3). Fifteen patients had improvement in, or correction of, their underlying PIDD. Although these results are preliminary, our early experience suggests that outcomes can be improved in high-risk patients with PIDD by using a modified nonmyeloablative conditioning regimen and by selecting marrow as the source of hematopoietic cells. We observed stable donor engraftment in most cases, an acceptable TRM, a low incidence of chronic GVHD, and correction of underlying disease processes. Many patients

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... lack an HLA-matched donor. We evaluated whether the use of a fixed dose of CD3 1 cells with megadoses of CD34 1 cells from Haplocompatible related donors (HRDs) would be associated with good outcomes in children. From 2002 to 2010, we performed a prospective Phase II trial utilizing the CliniMACs (Miltenyi Biotec, Bisley, UK) system to perform CD34 1 cell selection of PBSC from HRDs in 21 pediatric patients (median age 6.4 yrs, range 1.4-20.5 yrs). 15 patients had a hematologic malignancy (AML/MDS, n 5 9; ALL, n 5 4; CML, n 5 1; JMML, n 1), 6 patients had a non-malignant condition (Bone Marrow Failure, n 5 3; HLH, n 3). Conditioning was TBI 1200 cGy (200 cGy bid on Days -9 to -7), Thiotepa (5 mg/kg/dose bid on Day -6), Fludarabine (40 mg/m 2 /dose on Days -6 to -2), and Thymoglobulin (0.5 mg/kg on Day -5, 1 mg/kg on Days -4 to -2). Patients received a median of 20 Â 10 6 /kg (range: 11-33 Â 10 6 /kg) CD34 1 cells with 3 Â 10 4 /kg CD3 1 cells/kg. Events were: graft failure, relapse, and TRM. Statistics were performed using SPSS 16.0. EFS was estimated using the Kaplan-Meier method. Engraftment occurred in all but 2 patients (90%; 95% CI, 70-99%), both with AML/MDS. Relapse occurred in 3 of 15 patients (20%; 95% CI, 6-46%) at a median of 3.7 months (range: 1.3-12.4 months) post-HCT. All 5 patients eventually expired, despite 2 nd HRD HCT for 4 patients. One or more planned DLI (3 Â 10 4 CD3 1 cells/kg) were administered to 11 patients to enhance immunologic recovery. Grade I-II aGVHD was seen in 9 of 19 evaluable patients (47%; 95% CI, 27-68%). There was no Grade III-IV aGVHD. cGVHD was seen in 6 of 17 evaluable patients (35%; 95% CI, 17-59%). Infections (Sepsis & Mucor) resulted in the death of 2 patients (10%; 95% CI, 1-30%) at 11 & 22 months post-HCT; both were being treated for cGVHD. For all patients, the est. 2-year EFS was 61% (95% CI, 49-73%). Patients with non-malignant diseases had an est. 2-year EFS of 100% (95% CI, 56-100%). Patients with malignancy in remission (n 9) had an est. 2-year EFS of 64% (95% CI, 47-80%), while those not in remission (n 6) had an est. 2-year EFS of only 22% (95% CI, 3-41%). Median follow-up of survivors was 34 months (range: 3-103 months). Megadose CD34 1 cells with a fixed CD3 1 cell dose from HRDs resulted in outcomes similar to those seen with other alternativedonor stem cell sources. For pediatric patients with non-malignant diseases or those transplanted in remission, outcomes were excellent.