Transplantation characteristics and comparison of patients in the three age groups:
We analyzed data from 2645 patients aged from 0 to 40 years old, who received a first allogeneic HSCT between January 2005 and December 2017 from 43 SFGM-TC centers. The patient’s characteristics are presented in Table 1.
Table 1
Patient and transplantation characteristics
N = 2645
|
Group 1
(0–14 y)
N = 564 (%)
|
Group 2
(15–25 y)
N = 647 (%)
|
Group 3
(26–40 y)
N = 1434 (%)
|
P
|
Patients characteristics
|
|
|
|
|
Male
|
315 (56.0%)
|
346 (53.5%)
|
716 (50.0%)
|
0.0431
|
Female
|
249 (44.0%)
|
301 (46.5%)
|
717 (50.0%)
|
|
Median (min-max) age at AML diagnosis (years)
|
6.7(0.0-14.89)
|
20.0(0.6–25.6)
|
33.8(13.6–40.0)
|
< 0.0001
|
Median (min-max) age at transplantation (years)
|
7.6(0.3–15)
|
20.9(15.0-25.9)
|
34.6(26.0–40.0)
|
< 0.0001
|
Cytogenetics (n = 1972)
|
|
|
|
< 0.0001
|
Low risk
|
76 (19.0%)
|
99 (20.5%)
|
234 (21.5%)
|
|
Intermediate risk 1
|
45 (11.0%)
|
100 (20.5%)
|
283 (26.0%)
|
|
Intermediate risk 2
|
99 (24.5%)
|
124 (25.5%)
|
243 (22.5%)
|
|
High risk
|
183 (45.5%)
|
163 (33.5%)
|
323 (30.0%)
|
|
Extra-medullary involvement at diagnosis
|
288 (51.0%)
|
224 (35.0%)
|
463 (32.0%)
|
< 0.0001
|
Status at transplantation
|
|
|
|
< 0.0001
|
CR1
|
327 (60.0%)
|
396 (63.0%)
|
899 (64.5%)
|
|
≥CR2
|
170 (31.0%)
|
141 (22.5%)
|
259 (18.5%)
|
|
Refractory
|
49 (9.0%)
|
91 (14.5%)
|
237 (17.0%)
|
|
Type of donor (% among groups)
|
|
|
|
< 0.0001
|
MRD/Syngeneic
|
198 (35.2%)
|
233 (36.0%)
|
555 (38.8%)
|
|
MUD
|
198 (35.2%)
|
224 (34.6%)
|
540 (37.7%)
|
|
MMUD
|
149 (26.5%)
|
149 (23.0%)
|
250 (17.5%)
|
|
Haploidentical
|
18 (3.2%)
|
41 (6.3%)
|
86 (6.0%)
|
|
Donor age (median, min-max)
|
21.96
(0.07–57.94)
|
27.18
(0.08–64.16)
|
34.57
(1.54–72.96)
|
< 0.0001
|
Source of stem cells
|
|
|
|
< 0.0001
|
Bone marrow
|
356(63.2%)
|
260(40.2%)
|
404(28.2%)
|
|
Peripheral Blood Stem Cell
|
55(9.8%)
|
297(45.9%)
|
894(62.3%)
|
|
Cord blood
|
152(27%)
|
90(13.9%)
|
136(9.5%)
|
|
Conditioning regimen
|
|
|
|
< 0.0001
|
MAC
|
522(95.3%)
|
490(79%)
|
1063(76.1%)
|
|
RIC
|
20(3.6%)
|
76(12.3%)
|
197(14.1%)
|
|
Sequential
|
6(1.1%)
|
54(8.7%)
|
137(9.8%)
|
|
TBI based (≥ 8Grays)
|
42(7.5%)
|
166(25.7%)
|
367(25.6%)
|
< 0.0001
|
Description of MAC conditioning regimen
|
|
|
|
< 0.0001
|
BuCy
|
403(73.0%)
|
221(34.4%)
|
428(30.1%)
|
|
FB4
|
34(6.1%)
|
93(14.5%)
|
262(18.3%)
|
|
TBI-Cy
|
27(4.9%)
|
133(20.7%)
|
309(21.7%)
|
|
Other
|
88(16.0%)
|
195(30.4%)
|
424(29.9%)
|
|
GvHD prophylaxis
|
|
|
|
< 0.0001
|
CSA-MTX
|
167(31.6%)
|
305(51.0%)
|
729(54.5%)
|
|
CSA-MMF
|
72(13.6%)
|
176(29.4%)
|
406(30.4%)
|
|
CSA alone
|
290(54.8%)
|
117(19.6%)
|
202(15.1%)
|
|
ATG in vivo T depletion
|
237(42.0%)
|
277(42.8%)
|
702(49.0%)
|
0.0036
|
Post-Transplant High-dose Cyclophosphamide (PTCy)
|
15(2.6%)
|
40(6.2%)
|
87(6.1%)
|
0.0056
|
Use of PT-Cy in Haploidentical HSCT
|
9(50%)
|
30(73.2%)
|
54(62.8%)
|
0.2137
|
Donor lymphocyte infusions
|
34(6.0%)
|
61(9.4%)
|
180(12.6%)
|
< 0.0001
|
Indication of DLI
Preemptive
|
12(35.3%)
|
20(32.8%)
|
59(32.8%)
|
0.37
|
After relapse
|
21(61.8%)
|
31(50.8%)
|
102(56.7%)
|
|
ATG: Anti-thymoglobulin; BuCY: busulfan 12.8 to 19.2mg/kg and cyclophosphamide 120 or 200 mg/kg; CR: Complete remission; CSA: ciclosporine A; FB4: fludarabine 120 to 160 mg/m2 and busulfan 12.8 to 19.2mg/kg ; GvHD: Graft-versus-host Disease; Haploidentical-HSCT: Haploidentical hematopoietic stem cell transplantation; MAC: Myeloablative Conditioning; MMF: mycophenolate mofetil; MMUD: Mismatched Unrelated Donor (HLA < 10/10); MRD: Matched Related Donor; MTX: methotrexate; MUD: Matched Unrelated Donor (HLA 10/10); RIC: Reduced-Intensity Regimen; TBI: Total Body Irradiation. |
The median follow-up of the study was 2.4 years (min-max 1 day − 14.7 years), from the time of transplant to death or latest news date. Among alive patients, the median follow-up of the study was 4.37 years (min-max 0.18–14.73 years). Three age groups were assessed: 564 children aged from 0 to 14 years, 647 Adolescents and Young Adults (AYAs) aged from 15 to 25 years, and 1434 adult patients aged from 26 to 40 years.
The cytogenetics risk, the extramedullary involvement at diagnosis and the disease status at transplant were different in the 3 groups (p < 0.0001 for all analyses). The conditioning regimen was mainly myeloablative in the 3 groups (79% in AYAs, 76.1% in adults and 95.3% in children), but AYAs and adults received more often RIC regimen than the children (12.3 and 14.1% versus 3.6%). The use of TBI equal and over 8 Grays was different according to the age groups (p < 0.0001), AYAs and adults received more TBI (25.7 and 25.6% respectively) than the children (7.5%). The use of Anti-Thymoglobulin (ATG) was different in the 3 groups (p = 0.0036): it was slightly less often used in AYAs and children compared to the adults (42.8% and 42% versus 49% respectively). Post-Transplant High Dose Cyclophosphamide (PT-Cy) was used in a minority of cases, 2.6% in children, 6.2% in AYAs and 6.1% in adults (p = 0.0056 as intergroup comparison). PT-Cy was not only dedicated to haploidentical transplantations: 63.6% patients that received PT-Cy, underwent a haploidentical transplant and 62.7% haploidentical transplant were followed by PT-Cy. We observed some significant differences in stem cell source between the 3 groups (p < 0.0001). Bone marrow (BM) was the main source in children (63.2%, followed by cord blood in 27%, and peripheral blood stem cells (PBSC) in only 9.8%), PBSC were the major source of HSCT in adults (62.3%, followed by bone marrow in 28.2%) while AYAs received bone marrow in 40.2%, PBSC in 45.9% and cord blood in 13.9%. The donor’s age was also different in the 3 age groups (p < 0.0001).
Engraftment and Graft- versus -Host Disease (GVHD):
The neutrophils recovery time up to 0.5 G/L differed between the 3 age groups (p < 0.0001) with a median (min-max) value of 20 days (4–61) in children, 19 days (1–66) in AYAs, and 18 days (1-108) in adults. The platelets recovery time up to 20 G/L also differed in the 3 age groups (p < 0.0001) with a median (min-max) value of 21 days (3-181) in children, 18 days (1-124) in AYAs and 16 days (1-152) in adults (Table 2).
Table 2
Patient outcomes according to age group
|
Group 1 (0–14 y) n = 564
|
Group 2 (15–25 y)n = 647
|
Group 3 (26–40 y) n = 1434
|
P
|
Median (min-max) follow-up among alive patients in years
|
4.30
(0.21–14.60)
|
4.49
(0.18–14.73)
|
4.37
(0.25–14.24)
|
0.7381
|
Engraftment
|
|
|
|
|
Median (min-max) duration of PNN > 0.5G/L (days)
|
20 (4–61)
|
19 (1–66)
|
18 (1-108)
|
< 0.0001
|
Median (min-max) duration of Platelets > 20G/L (days)
|
21 (3-181)
|
18 (1-124)
|
16 (1-152)
|
< 0.0001
|
Probability at 2y (%)
|
|
|
|
|
OS [95% CI]
|
71.4 [67.4–75.0]
|
61.1 [57.1–64.8]
|
62.9 [60.3–65.4]
|
0.0009
|
EFS [95% CI]
|
61.5 [57.2–65.5]
|
53.7 [49.7–57.6]
|
55.8 [53.1–58.4]
|
0.0186
|
GRFS [95% CI]
|
47.0 [42.7–51.1]
|
40.1 [36.2–44.0]
|
40.9 [38.3–43.5]
|
0.1107
|
Cumulative incidence (%)
|
|
|
|
|
Grade I-IV acute GvHD at 3m [95% CI]
|
55.7 [51.3–59.8]
|
49.3 [45.2–53.2]
|
50.4 [47.7–53.0]
|
0.0534
|
Grade II-IV acute GvHD at 3m [95% CI]
|
37.8 [33.6–42.0]
|
34.6 [30.8–38.4]
|
33.8 [31.3–36.3]
|
0.1940
|
Grade III-IV acute GvHD at 3m [95% CI]
|
13.8 [11.0–17.0]
|
13.1 [10.6–16.0]
|
12.2 [10.6–14.1]
|
0.6097
|
Chronic GvHD at 2y [95% CI]
|
17.5 [14.4–20.8]
|
31.4 [18.4–27.8]
|
36.4 [33.9–38.9]
|
< 0.0001
|
Extensive chronic GvHD at 2y [95% CI]
|
7.1 [5.2–9.3]
|
12.5 [10.0-15.2]
|
15.4 [13.6–17.4]
|
< 0.0001
|
Relapse at 2y [95% CI]
|
30.8 [27.0-34.7]
|
35.2 [31.5–38.9]
|
29.4 [27.0-31.8]
|
0.0254
|
NRM at 2y [95% CI]
|
7.0 [5.1–9.4]
|
10.6 [8.3–13.2]
|
14.2 [12.4–16.1]
|
< 0.0001
|
OS : Overall Survival ; EFS : Event Free Survival ; GvHD : Graft Versus Host Disease ; NRM : Non Relapse Mortality ; GRFS: Graft versus Host Disease and Relapse Free Survival |
The grade I to IV acute GVHD cumulative incidence (CI) at 3 months was estimated to 55.7% for children, 49.3% for AYAs and 50.4% for adults, the difference in the 3 age groups was close to being significant (p = 0.0534) (Table 2). Moreover, considering chronic GVHD, the CI at 2 years of follow-up showed a significant statistical difference in the 3 age groups (p < 0.0001), AYAs and adults experiencing more chronic GVHD (31.4% and 36.4%, respectively) in comparison to the children (CI 17.5%) (Table 2, Fig. 1a and 1b).
The independent risk factors associated with grade II to IV acute GVHD were: the HLA matching (higher risk for mismatched unrelated donors followed by matched unrelated donors and haploidentical donors compared to the sibling donors), active disease at transplant time and the use of TBI ≥ 8 Grays. The protective factors were: the use of cord blood and PBSC, compared to the bone marrow, the use of ATG, the use of Post-Transplant High-Dose Cyclophosphamide (PT-Cy) and methotrexate in addition to cyclosporine in GVHD prophylaxis (Table 3).
Table 3
Multivariable analyses of risk factors for acute and extensive chronic GVHD occurrence
|
aGvHD II-IV
|
aGvHD III-IV
|
|
Extensive cGvHD
|
|
Variable
|
HR [95%IC]
|
p HR [95%IC]
|
p
|
HR [95%IC]
|
P
|
Group of age
0–14 y
15–24 y
25-40y
|
ns
|
|
ns
|
|
1
1.66[1.05–2.61]
1.92[1.24–2.97]
|
0.0131
|
CMV Matching (D/R)
-/-
+/-
-/+
+/+
|
ns
|
|
1
0.77 [0.47–1.26]
1.48 [1.03–2.12]
1.51 [1.07–2.15]
|
0.0078
|
ns
|
|
Disease status at transplantation
CR 1
CR 2
CR 3
Active disease
|
1
0.79 [0.63–0.99]
0.51 [0.12–2.06]
1.59 [1.26-2.00]
|
< 0.0001
|
1
0.61[0.41–0.91]
0.66[0.09–4.75]
1.91[1.35–2.70]
|
< 0.0001
|
ns
|
|
HLA matching
Matched sibling donor
Haploidentical donor
Matched unrelated donor
Mismatched unrelated donor
|
1
1.48 [0.89–2.44]
2.10 [1.69–2.61]
2.59 [1.96–3.41]
|
< 0.0001
|
1
1.43[0.75–2.71]
2.38[1.65–3.42]
2.70[1.80–4.05]
|
< 0.0001
|
ns
|
|
Donor age
|
ns
|
|
ns
|
|
1.01 [1.00-1.03]
|
0.0415
|
Source of stem cells
Bone marrow
PBSC
Cord blood
|
1
0.88 [0.72–1.06]
0.41 [0.29–0.58]
|
< 0.0001
|
ns
|
|
1
1.43[1.09–1.87]
|
0.0085
|
Myeloablative TBI (≥ 8 Grays)
No
Yes
|
1
1.36 [1.11–1.67]
|
0.0023
|
ns
|
|
ns
|
|
GvHD prophylaxis
CsA - alone
CsA - MTX
CsA - MMF
|
1
0.70 [0.56–0.89]
1.02 [0.79–1.30]
|
0.0017
|
ns
|
|
ns
|
|
ATG
No
Yes
|
1
0.34 [0.24–0.47]
|
< 0.0001
|
1
0.47[0.35–0.63]
|
< 0.0001
|
1
0.55[0.42–0.71]
|
< 0.0001
|
HD cyclophosphamide post HSCT
No
Yes
|
1
0.60 [0.37–0.97]
|
0.0370
|
ns
|
|
1
0.31 [0.13–0.71]
|
0.0051
|
ATG: antithymoglobulin; BM: bone marrow; CR: complete remission; GvHD: graft-versus-host disease; CsA: ciclosporine A; MTX: methotrexate; MMF: mycophenolate mofetil; PBSC: peripheral blood stem cells; TBI: total body irradiation. |
ns: variables not retained in the final model due to non-significance |
Furthermore, independent risk factors associated with severe (grade III to IV) acute GVHD were: active disease at transplant time, HLA matching (higher risk in case of mismatched unrelated donors followed by matched unrelated donors and haploidentical donors compared to the sibling donors), and recipient CMV seropositivity. The use of ATG decreased the risk of severe acute GVHD (Table 3).
An independent risk factor of chronic GVHD was identified: the age group, adults being at highest risk, and then AYAs, compared to the children. The use of PT-Cy decreased the risk of chronic GVHD. As far as extensive chronic GVHD is concerned, the graft source (PBSC compared to bone marrow) and the increasing of donor’s age were also an independent risk factor in addition to the age group (adults and AYAs, compared to the children). While the use of ATG or PT-Cy was an independent protective factor in extensive chronic GVHD (Table 3).
Relapse:
With a median follow-up of 2.4 years (min-max: 1 day-14.7 years), AML relapse occurred after HSCT in 193 children (35.2%), 247 AYAs (39.1%) and 474 adults (34.5%). Median (min-max) delay from HSCT to relapse was 165.5 (1-4377) days in children, 151 days (7-2457) in AYAs and 182 days (1-4305) in adults.
The CI of relapse at 2 years differed in the 3 age groups (30.8% in children, 35.2% in AYAs and 29.4% in adults - p = 0.0254) (Table 2, Fig. 2c).
The independent risk factors for relapse were: high cytogenetics risk, followed by intermediate risk 2 and 1 (compared to low cytogenetics risk), longer delay between diagnosis and HSCT, reduced-intensity conditioning regimens (compared to myeloablative conditioning regimens), active disease at transplant time, followed by third and second complete remission before HSCT (compared to the patients in first CR) (Table 4).
Table 4
Multivariable analyses of risk factors of death (OS model), relapse, non-relapse mortality (NRM) and GRFS
|
OS*
|
Relapse
|
|
NRM*
|
|
GRFS*
|
|
Variable
|
HR [95%IC]
|
p HR [95%IC]
|
p
|
HR [95%IC]
|
p
|
HR [95%IC]
|
p
|
Group of age
0–14 y
15–24 y
25-40y
|
NS
|
|
NS
|
|
1
1.32[0.70–2.46]
1.88[1.07–3.30]
|
0.0343
|
NS
|
|
Sex Matching (D/R)
M-M
F-M
M-F
F-F
|
NS
|
|
NS
|
|
NS
|
|
1
1.07[0.88–1.30]
0.92[0.76–1.10]
1.22[1.01–1.49]
|
0.0377
|
CMV Matching (D/R)
-/-
+/-
-/+
+/+
|
NS
|
|
NS
|
|
NS
|
|
1
0.84[0.67–1.06]
1.16[0.96–1.41]
1.18[0.99–1.40]
|
0.0130
|
Cytogenetics
Low risk
intermediate 1
Intermediate 2
high risk
|
1
1.73[1.29–2.32]
1.50[1.13–2.01]
2.22[1.70–2.89]
|
< 0.0001
|
1
1.46[1.10–1.93]
1.58[1.21–2.06]
1.87[1.45–2.41]
|
< 0.0001
|
1
1.65[1.00-2.72]
1.05[0.61–1.79]
1.69[1.05–2.72]
|
0.0394
|
1
1.29[1.02–1.63]
1.15[0.91–1.45]
1.37[1.11–1.70]
|
0.0184
|
Delay between AML diagnosis and HSCT (days)
|
NS
|
|
1 [0.99-1.00]
|
0.0192
|
NS
|
|
NS
|
|
Disease status at transplantation
CR 1
CR 2
CR3
Active Disease
|
1
1.40[1.10–1.78]
2.26[1.02–4.98]
3.07[2.44–3.85]
|
< 0.0001
|
1
1.44 [1.10–1.88]
1.57 [0.62–3.99]
2.76 [2.08–3.67]
|
< 0.0001
|
1
1.45[0.95–2.22]
3.54[1.25–9.95]
2.27[1.47–3.49]
|
0.0004
|
1
1.11[0.89–1.38]
2.36[1.16–4.76]
3.04[2.45–3.78]
|
< 0.0001
|
HLA matching
Matched sibling donor
Haploidentical
Matched unrelated donor
Mismatched unrelated donor
|
NS
|
|
NS
|
|
1
2.55[1.50–4.30]
1.55[1.06–2.27]
1.45[0.87–2.43]
|
0.0083
|
1
1.41[1.05–1.89]
1.46[1.18–1.81]
1.73[1.29–2.34]
|
0.0032
|
Donor age
|
1.01 [1.00-1.02]
|
0.0013
|
NS
|
|
1.03 [1.01–1.04]
|
0.0002
|
1.01[1.00-1.02]
|
0.0049
|
Source of stem cells
Bone marrow
PBSC
|
1
1.26 [1.05–1.50]
|
0.0104
|
NS
|
|
NS
|
|
1
1.16[1.01–1.35]
|
0.0465
|
Conditioning regimen
Myeloablative
Reduced-Intensity
Sequential
|
NS
|
|
1
1.37[1.07–1.75]
0.94[0.65–1.37]
|
0.0179
|
NS
|
|
NS
|
|
Myeloablative TBI (≥ 8 Grays)
No
Yes
|
1
1.33 [1.09–1.61]
|
0.0036
|
NS
|
|
NS
|
|
NS
|
|
ATG: antithymoglobulin; BM: bone marrow; CR: complete remission; GVHD: graft-versus-host disease; MAC : myeloablative conditioning; methotrexate; PBSC: peripheral blood stem cells; TBI: total body irradiation. |
ns: variables not retained in the final model due to non-significance *Factors are expressed as risk of mortality |
Donor lymphocyte infusions (DLI) were rarely used in this cohort, either in prophylaxis or as curative treatment. Thirty-four (6%) children, 61 (9.4%) AYAs and 180 (12.6%) adults received at least one DLI.
Non-relapse mortality:
The non-relapse mortality CI at 2 years was 7.0 % in children, 10.6% in AYAs and 14.2% in adults (p < 0.0001, Table 2, Fig. 2d) and the median (min-max) delay from HSCT to NRM was 0.34 (0.06–6.54) years, 0.33 (0.01–8.20) years and 0.45 (0-13.49) years, respectively.
The independent risk factors for NRM were: the age group (adults followed by AYAs had a higher risk of NRM, compared to the children), the cytogenetics risk (high risk followed by intermediate risk 1and 2, compared to low risk), the disease status at transplant (third CR followed by active disease and second CR, compared to first CR), the HLA mismatch (haploidentical donors followed by mismatched unrelated donors and then matched unrelated donors, compared to the identical sibling donors) and the increasing of donor’s age (Table 4).
The causes of death (other than relapse) are described in supplementary Table 1. Children mostly died of infections (n = 21, 10.7%), GVHD (n = 20, 10.2%) and pulmonary toxicity (n = 9, 4.6 %). Adolescents and young adults like adults mostly died of infections (n = 53, 18.3% and n = 142, 21.9%; respectively), GVHD (n = 40, 13.8% and n = 125, 19.3%) and sinusoidal obstruction syndrome (n = 14, 4.8% and n = 21, 3.2%).
OS and EFS:
In this cohort, 1513 patients were alive (57.2%) after a median follow-up of 4.37 years, 368 children (65.2%), 358 AYAs (55.3%) and 787 adults (54.9%). The OS was significantly different between the 3 groups (p = 0.0003, Fig. 2a). At 2 years, the probability of OS was 71.4% in children, 61.1% in AYAs and 62.9% in adults (p = 0.0009 as intergroup difference, Table 2). In the subgroup of patients who did not relapse (n = 1641 patients), the probability of 2 year-OS also differed in the 3 age groups (p < 0.0001) with 89.2% in children, 82.5% in AYAs and 78.2% in adults.
The independent risk factors for death were: high cytogenetics risk, followed by intermediate risk 1 and 2 (compared to low risk), the use of TBI ≥ 8 Grays, active disease at transplant time followed by the patients in 3rd CR and 2nd CR (compared to the patients in 1st CR), the use of PBSC (compared to bone marrow), and the increase of donor’s age (Table 4).
The EFS was also different in the 3 age groups (p = 0.013, Fig. 2b) at 2 years with a rate of 61.5% in children, 53.7% in AYAs and 55.8% in adults, p = 0.0186 (Table 2).
The independent risk factors for death or relapse were: high cytogenetics risk followed by intermediate risk 1 and 2, TBI ≥ 8 Grays in the conditioning regimen, active disease at transplant time followed by 3rd CR and 2nd CR, and the increasing of donor’s age.
GRFS (Figure 1c):
The GRFS, who was defined as survival without neither grade III-IV acute GVHD nor extensive chronic GVHD or relapse, was not significantly different in the 3 age groups (p = 0.0997, Fig. 1c). The probability of GRFS at 2 years was 47% in children, 40.1% in AYAs and 40.9% in adults, p = 0.1107 (Table 2).
The independent protective factors for survival without neither disease nor GVHD were: CMV seronegative recipient (in particular the combination of positive donor and negative recipient), AML with low cytogenetics risk, male donor, transplant in 1st CR, bone marrow (compared to PBSC), younger and matched sibling donor (Table 4).
Additional analysis:
In order to describe more precisely the impact of the conditioning regimen and the stem cell source on OS, NRM and chronic GvHD for AYAs, we compared in a subgroup study the AYAs who received a chemotherapy-based MAC regimen and bone marrow as stem cell source i.e. 171 patients (6.5%), other AYAs i.e. 449 patients (17.2%) and the children i.e. 564 patients (21.5%) (Fig. 3). We found a better survival for AYAs who received a chemotherapy-based regimen and bone marrow (p < 0.0001) (Fig. 3a), and the NRM was lower for this subgroup of patients (p = 0.0153) (Fig. 3b). However, the incidence of chronic GvHD was still lower for children (p < 0.0001) (Fig. 3c). Moreover, the OS was the same for children and AYAs who received bone marrow, compared to AYAs who received other stem cells sources (Fig. 3d).