Autologous CD117+ Progenitor Cell Mobilization for Lung Transplantation

The investigators have developed a new therapy utilizing a stem cell found in the bone marrow that is defined by cell surface expression of the protein "cluster of differentiation antigen 117" (CD117). Studies utilizing these stem cells in a mouse heart transplant model have demonstrated significantly improved survival of transplanted hearts, (as much as more than 5 times that seen with untreated heart transplants). In vitro studies in mice also show that these cells work to inhibit the immune system by inhibiting T cell activation/proliferation by both paracrine (primary) and contact-dependent (lesser) mechanisms. Importantly, these stem cells are taken from the intended transplant recipient (autologous) and since these cells are part of their own body normally (in small numbers); these cells are theoretically without risk to the patient. This is very different from other stem cell therapies, which are taken from the donor and as such put the patient at significant risk of developing potentially life-threatening immune reactions. Because the use of our own stem cells is potentially safe - the rapid study, development, and implementation of autologous CD117 stem cell (SC) therapy in human transplant patients is theoretically possible. Therefore, these cells have high impact potential for the field of tissue and organ transplantation as well as auto-immunity - to potentially improve tissue/cellular engraftment, decrease acute rejection, and/or to promote organ transplant tolerance (lack of rejection despite no concomitant immune-suppression). Prior to full clinical development (efficacy trials in humans), the next step is to develop a safe and efficacious means for obtaining relatively large quantities of these cells from potential human recipients. As bone marrow biopsy for cell capture is not without risk (especially to ill potential lung transplant recipients), the investigators propose to use Plerixafor (Mozobil), a CXC-chemokine receptor 4 (CXCR4)-inhibitor to cause efflux of bone marrow-derived CD117+ cells to the peripheral blood for capture by apheresis/positive selection. If successful, the next step will be to perform initial safety studies in human patients awaiting transplantation and normal controls (not a goal of this initial protocol however). These studies have the potential to lead to large-scale clinical efficacy trials and ultimate indication/implementation for human disease(s).

Primary Outcome Measure: The number of circulating CD117+ cells per milliliter (ml) of peripheral blood at baseline and following Plerixafor (Mozobil) treatment (change in peripheral blood CD117+ cells per ml).

Secondary Outcome Measures:

i.) The number of Plerixafor (Mozobil) related adverse events (AEs). ii.) The number of patients with Plerixafor (Mozobil) related AEs iii.) The number of Plerixafor (Mozobil) related serious adverse events (SAEs). iv.) The number of patients with Plerixafor (Mozobil) related serious adverse events (SAEs).

As listed in the package insert, the most common adverse reactions (≥10%) during hematopoietic stem cell mobilization were: diarrhea (37%), nausea (34%), fatigue (27%), injection site reaction (34%), headache (22%), arthralgia (13%), dizziness (11%), and vomiting (10%). It should be noted that the majority of these occurred in patients also undergoing apheresis.

Outcome Measure Time Frame:

Primary Outcome Measure Time Frame: At baseline and at 8 hours post-Plerixafor (Mozobil) treatment

Secondary Outcome Measures Time Frame:

i.): Continuously for the first 30 minutes post-Plerixafor (Mozobil) treatment, at 1 week post-Plerixafor (Mozobil) treatment, and up to 1 year post treatment.

ii.): For the first 30 minutes post administration, at 1 week post-Plerixafor (Mozobil) treatment and up to 1 year post treatment, at 1 week post-Plerixafor (Mozobil) treatment, and up to 1 year post treatment.

iii.): For the first 30 minutes post administration, at 1 week post-Plerixafor (Mozobil) treatment and up to 1 year post treatment, at 1 week post-Plerixafor (Mozobil) treatment, and up to 1 year post treatment.

iv.): For the first 30 minutes post administration, at 1 week post-Plerixafor (Mozobil) treatment and up to 1 year post treatment, at 1 week post-Plerixafor (Mozobil) treatment, and up to 1 year post treatment.

Primary Study Goals:

To determine whether Plerixafor (Mozobil) will mobilize CD117+ progenitor cells from the bone marrow in patients with chronic lung diseases on the lung transplant waiting list (versus normal controls). We will compare baseline counts of CD117+ cells with cell counts 8 hrs after Plerixafor to determine the efficacy of mobilization.

The primary results will be used to determine the number of rounds of apheresis that may be required to isolate sufficient cells for reinfusion at later timepoints in a future study.

Significance:

If the investigators can mobilize a sufficient number of autologous CD117+ cells, they will eventually re-infuse them at the time of transplant to determine whether we can abrogate acute rejection following human lung transplantation (future study). The investigators believe these are safer than allogeneic stem cells as there is no risk for graft versus host disease (GVHD) with autologous cells.

Hypothesis:

These experiments should demonstrate the effectiveness of CD117+ stem cell mobilization from the bone marrow to the peripheral blood (PB) via CXCR4 antagonism (Plerixafor) and whether end-stage lung disease affects the ability to mobilize stem cells. Additionally, these results will be used to mathematically extrapolate approximately how many rounds of peripheral blood apheresis will be required to attain adequate stem cell numbers for clinical infusion (10e7) for a future study.

Methods:

Experiments will involve taking blood from consented patients awaiting lung transplantation (as well as normal controls) prior to Plerixafor (Mozobil) treatment (240mcg/kg subcutaneously) and then 8 hours after treatment as in Table 1.

TABLE 1:

Patient Category PB baseline analysis Plerixafor (Mozobil) Rx PB analysis 8hrs post-Rx

Awaiting Tx (n=15, 5 chronic obstructive pulmonary disease (COPD), 5 Cystic Fibrosis (CF), and 5 Pulmonary Fibrosis (PF)) CD117 isolation/analysis by Flow Cytometry Yes - 240 mcg/kg CD117+ stem cell isolation/analysis by Flow Cytometry

Normal Control (n=5) CD117 isolation/analysis by Flow Cytometry Yes - 240mcg/kg CD117+ stem cell isolation/analysis by Flow Cytometry