Cord blood transplants supported by co-infusion of mobilized hematopoietic stem cells from a third-party donor

This open label clinical study provides updated evaluation of the strategy of single unit cord blood transplants (CBTs) with co-infusion of third-party donor (TPD) mobilized hematopoietic stem cells (MHSC). Fifty-five adults with high-risk hematological malignancies, median age 34 years (16-60 years) and weight 70 kg (43-95 kg), received CBTs (median 2.39 x 10(7) total nucleated cell (TNC) per kg and 0.11 x 10(6) CD34+ per kg) and TPD-MHSC (median 2.4 x 106 CD34+ per kg and 3.2 x 10(3) CD3+ per kg). Median time to ANC and to CB-ANC >0.5 x 10(9)/1 as well as to full CB-chimerism was 10, 21 and 44 days, with maximum cumulative incidences (MCI) of 0.96, 0.95 and 0.91. Median time to unsupported platelets >20 x 10(9)/1 was 32 days (MCI 0.78). MCI for grades I-IV and III-IV acute GVHD (aGVHD) were 0.62 and 0.11; 12 of 41 patients (29%) who are at risk developed chronic GVHD, becoming severely extensive in three patients. Relapses occurred in seven patients (MCI = 0.17). The main causes of morbi-mortality were post-engraftment infections. CMV reactivations were the most frequent, their incidence declining after the fourth month. Five-year overall survival and disease-free survival (Kaplan-Meier) were 56% and 47% (63% and 54% for patients <= 40 years). In conclusion, CBT with single units of relatively low cell content and 0-3 HLA mismatches is feasible as a first choice option for adult patients who lack a readily available adequate adult donor.