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Journal of Hematology - Supplements - Haematologica

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14<br />

fact the common feature <strong>of</strong> these protocols is<br />

that intensive short-term immunosuppression is<br />

performed in order to induce host tolerance<br />

against donor cells which in turn enable a potent<br />

GVL effect by large numbers <strong>of</strong> donor-derived<br />

immunocompetent T-cells. GVL is then enhanced<br />

by subsequent DLI, if needed.<br />

Here below we report the conditioning regimens<br />

adopted by most Institutions.<br />

Condition regimens<br />

Hadassah University Hospital (Jerusalem). The basic<br />

protocol is fludarabine (30 mg/m 2 /d for 6 consecutive<br />

days), oral busulfan 4 mg/kg/d for 2<br />

consecutive days and anti-T-lymphocyte globulin<br />

ATG (5-10 mg/kg/d Fresenius for 4 consecutive<br />

days). This schedule has been subsequently modified<br />

in selected patients with genetic disease or<br />

aplastic anemia in that busulfan was substituted<br />

by cyclophosphamide, or low dose TBI in single<br />

dose (200 cGy).<br />

MD Anderson (Houston). Fludarabine 30 mg/<br />

m 2 /d and Ara-C 2 g/m 2 /d for 4 days, idarubicin<br />

12 mg/m 2 /d for 3 days. Patients previously<br />

exposed to fludarabine received Ara-C 1 g/m 2 /d<br />

and 2-CDA at a dose <strong>of</strong> 12 mg/m 2 /d for 5 days.<br />

Fred Hutchinson (Seattle). Low-dose TBI (200<br />

cGy) in a single dose.<br />

Ospedale San Martino (Genoa). Thiothepa 10<br />

mg/kg 1 dose, then cyclophosphamide 50<br />

mg/kg/d for 2 days.<br />

Another approach based on autografting followed<br />

by non-myeloablative allograft was proposed<br />

in alternative to this protocol. In this case<br />

conditioning includes fludarabine 30 mg/kg/d<br />

and cyclophosphamide 300 mg/m 2 /d for 3 days.<br />

San Raffaele Hospital (Milan). Thiothepa 5 to 15<br />

mg/kg according to the age <strong>of</strong> the patient, fludarabine<br />

60 mg/m 2 and cyclophosphamide 60<br />

mg/kg. Infusion <strong>of</strong> engineered lymphocytes<br />

(thymidine kinase gene) in subsequent weeks was<br />

planned.<br />

Harvard Medical School (Boston). Cyclophosphamide<br />

50 mg/kg/d for 4 days and thymic irradiation.<br />

University Hospital Carl Gustav (Dresden). Busulfan<br />

3.3 mg/kg/d i.v. or 4 mg/kg/d p.o. for 2 days<br />

and fludarabine 30 mg/m 2 /d for 5 days.<br />

In order to infuse a higher number <strong>of</strong> CD34 +<br />

cells and T-lymphocytes, peripheral blood stem<br />

cells were used in most cases. In some cases bone<br />

harvest and in a few patients cord blood were<br />

used as the stem cell source. GVHD prophylaxis<br />

consisted <strong>of</strong> cyclosporinA (CSA), CSA and a<br />

short course <strong>of</strong> methotrexate (MTX), CSA and<br />

methylprednisolone, CSA and m<strong>of</strong>etil mycophenolate<br />

(MMF). CSA administration was planned<br />

for a shorter period <strong>of</strong> time compared to standard<br />

protocols and then modulated according<br />

to GVHD severity.<br />

In most cases the donors were matched siblings,<br />

but cases <strong>of</strong> unrelated donors have been<br />

described. Some cases <strong>of</strong> 1-3 locus mis-matched<br />

transplants are reported.<br />

These heterogeneous conditioning regimens<br />

were employed in different settings <strong>of</strong> patients. In<br />

the first experiences these protocols were suggested<br />

for patients aged more than 50-55 years<br />

and therefore not eligible for conventional transplant,<br />

or for heavily pre-treated younger patients<br />

with reduced performance status or who had<br />

relapsed after a first autologous or allogeneic<br />

transplant. 10,19-20,21,27-29 Conversely the Hadassah<br />

team explored these transplants also in patients<br />

eligible for standard treatment and in non-malignant<br />

diseases. 10,32-34,37,40,41 These wide differences<br />

make the comparison <strong>of</strong> data and results from<br />

various reports difficult; furthermore it must be<br />

remembered that these results emerge from pilot<br />

and ongoing studies with a short follow-up.<br />

Results and Conclusions<br />

Based on cumulative experience reported in the<br />

literature it may be argued that allogeneic nonmyeloablative<br />

regimens are much better tolerated<br />

than standard protocols, leading to a similar<br />

or even lower toxicity than conventional<br />

chemotherapy, improving quality <strong>of</strong> life and cost<br />

effectiveness. 25,27,28<br />

Limited non-hematologic and hematologic toxicity<br />

and faster recovery compared to those produced<br />

by standard protocols were observed in<br />

almost all cases. Similarly, transfusional support<br />

and antibiotic administration as well as time<br />

spent in hospital were reduced in the majority <strong>of</strong><br />

recipients <strong>of</strong> non-myeloablative regimens compared<br />

to in recipients <strong>of</strong> standard transplants.<br />

Engraftment and stable full or mixed chimerism<br />

were observed in about 90% <strong>of</strong> patients receiving<br />

either HLA-identical or mis-matched transplants,<br />

but this percentage reached 100% in some studies.<br />

Interestingly it has been well documented that<br />

host-derived cells may slowly disappear leading to<br />

complete chimerism development. This confirms<br />

that once a state <strong>of</strong> tolerance is achieved, donor<br />

cells engraftment is progressively able to replace<br />

normal and malignant cells through a non-clinical<br />

GVH reaction. Lasting mixed chimerism was<br />

observed also in haplo-identical settings. 10,12,13,27,28<br />

Concerning the control <strong>of</strong> underlying disease,<br />

results should be carefully reviewed in consideration<br />

<strong>of</strong> the advanced stage <strong>of</strong> disease in most<br />

patients, the heterogeneity <strong>of</strong> the cases and the<br />

relatively short follow-up. Preliminary results<br />

confirm that non-ablative regimens may control<br />

the neoplastic disease also in advanced stage,<br />

but, albeit encouraging results, recurrence <strong>of</strong> disease<br />

remains the most important cause <strong>of</strong> trans-<br />

haematologica vol. 85(supplement to n. 11):November 2000

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