Comparison of Haploidentical T-Replete HSCT Followed with Post-Transplant
High Dose Cyclophosphamide (PT-HDCy) with Matched Related (MRD) or Unrelated (UD) HSCT in Patients in or after the 6TH Decade

The identification of a donor has always limited the extent of allo HSCT. Recently it has been shown that a haploidentical donor could be a valid option to perform allo HSCT given adapted immunosuppression is used. Notably the use of PT-HDCy, after T-replete HSCT following reduced intensity (RIC) or non-myeloablative (NMAC) conditioning, has been associated with promising results. However little data exist concerning elderly population when this population is characterized by a lack of HLA matched sibling and a higher incidence of severe GVHD and non-relapse mortality.

Using this strategy we transplanted 31 patients over the age of 55 years between 2010 and 2014 and compare their outcome with patients of the same age transplanted in the same period from a MRD or UD.

70% of the patients in haplo group were prepared with Flu-TBI 2gy (NMAC) (30% received Fludarabine-Busilvex based regimen without ATG) while all patients in other groups received the same RIC (Fludarabine (150 mg/m2) –Busilvex (2 days) –rabbit ATG (2 days)). Patients in haplo group received post graft Immunosuppression with PT-HDCy (50 mg/kg on D 3 and 4) followed with CSA and MMF while patients in other groups received either CSA starting on D1. 


Patients in the haplo group have a trend presenting higher comorbidities and more severe diseases (Table). A single graft failure related to donor anti-HLA antibodies were noted in haplo group. Median time to 0.5 x10⁹ ANC and 20x10⁹ platelets were respectively 21 (14-32) and 28 (14-52) days after haplo HSCT. Haplo and MRD HSCT patients presented with a similar NRM lower than UD patients while Haplo patients present a relapse rate intermediate between MRD and UD (table). Overall outcome after haplo do not differ from MRD transplant.  There is a trend for better PFS after Haplo HSCT as compared with UD transplant (62% vs.41%; P=0,14) (Figure 1). Progression-free and severe cGVHD-free survival was significantly better after haplo HSCT (62% vs. 35%; p=0.03) (Figure 2)


We conclude that T-replete Haplo HSCT after RIC and followed by PT-HDCy is associated with promising results notably as compared with UD HSCT. The low rate of severe aGVHD and cGVHD are likely to conduct to lower complications and better quality of life. The reduction of donor search duration and the absence of graft acquisition fees represent potential additional benefits. In this perspective, the place of Haplo HSCT in older patients should now be prospectively addressed.