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autologous blood and marrow transplantation - Blog Science ...

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700 Chapter 15: New Avenues<br />

An alternative strategy is to utilize a low-dose, nonmyeloablative, preparative<br />

regimen designed to provide sufficient immunosuppression to achieve engraftment<br />

of an allogeneic <strong>blood</strong> stem cell or <strong>marrow</strong> graft, allowing for development of a<br />

graft-vs.-malignancy effect.<br />

We have evaluated this strategy by using relatively nontoxic, st<strong>and</strong>ard-dose<br />

chemotherapy as a nonmyeloablative preparative regimen for allogeneic <strong>marrow</strong> or<br />

<strong>blood</strong> progenitor cell <strong>transplantation</strong> using chemotherapy regimens active against<br />

the patient's malignancy that are only modestly myelosuppressive without <strong>marrow</strong><br />

<strong>transplantation</strong>. The regimens were selected to be sufficiently immunosuppressive<br />

to prevent graft rejection, allowing engraftment of a <strong>marrow</strong> or <strong>blood</strong> stem cell<br />

allograft which could then produce a GVL effect against susceptible malignancies.<br />

At M.D. Anderson Cancer Center, we performed pilot trials to determine<br />

whether this strategy of nonablative chemotherapy with allogeneic <strong>blood</strong> stem cell<br />

<strong>transplantation</strong> could induce durable engraftment <strong>and</strong> remissions in patients with<br />

hematologic malignancies. We studied this approach in patients who were<br />

ineligible for st<strong>and</strong>ard myeloablative preparative regimens because of advanced<br />

age or comorbidities. We demonstrated that fludarabine or 2-CDA (purine analogs)<br />

containing nonmyeloablative chemotherapy regimens allowed engraftment of<br />

HLA-compatible hematopoietic progenitor cells, <strong>and</strong> extended remissions were<br />

6 0<br />

observed in some patients with recurrent AML or CML.<br />

Indolent lymphoid malignancies are also affected by graft-vs.-malignancy<br />

effects. 22<br />

Fifteen patients with CLL or lymphoma have been treated using a<br />

nonmyeloablative regimen of fludarabine/cyclophosphamide or fludarabine,<br />

cytarabine, cisplatin. 61<br />

All patients had failed to respond or recurred after primary<br />

chemotherapy. Nine patients had CLL in relapse after a prior fludarabine response<br />

<strong>and</strong> six patients had lymphoma. All patients had active disease at the time of<br />

transplant, three had a performance status of 3 (according to Southwest Oncology<br />

Group [SWOG] criteria), two had elevated liver function tests, <strong>and</strong> all had received<br />

extensive prior therapy. The chemotherapy is known to be nonmyeloablative, <strong>and</strong><br />

mixed chimerism was anticipated. Eleven of the 15 patients had evidence of<br />

engraftment as documented by acquisition of donor type restriction fragment<br />

length polymorphisms. The percentage of donor cells in the <strong>marrow</strong> ranged<br />

between 50 <strong>and</strong> 100% at 1 month posttransplant. One had 75% donor cells in his<br />

<strong>marrow</strong> at 6 weeks posttransplant, <strong>and</strong> converted to 100% donor cells following a<br />

donor lymphocyte infusion. Hematopoietic recovery was prompt <strong>and</strong>, with the<br />

exception of a patient with hepatitis C, no patient had a nonhematologic toxicity of<br />

greater than grade 2. The patients failing to engraft recovered endogenous<br />

hematopoiesis promptly <strong>and</strong> had no serious adverse effects. Increasing the intensity<br />

of the immunosuppression may increase the rate of engraftment. The minimal<br />

toxicity <strong>and</strong> mild cytopenias indicate the potential feasibility of administering this<br />

procedure on an outpatient basis. All 11 patients with engraftment have responded,

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