNI)-free immunosuppressive therapy in both solid organ transplant (SOT) and hematopoietic stem cell transplantation (HSCT). However, long-term use of sirolimus has been reported to be associated with a high incidence of cutaneous side effects in SOT, particularly acneiform lesions.

Materials and Methods:

We studied the incidence of acneiform lesions and the risk factors in 41 HSCT recipients between ages 4 and 64 years, undergoing HSCT for malignant (n = 29) and non-malignant diseases (n = 12) from haploidentical family donors.

Results:

Seven patients developed acneiform lesions at the median of 85 days (range, 45–105 days). Acneiform lesions occurred in 6/11 patients on sirolimus and in only 1/30 patients not receiving sirolimus (P = 0.001). This was more frequent in patients with non-malignant disorders (5/12 versus 2/29, P = 0.01) and those receiving graft from female donors (7/23 versus 0/18, P = 0.01).

Conclusions:

Despite being frequently reported in SOT, this is the first such report in HSCT. Our study suggests that prolonged use of sirolimus might be associated with high incidence of acneiform lesions in haploidentical HSCT recipients with non-malignant diseases, particularly in those receiving graft from a female donor. We discuss the possible reasons for these findings and the putative mechanism of acneiform lesions in these patients

[Allogeneic stem-cell transplantation in adults 1985-2012: results and development]

BACKGROUND

Allogeneic stem cell transplantation (ASCT) has been a treatment option for patients with serious diseases of the blood and haematopoietic organs in Norway since 1985. Such treatment is potentially curative for selected patients who have a relatively short predicted survival with other treatment modalities. This article summarises the experience and results from ASCT at Oslo University Hospital Rikshospitalet.

MATERIAL AND METHOD

The study included all of the 734 adult patients who had undergone allogeneic stem cell transplantation at the Department of Haematology, Rikshospitalet, later Oslo University Hospital Rikshospitalet, from November 1985 to October 2012.

RESULTS

At the time of analysis, altogether 384 patients were alive, and the five and ten-year survival rates were 54% and 48% respectively. The median follow-up time was six years. A total of 339 patients (46%) had developed acute graft-versus-host disease (GvHD), and 250 (73%) of these had GvHD ≥ grade II. Altogether 280 out of 602 patients who lived ≥ 100 days after the transplantation (46.5%) developed chronic GvHD. The most frequent causes of death included recurrence of the initial disease in 116 patients (33.1 %), multi organ failure after transplantation in 88 patients (25.4%), infections in 54 patients (16%) and GvHD in 33 patients (9.4%).

INTERPRETATION

ASCT is a treatment option with a curative potential for patients with serious haematological diseases when other forms of treatment provide few prospects for recovery. The total survival rate in our study is in accordance with international results for the same time period, and the indications have consistently been in line with what is accepted internationally.

Rapamycin-resistant effector T-cell therapy

Pharmacologic inhibition of the mechanistic target of rapamycin (mTOR) represents a stress test for tumor cells and T cells. Mechanisms exist that allow cells to survive this stress, including suboptimal target block, alternative signaling pathways, and autophagy. Rapamycin-resistant effector T (T-Rapa) cells have an altered phenotype that associates with increased function. Ex vivo rapamycin, when used in combination with polarizing cytokines and antigen-presenting-cell free costimulation, is a flexible therapeutic approach as polarization to T-helper 1 (Th1)- or Th2-type effectors is possible. Murine T-Rapa cells skewed toward a Th2-type prevented graft rejection and graft-versus-host disease (GVHD) more potently than control Th2 cells and effectively balanced GVHD and graft-versus-tumor (GVT) effects. A phase II clinical trial using low-intensity allogeneic hematopoietic cell transplantation demonstrated that interleukin-4 polarized human T-Rapa cells had a mixed Th2/Th1 phenotype; T-Rapa cell recipients had a balanced Th2/Th1 cytokine profile, conversion of mixed chimerism toward full donor chimerism, and a potentially favorable balance between GVHD and GVT effects. In addition, a phase I clinical trial evaluating autologous T-Rapa cells skewed toward a Th1- and Tc1-type is underway. Use of ex vivo rapamycin to modulate effector T-cell function represents a promising new approach to transplantation therapy.

Phase 2 clinical trial of rapamycin-resistant donor CD4+ Th2/Th1 (T-Rapa) cells after low-intensity allogeneic hematopoietic cell transplantation

In experimental models, ex vivo induced T-cell rapamycin resistance occurred independent of T helper 1 (Th1)/T helper 2 (Th2) differentiation and yielded allogeneic CD4(+) T cells of increased in vivo efficacy that facilitated engraftment and permitted graft-versus-tumor effects while minimizing graft-versus-host disease (GVHD). To translate these findings, we performed a phase 2 multicenter clinical trial of rapamycin-resistant donor CD4(+) Th2/Th1 (T-Rapa) cells after allogeneic-matched sibling donor hematopoietic cell transplantation (HCT) for therapy of refractory hematologic malignancy. T-Rapa cell products, which expressed a balanced Th2/Th1 phenotype, were administered as a preemptive donor lymphocyte infusion at day 14 post-HCT. After T-Rapa cell infusion, mixed donor/host chimerism rapidly converted, and there was preferential immune reconstitution with donor CD4(+) Th2 and Th1 cells relative to regulatory T cells and CD8(+) T cells. The cumulative incidence probability of acute GVHD was 20% and 40% at days 100 and 180 post-HCT, respectively. There was no transplant-related mortality. Eighteen of 40 patients (45%) remain in sustained complete remission (range of follow-up: 42-84 months). These results demonstrate the safety of this low-intensity transplant approach and the feasibility of subsequent randomized studies to compare T-Rapa cell-based therapy with standard transplantation regimens.